UTRECHT MICROPALEONTOLOGICAL BUllETINS

Transcription

1 UTRECHT MICROPALEONTOLOGICAL BUllETINS CALCAR EOUS NAN NOPLAN KTON B IOSTRA T1G RAPHY OF MIDDLE AND UPPER CRETACEOUS DEPOSITS IN TUNISIA, SOUTHERN SPAIN AND FRANCE 16

2 Editor C. W. Drooger Department of Stratigraphy and Paleontology State University of Utrecht Oude Gracht 320, Utrecht, Netherlands Bull. 1. T. FREUDENTHAL - Stratigraphy of Neogene deposits in the Khania Province, Crete, with special reference to foraminifera of the family Plan orbulinidae and the genus Heterostegina. 208 p., 15 pl., 33 figs. (1969) f 32,- Bull. 2. J. E. MEULENKAMP - Stratigraphy of Neogene deposits in the Rethymnon Province, Crete, with special reference to the phylogeny of uniserial Uvigerina from the Mediterranean region. 172 p., 6 pi, 53 figs. (1969) f 29,- Bull. 3.J. G. VERDENIUS - Neogene stratigraphy of the Western Guadalquivir basin, S. Spain. 109 p., 9 pl., 12 figs. (1970) f28,- Bull. 4. R. C. TJ ALSMA - Stratigraphy and foraminifera of the Neogene of the Eastern Guadalquivir basin, S. Spain. 161 p., 16 pl., 28 figs. (1971) f 44,- Bull. 5. C. W. DROOGER, P. MARKS, A. PAPP et al. - Smaller radiate Nummulites of northwestern Europe. 137 p., 5 pl., 50 figs. (1971) f 37,- Bull. 6. W. SISSINGH - Late Cenozoic Ostracoda of the South Aegean Island arc. 187 p., 12 pl., 44 figs. (1972) f57,- Bull. 7. author's edition. F. M. GRADSTEIN - Mediterranean Pliocene Globorotalia, a biometrical approach. 128 p., 8 pl., 44 figs. (1974) f39,- Bull. 8. J. A. BROEKMAN - Sedimentation and paleoecology of Pliocene lagoonalshallow marine deposits on the island of Rhodos (Greece). 148 p., 7 pl., 9 figs. (1974) f 47,- Bull. 9. D. S. N. RAJU - Study of Indian Miogypsinidae. 148 p., 8 pl., 39 figs. (1974) f38,- Bull. 10. W. A. VAN WAMEL - Conodont biostratigraphy of the Upper Cambrian and Lower Ordovician of north-western Oland, south-eastern Sweden. 128p., 8pl.,25 figs. (1974) f40,- Bull. 11. W. J. ZACHARIASSE - Planktonic foraminiferal biostratigraphy of the Late Neogene of Crete (Greece). 171 p., 17 pl., 23 figs. (1975) f52,-

3 CALCAREOUS NANNOPLANKTON BIOSTRATIGRAPHY OF MIDDLE AND UPPER CRETACEOUS DEPOSITS IN TUNISIA, SOUTHERN SPAIN AND FRANCE

4 Page Abstract Chapter I. Introduction Purpose of the investigation Previous studies Method of investigation Acknowledgements Chapter II. The sections El Burrueco El Kef Javernant Stratotypes ; Chapter III. Zonation Prediscosphaera columnata Zone Eiffellithus turriseiffeli Zone Lithraphidites acutum Zone Gartnerago obliquum Zone Quadrum gartneri Zone Eiffellithus eximius Zone Marthasterites furcatus Zone Broinsonia lacunosa Zone Micula concava Zone Rucinolithus hayii Zone Zygodiscus spiralis Zone Broinsonia parca Zone Ceratolithoides aculeus Zone Quadrum gothicum Zone Quadrum trifidum Zone Lithraphidites quadratus Zone Micula murus Zone Chapter IV. Correlation with the stratotypes of Middle and Upper Cretaceous stages in Europe Introduction Albian Cenomanian

5 Turonian '.'. Coniacian. Santonian. Campanian. Maastrichtian. Chapter V. Remarks on terminology. Introduction. General. The margin. The central area. Definitions of new terms. Chapter VI. Remarks on evolution. Ceratolithoides. Eiffellithus. Broinsonia. Chapter VII. Taxonomy. References. Index. 22 figures, 12 plates ,

6 The calcareous nannoplankton floras of sections in Tunisia, Southern Spain and France have been investigated leading to a succession of 17 biozones for the Middle and Upper Cretaceous, of which the Rucinolithus hayii Zone for the Middle Santonian is new. In order to correlate the zonation with the chronostratigraphic scale the calcareous nannofossil contents of the stratotypes of the commonly used European Middle and Upper Cretaceous stages have been investigated. The nannofloras of the Cenomanian and Turonian Stages have been published in earlier papers and the stratotype of the Coniacian Stage contains no calcareous nannofossils. From the samples used for the present study the planktonic foraminifera have also been studied to obtain a first order correlation between the zonations based on calcareous nannoplankton and planktonic foraminifera. Evolutionary trends have been recognized and are described in detail in the genera Ceratolithoides, Eiffellithus and Broinsonia. For the description of the calcareous nannofossils the generally accepted terminology is used, completed with some new terms. Remarks have been made on the observed taxa and several new combinations are proposed.

7 Calcareous nannoplankton is a composite group for the skeletal elements of the coccosphaeres of golden brown algae. The size of these elements usually is smaller than about SO p. The group includes nannofossils of uncertain origin with a rather unusual shape, of which a coccosphaere or part of a coccosphaere has so far not been reported. The oldest known elements considered as calcareous nannofossils are reported from Paleozoic deposits (Noel, 1961; Deflandre, 1970; Pirini Radrizzani, 1971; Gartner and Gentile, 1972). As pointed out by Gartner and Gentile (1972), the assignment of these fossils to the calcareous nannofossils is rather doubtful. The stratigraphic record in the Paleozoic seems to be discontinuous and some of these "fossils" may be of inorganic origin. The more continuous record starts in the Lower Jurassic (Prins, 1969; Barnard and Hay, 1974) and extends without interruption to the Recent. The present study deals with the nannoplankton of the Middle Albian-Upper Maastrichtian interval. The purpose of this study was to develop a zonation for the Middle Albian to Upper Maastrichtian based on calcareous nannofossils. A preliminary version of this zonation was published already (Verbeek, 197 6b). For the zonation now proposed, full profit is gained from the criticism received from several colleagues. The calcareous nannofossils of the investigated interval are described in the systematic part of the paper. An attempt has been made to recognize evolutionary trends. Some selected taxa were therefore given special attention. In order to establish a detailed zonation, sections that cover long stratigraphic intervals without notable gaps in the sedimentation were required. The Kef section in Tunisia contains a rather complete sequence from Albian to Maastrichtian of which the Upper Cenomanian to Upper Maastrichtian interval was studied. The section forms the primary control for the proposed zonation. Other sequences which are shorter, but useful for well defined portions of the Middle and Upper Cretaceous are those of El Burrueco (Southern Spain) and J avernant (Paris Basin).

8 Subsequently the scattered stratotypes of the European Middle and Upper Cretaceous stages have been correlated to the proposed zonation, whenever possible. The same sections and samples have been studied for planktonic foraminifera by A. A. H. Wonders (in preparation). This allows a direct comparison between the calcareous nannoplankton zonation and a zonation based on planktonic foraminifera. Results of this comparison are presented as well. Arkhangelsky (1912) published the first paper on systematics of Upper Cretaceous calcareous nannofossils, as a part of his study of the Upper Cretaceous of the USSR. This is the only paper dealing with this subject from the first half of the 20th century. In 1952 Deflandre started a series of papers on Upper Cretaceous calcareous nannofossils. At about the same time Deflandre and Fert (1952, 1954) introduced the use of the electron microscope as a means to obtain more detailed observations. Most of Deflandre's publications that followed described a few species at a time. In 1959 he gave a more extensive review of the Upper Cretaceous calcareous nannofossil taxonomy. Gorka (1957) described the nannoflora of the Maastrichtian of Poland. Her figures are rather schematic, which makes the recognition of her new species somewhat difficult. In 1967 Reinhardt and Gorka revised some of Gorka's species and gave better illustrations. The third author on calcareous nannofossils from Upper Cretaceous sediments between 1950 and 1960 was Vekshina (1959), who worked on the Maastrichtian of Western Siberia. Vekshina used the electron microscope to figure her new species and gave detailed descriptions. After 1960 the number of authors increased. In Austria Stradner started to publish (1961, 1962, 1963). At first his work was only of taxonomic interest, afterwards he also considered biostratigraphy. In the DDR Reinhardt (1964, 1965, 1966a, b, 1967, 1969, 1970a, b, 1971) refined the taxonomy by using the electron microscope and a quartz plate in the light microscope to observe the details of the structure of calcareous nannofossils. In 1964 Bramlette and Martini published their paper on the mass extinction of calcareous nannofossils at the Cretaceous-Tertiary boundary. After 1966 a large number of publications appeared with numerous welldocumented and well-figured species. Papers which contain the most useful information about Middle and Upper Cretaceous calcareous nannoplankton taxonomy are those of Stover (1966, France, Netherlands), Perch-Nielsen

9 (1968, Denmark), Gartner (1968, Texas, Arkansas), Bukry (1969, Texas, Europe), Noel (1969, 1970, Paris Basin), Thierstein (1971, 1973, France, Switzerland, Atlantic Ocean), Manivit (1971, France), Black (1972, 1973, Great Britain). Investigations on Cretaceous calcareous nannofossils from Northern Africa were carried out by Shafik and Stradner (1971) and by Perch-Nielsen (1973), who studied material from Egypt. Sales (1967) published on nannofossils from Western Africa. Sissingh (1977) studied the calcareous nannofossils of the Kef section (Tunisia) for biostratigraphic purposes. The same section is used in this paper. Well-established and generally accepted zonations based on calcareous nannofossils have been composed for the whole interval from Jurassic to Recent. Martini (1971) recognized 46 zones in the Cenozoic. Thierstein (1971, 1973) published nine zones for the Berriasian to Cenomanian. A zonation for the Jurassic was proposed by Barnard and Hay (1974) and contains 22 zones, of which the uppermost one is the same as the lowermost one of Thierstein (1971,1973). The first time calcareous nannofossils were used for biostratigraphical purposes in the Middle and Upper Cretaceous was in 1963, when Stradner recognized five associations for the Albian-Maastrichtian interval. Two of his markers are considered to be useful until today. Cepek and Hay (1969a, b) published a more detailed zonation for the Upper Cretaceous. In the sections they studied from Kansas and Alabama, the interval from Upper Turonian to Lower Campanian is missing (Smith, 1975). This is probably the reason why the middle part of their zonation could not be recognized elsewhere. The zonation of Manivit (1971) made for the Middle and Upper Cretaceous in France compares well with ours. Most of her zonal boundary markers appear to be useful, although her sequence of zones is not entirely the same as ours and her age assignment differ from ours. For some species, she described ranges which differ from those found during our investigation. Part of these discrepancies may be the result of different species concepts with regard to some of the taxa. For the Cretaceous zonations mentioned above, only appearance levels of taxa have been used to define the zonal boundaries. In 1973 Roth made a zonation based on material from Leg 17 of the DSDP. He also used last occurrences of taxa to define zonal boundaries. Some of these last occurrences we found to be clearly younger than reported by Roth. Therefore some of his zonal concepts are revised. Bukry (1973a) published a zonation for the low-latitude Upper Santonian

10 to Maastrichtian, which appears to be almost identical with Roth's zonal scheme. From the zonations for the Middle and Upper Cretaceous mentioned above Bukry (1974) compiled a new one, which suffers from the same disadvantage as the zonation of Roth (1973). Risatti (1973) proposed a detailed zonation for the Campanian-Maastrichtian interval meant for local use in the Mississippi area. Most of the markers he used could not be recognized in our material. The zonation Thierstein (1974) made for the Albian-Santonian interval in the Indian Ocean appears to be so well recognizable in our samples that it served as a basis for the zonation in the Albian-Lower Coniacian interval, but in some instances we chose other markers for zones which closely correspond to those of Thierstein (1974). The zonation of Martini (1976) compares well with our zonation for the Campanian-Maastrichtian, though not all of his zones appeared to be useful. In 1976 Thierstein published a detailed zonation for the Lower Jurassic through Upper Cretaceous. Most events he recognized in the Middle and Upper Cretaceous have been found in our material as well. Another zonation, partially based on the sequence of EI Kef, has been established by Sissingh (1977). Sissingh's species concept of some markers evidently differs from ours, which is one of the reasons that his zonation is different. Another reason is that Sissingh also incorporated last occurrences as well as many first occurrences, of species not used for our zonation, to define his zonal boundaries. Finally, during the Mid Cretaceous Events Congress (Nice, 1976) Manivit et al. (1977) compiled a zonation for the Albian to Turonian. This zonation, which differs only slightly from the one of Thierstein' s (1974), is the same as the one used in our paper. The subzones based on last occurrences in this 1976 zonation are not repeated. This short review of Upper Cretaceous calcareous nannoplankton biostratigraphy does not include all papers published on this subject. Other publications such as those of Radomski (1967), Bukry and Bramlette (1970), and Perch-Nielsen (1972) are of importance for some parts of the Upper Cretaceous. The maximum diversity in calcareous nannofossils in the Upper Cretaceous has resulted in a complexity of taxonomical problems, because of different species concepts of the various authors. This may explain part of the variation in proposed zonal schemes. The ample choice amongst index species that may be used as zonal markers explains the other part of the confusion.

11 Studies on the evolution of Cretaceous calcareous nannoplankton have just begun. Bukry (1969) indicated some possible evolutionary trends in the genera Vagalapilla, Pontilithus, Corollithion, Bidiscus, Cribrosphaerella, Broinsonia and Gartnerago. His observations were based on electron micrographs and some of them are hard to recognize under the light microscope. Lauer (1975) gave a detailed typological description of evolution in the family Arkhangelskiellaceae. After measuring some parameters considered to illustrate Lauer's ideas, some of the changes he reported could be confirmed, though in less detail. Prins and Sissingh (in Sissingh, 1977) described evolutionary trends in the genera Reinhardtites and Ceratolithoides. The lineage in the latter genus was outlined already by Verbeek (197 6b); it is described in more detail in the present paper. Recently, the first few papers appeared concerning problems of preservation and paleoecology. Hill (1975) studied the solution resistance of Cenomanian calcareous nannofossils. Outstanding studies about the types of preservation of Cretaceous calcareous nannoplankton have been carried out by Thierstein (1976), who published long lists of taxa the elements of which are either solution-resistant or easily dissolvable. Thierstein (1976) also considered the paleoecology and paleogeographic distribution of many species. One paper on this subject by Reinhardt (1973) had appeared before. He suggested that many of the changes in the Turonian calcareous nannoflora were the result of a decrease of the temperature. The samples were prepared according to the settling method, in which the fraction that settles between two and fifteen minutes is used for observation. For permanent mounts Canada balsam was used, and for mobile mounts the viscous oil Wonderolie (Castor oil). Samples selected for SEM micrographs were sometimes treated with a sonic cleaner for about ten minutes at a moderate vibration frequency. Results obtained with this method appeared to be hardly better than the attempts to clean the fossils with hydrogen peroxide. For SEM preparation, the material was studied in reference to a copper grid permanently mounted on a cover glass (Moshkovitz, 1974). In the light microscope, the liquid MIBK was used as an evaporating mounting medium (Hansen et al., 1975) instead of alcohol which evaporates too quickly (Moshkovitz, 1974). Routine study was carried out with a Leitz Orthoplan light microscope.

12 The SEM-micrographs were made with the Cambridge Stereo Scanning Electron Microscope at the Laboratorium voor elektronenmikroskopie of the University of Amsterdam. All samples are stored in the micropaleontological collections of the Department of Stratigraphy and Paleontology of the State University of Utrecht. ACKNOWLEDGEMENTS The author wants to express his thanks to all who made this dissertation possible. First of all he wants to thank his parents for their great interest and support during his study. He is much indebted to Prof. C. W. Drooger and to Dr. P. Marks for their continuous, valuable comments and suggestions and for providing the samples of the collection of the Department of Paleontology and Stratigraphy of the State University of Utrecht. He is grateful to Mr. B. Prins for assisting in taxonomical problems, to Drs. A. A. H. Wonders for furnishing the planktonic foraminifera data and to Dr. R. R. Schmidt for discussing the manuscript and providing part of the samples. Thanks are due to Drs. A. J. T. Romein and Dr. K. Perch-Nielsen for cooperation and advice. His sincere thanks are due to J. P. van der Linden and P. Hoonhout for the careful drawing of the figures and the composition of the plates, to C. Bakker for assistance in using the SEM and to Mrs. C. van Vessem, Mrs. S. Wellerdieck and Miss H. Wynia for typing the manuscript. He thanks all members of the Geological Institute of the State University of Utrecht for the nice time spent there. The author gratefully acknowledges the financial support from the Netherlands Organization for the advancement of Pure Research (Z.W.O.).

13 The present zonation was established on sample suites from two longer sections and a shorter one. The longer sections are those of EI Burrueco (Southern Spain) and EI Kef (Tunisia). The short one is the section of Javernant near Troyes (Paris Basin). In order to correlate the proposed zonation to the chronostratigraphy the calcareous nannofossils in the stratotypes of the generally accepted stages of the European Middle and Upper Cretaceous were examined. (fig. 1). The planktonic foraminifera of the section in Spain and Tunisia have been studied by Wonders (1975, in preparation) and those of the J avernant section by De Vries (1977). The species in the range charts are listed in the same sequence as the composite ranges. ELBURRUECO The village of EI Burrueco is situated near the southern margin of the Guadalquivir depression north of the Betic Cordilleras. A location map of this area is given by Wonders (1975), who also described the planktonic foraminifera of the lower part of the section. From this area a chaotic mixture of blocks of variable lithology has been reported by Tjalsma (1971). The blocks range in age from Triassic to Miocene. The investigated section is exposed in such a block, which overlies a basement of gypsum deposits of assumedly Triassic age, at one kilometer NW of EI Burrueco along the road to Arjona. The total thickness of the sequences is 164 meters (fig. 2). At the contact between the gypsum and the lowermost part of the section a very thin clay layer is found with small idiomorphic gypsum crystals and Cenozoic foraminifa, which indicated that the section is allochthonous and has moved during or after the Tertiary. Fortunately, this movement did not disturb the succession of strata in the block. The lower 26.5 meters of the section consists of homogeneous, slightly greenish, gray marls. These marls are followed by 40 meters of pink coloured micritic limestones, in which no sedimentary or bioturbation structures were observed. Part of this interval is not exposed. The next 40.5 meters show an alternation of white and pink coloured micritic limestone layers, each layer being about 50 cm. thick. At the top of this alternation a 20 cm. thick unit consists of three hard

14 Z -' Ul ~ Ul UlO u~ WU'" W ='~Z -'" Z-W Ul 0.. Ul ZWZ W OZO ~ZLL Z >- W~ _ OLLO -,0-0 f- <9 I- :z i= o..f-z "'-'f- -f- ~ 0 ~o..~ "'-~ "'- f- Z2Z 2Z2 u f- UOZ Ul :>~~ W ~ -'zo :3 <to f--'''' Ul ~ZN o.."'n ~o..o '" f- U~ 0 0 LL Ul Z LL Z mayaroensis :::! Micula..'.t:.. A.mayaroensis f- murus I Racemiguembelina U ~ Racemiguembelina contusa I f- Lithraphidites '", Ul quad ratus / gansseri ~ ~ ~ 6.contusa u ~ _2.-_ -" '-.±. tricarinotq 6.gansseri ~ Quadrum ~ trifidum ~ calcarata ~ Ti g:~g~gg;g~g '" 0 Z ~ Quadrum - Z goth icum ~0.. Cerato/ ith oid es 2 acufeuss.1. ~ U --- " ventricosa f ~ G.ventricosQ ::;: 0 elevata ~ Broinsonia parca '" " I 0 T G.carinata Zygod iscus I I <: elevata / spira{is carinata I..t.. G.elevata I Z '" ~ Rucinotithus " c - hayii.- Z 0 <J) 0 f- carinata Z Micufa ~ conca va Ul Brai nsonia..t. G.carinata lacunosa concqvata -~-;- ± G.concQvata z~ Marthosterites primitivq 0- <JlJ_ furcatus ± G.primitiva sigali f l' Chart showing the correlation of the proposed zonation with the Middle and Upper European stratotypes and the planktonic foraminiferal biostratigraphy.

15 <fl w...j NANNOFOSSIL <L LIT HOLOGY ZONES L: «<fl ~ ~ ~ m. white 164 ~ 178 ~ Quadrum trifidium m. pi nk and white m red 234 ~ Quadrum gothicu m m. pi n k and white Ceratolithoides acufeus S.l Zygod iscus spira/is 303 ~ m 290 poi n k 292 ~ ~ 293 ~ ~ ~ ~ ~ ~ 313 ~ ~ ~ Eiffellithus 315 ~ ~ turriseiffeli 317 ~ ~ ~ 26.5m. 319 ~ ~ grey green 321 ~ ~ ~ 323 ~ 415 ~ scosphaera col urn nata 414 ~ ~ ~ Predi 411 V V V V V V Om. I ~-: <::~-"J 5 and t.-..-::--j marl kvvvvv~ gypsum [I--,ill marly, :... limestone Lithological column of the section of El Burrueco (Southern-Spain) showing the location of the samples. Marly limestones in the section include indurated marls.

16 ~~~~WWWWWWWWWWWWWWWWWWNNNNNNN NNNNNNNNN ~~-~NN----~-OOOOOOOOOOWWWWWW~ ~~~mmmmmm ~W~~W-W~~W-Ow~~m~~WN-O~~~WNO. N-OW~m~NO XXXXXXXXXXXXXXXXXOXOXXXX XXXX xxxxxxxxx g O++++XOO+OOOO+OO.O+O , X+OO XOX '". '" W '" '" '". 0 X X X o X Watznau61ria barnesae :oxo :0 V ~ (J) ~ a I ~ ;!- 0 ~!- "- Watznaueria col77ml.lnis C claqe/osphaera n7arg&re~ Vt!!l(shine//a crux P.arhabdolithus emb~rgbr; Stsphanolithion /dh'icf:ei l1rdarudosph4er., bigelowi Bidiscu$ rocatorius A/feJnivice//a pemtnat'p/dea Watznaveria biporfa - -~ R.hagodlscuoS ~$p-ii;:: _ _- Zo/godlscus eleg8ns o Lithraphidites carnio/ensi$ : ~;:;:;;:a:':t~u;s:~7;.' 75s --~~---~ crvcit!!"l/ipsis Nannoconus cuvfllieri truihi Mark..aliws c;rcumrddiatus + crt!!t:arhabdus cr~nul.tus R.h41godiscus spiendens zygodiscus dip/ograrnm#s _..- -jioqi~rh--;;bd;,;s-d7et:zmannij Tegumentum s:tradneri R.l.Icinolithus irr~gulari$ + Chiastozygus /1~~r8rius Poa'orhabdus decoru$ o Cribrosphaer",ll", ehrenbergii ---- Vdk.shinella angust~ ~hagod;s'cus 4ngvstus TrAn o/ithus orionarvs Llt-hdstrintls ~/orb/is H~vesitt!'s. Ibien,sis Octopot:1orhabdJls B;scutum const4ns Bidiscvs Flabelllt6$ ignot"us biroraminus decussat:us Corol/ithion achlllosum Prediscosph~~r6 columnata Hs/ic:olithus trabec:vlatu,5 Podorl1abdus coron~dvent:is Prediscosphaera.spinosa corollith;on signum Cret:arhabdus lori~i + I\) N" ~ 0"- ;;-

17 'Ij qq" '" rt..., c;.: I=' g. ::l ;. (1) ("> e. ("> e; (1) 0 r;; ::l., ::l ::l 0., '"' 0..., S ;. (1) '" (1) ("> rt o ::> t:! tp I='..., 2(1) ("> 0 V; 0 I=' ;. (1)..., ::> C/l '0 e;. 2- ~r~rrr.lprflt;jlc;.o::.".c7/.a..., Pol'lcosrel/a sp. Scapho/ithes sp. 8roinsonia hilfa... ZVgodisCMS l77iniltlus x x EirFt!!/litfrus lurriseiffeli ---- earrnerago sp. Z/f!?Odiscus acanthw$.. Chiastozygus alt7phipons.. AhmveJ/erLl'I/a regul6rls Microrhabdu/vs belgicl/5 Coroll/chion exiguul x x Prt*alscosphaera cretscea... Microrh~bdwlu.s decoratu$ Cora/lith ion? comp/ecum C'flindr.alithus biarcus Gdrrne'r~go obllquum R.einh.ardtites Lith.sfrlnus grilli 6l."'~drumg~rt;nlilri -... Ahmwe/lerolla octor.ad/a"t.a brooksii + CI/Jlndrallthws serratus Calculites obscurus 9 roup o a )( ::0 ::0Elfft!'lIithu$ exlltjlus + + Kamptnerius tat>uldtvs + Marthasterites inconspleuus Lucianorhabdus scot:us ::0 ::0 Marthasterites Tvrcatus Prolatipatella multic,arinafa Broinsonia furt/va a Mictda decwssafa.;0:::0::0 - -:::0 Sroinsonia /.cunos.a Quadrum quadratum. + + Micu/a concava ChidSt:OZygvs interruptus - Ruelno/il:hus halfli Ve/(shinella bochot:nlcae _ Luc:ianorhabdus arcu.actts R.uadrttm nltldum Reinhardtites /71iniporvs -- R,hagodiscus renirormis ZVgodlscussplra/ls Ltlci.-,norhabdu$ ciilveux!! -- Cribrosphiilere//a eircwla --._- + + "; Broinsonia parca - - cj;'c/age/osphaera rotac/ypeata Kamptnerius magnlricus R.einhardtit6s anthophoru.s - Arkhange/sk/ella speci//.ata Cerato/ithoides DCU/<!!t/.$ 5.1. Quadrum gol:hicum + + A rk..h.ange/skje//a c mbirormls -. Crihrocorona,galliea Quactrum trifiaum 1O:t:~(Jl!DN[j::jO:::NCPtO;;:;--'WUrO:::(ll~CD:::O~(JI;i~e;, r:::~~::j~olidui-' :t.: (; A en f\).o, 00 ~ J: ~%lnc:teterminable ~~WWWWWWWWWWWWWWWWWWNNNNNNN NN~NNNNNN N N N N ~ --' --' ~ ~~~~~~~::jul~~og ~g~~82og~~f~~~~ ~~~g~~~~~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ SAMPLES f-' -...J

18 micritic grey limestone layers alternating with two layers of fine red-brown sand without calcareous nannoplankton. The overlaying unit is a 3.5 meters thick red micritic limestone, grading into a 17.5 meters thick alternation of pink and white limestone layers of about 50 em. thick. The top part of the section, which follows this alternation, is composed of 36 meters of white micritic limestones of which 5.5 meters are not well exposed. The calcareous nannoflora of the El Burrueco section is rather rich. Some one hundred species were recorded (fig. 3). The preservation of the fossils is generally rather poor, because of overgrowth with secondary calcite, especially in the upper part of the section, which consists of limestones. There is no relation between the colour of the sediments and the preservation of the fossils. Six zones were recognized. The lowest five meters are assigned to the Prediscosphaera columnata Zone. In the overlying 21.5 meters of the lowermost marly unit the Eiffellithus turriseiffeli Zone was recorded. This indicates a Late Albian to Early Cenomanian Age for this unit. The same age assignment was given by Wonders (1975). In the next higher pink limestones unit the Zygodiscus spiralis Zone and the Ceratolithoides aculeus Zone were recorded, which allows an age-assignment of the limestomes to the Late Santonian and Early and Middle Campanian respectively. The Zygodiscus spiralis Zone was recognized in the lower 15 meters of the unit. The Ceratolithoides aculeus Zone, which altogether covers 32.5 meters of sediment, continues into the next higher unit consisting of pink and white marls. The following zone, the Quadrum gothicum Zone is represented in the next 5 meters of this unit and allows a correlation to the Middle Campanian. The rest of the section, 85 meters, is assigned to the Quadrum trifidum Zone. The age determination of Late Campanian only is mainly based on planktonic foraminiferal evidence. There are zonal intervals missing from the top of the Eiffellithus turriseiffeli Zone to the base of the Zygodiscus spiralis Zone, and between the top of the Zygodiscus spiralis Zone and the base of the Ceratolithoides aculeus Zone. Thus sediments with an age from the later part of the Early Cenomanian to the Late Santonian and others straddling the Santonian - Campanian boundary are not represented in the section. The town El Kef is situated about 145 km. SW of Tunis, the capital of Tunisia. The area around El Kef, well known from the detailed work on the 1 : geological map by Burollet and Sainfeld (1956), is very

19 well exposed. In the region around El Kef three major lithostratigraphic units can be recognized. West of El Kef we find thick series of marls and limestones with an age ranging from Aptian to Eocene (Lutetian) with in their center a large body of gypsum deposits of assumedly Triassic age. South of El Kef terrestric sediments are found with an age from Oligocene to Recent. In recent years Salaj (1974) published details on the biostratigraphic succession of the planktonic foraminifera. Calcareous nannoplankton biozonations on the interval from Cenomanian through Maastrichtian of the Kef region have been made by Verbeek (1976b) and Sissingh (1977). Verbeek's paper contains a preliminary report of the zonation presented in this paper. The planktonic foraminifera of the samples used have been investigated by Wonders (Wonders and Verbeek, 1977, Wonders, in preparation) to obtain a first order correlation between the zonations on planktonic foraminifera and on calcareous nannoplankton. o fffilc/.i <fill' / go I I / /./~,J, ( \,- y...j.., "C 'y - - """v. /' \ i N t " 1"' = Triassic C= Cenozoic I = Cenomanian - Lower Santonian II = Upper Santonian- Lower Campanian ill = Middle Campanian-Danian = fault = = road r-o = sampled section

20 F or the establishing of the zonation three sections were studied (fig. 4), which together comprise sediments ranging in age from Middle Cenomanian through Early Danian. 56 samples were used from the total succession of about 2800 meters. The samples of the sections of Kat el Hamra and Oued Zerga were taken by R. R. Schmidt. The third section was sampled by P. Marks in the neighbourhood of EI Haria during an excursion of the Sixth African Micropaleontological Colloquium (1974). The calcareous nannoflora of the three sections is rich, though elements are sometimes overgrown with secondary calcite. The best preserved floras are found in the intervals in which limestone layers are absent. 117 species were recognized in the entire composite section. The flora is dominated by Watznaueria barnesae, Eiffellithus turriseiffeli, Prediscosphaera cretacea, Eiffellithus eximius and Micula decussata. Because of the long time interval covered by the entire section, the sequence seems to be very suitable to trace possible evolutionary trends (see chapter on evolution), the more so because no evidence was found for reworking. The section with the oldest sediments is in the Kat el Hamra: it measures about 550 meters. The lower part of the section (about 300 meters) shows an alternation of grey marls and brown-yellow limestones; the limestones become more frequent upwards in this lower part of the section. The upper 60 meters consist of limestones only. In the upper part of the section the limestone layers disappear. There are no outcrops between about 125 meters to 50 meters from the top of the section. In the section of Kat el Hamra five zones can be recognized (fig. 5). The lower 125 m. are assigned to the Lithraphidites acutum Zone and the next 50 meters to the Gartnerago obliquum Zone. The thickness of the three overlying zones, the Quadrum gartneri Zone, the Eiffellithus eximius Zone and the Marthasterites furcatus Zone cannot be given with certainty, because the two boundaries between these zones are in the limestone unit, of which no samples were available and in the unexposed interval. At the base of the Kat el Hamra section the Lithraphidites acutum Zone was recognized, which means that the lowermost sediments have to be assigned to the Middle Cenomanian. Micula decussata, which is commonly reported to occur from the middle of the Marthasterites furcatus Zone upwards, was not found in the section. Therefore the uppermost sediments of the section are assigned to the lower part of the Marthasterites furcatus Zone, which has been correlated with the Lower Coniacian.

21 I I CENOMANI AN TURONIAN ICON. STAGES : I 0",!1:o Lithraph..Q.~ a uadru"!. Eiff~lIl:thus I ;::Q ~~ acutum ZONES ; a,..tn~,..j exlmlus 2.; 3' Ii T I I II 11111:r X 0. ~imi I -... I I I I I, I LITHOLOGY y A ~3 0> I I I I /1 I I Ilil,,1,I uo 0 uo 0, '", ;! '- '" 9 0, 0, 0,.; 0> 0 -:-... l.oljl.u101...,c.lo o~ ;:;;;:;~li ~o; ;;; SAMPLES Watznauer/a.i....'. cl.icllgosphafalra vek.shinella.'... P.-rh~bdt7/;thws.1 Si:~ph.anoJithion Braarwddsph,a~ra BidiSCW$ W.3tzn.ueri8. R,hagodiscus Zygodiscws elegans LithrJphidit;es Cretarhabdu$ Cretarhabdus + +. Crwcle//ipsis Nannoconu$ truitt;. a + Marl(a/iu.s Cret~rhabdus cr"'nu/atus Rh.agodiscus + +' Zygodiscus PQdorhabdus ChiascQzygus.. Podorhabqw$ decorw$ Rhagodiscus angt..'stus rranolithv$ orionatw.s Biscwtum... +X_o_ X Bidisews.. F/ab~/lit~s. Corollithion achyloswn1 1 Helicolithus tr.sbecu/.stu$ I... Podt7rhabdwscorOn4!1dV8ntis Broinsonia signata.... Prea'iscosph;I#~ ra i. Cretarhabdvs Lwci"'J1orh,;,bdu$ cornpacrws. Broinspnia Cribrasphaere/la I! I X++..0 XO"'X EiffelJithw$ turriseil 41li... i Chiasfoz/f'!7us... LithrlPhidifes.1, Corallithion? completum >... Lich.asfrinus... fi(vadrum g.srtneri.. Ah"n".llflrel/6 R.~inh3rdtit~s Cl(lindralithv$ c~/c'ulitt9s ob.scwrws growp. EiFr.//ithus KJmptn#riws Lllci~ncrhabdw$ M~rthlst:~rite$ XX XXXXX XX XXXX XX X Wat;znav~ria barnesa communis.1 SOI/4sitf!ls horticu$ margart9/i crux Pol'f'coscelJa Zlfgodiscus i'" ManiviteJ/a,mberSTerl /arfittei bige/owl rot~t:orius pej77l77otoidea pipor/oj asper carnio/ens-is conicu$ surirellvs eh/ast c:ircj.(/'nradiatus splendens dip/~grdmmus di~tz",41nl1ii li~erariu$ Lithastrinw$ Flora/is cons'c,;,ns Ignctws bift7ral17inws spinosa Corallith;on signum loriei enormis pelta.p. Scapholithws sp. I 1 Broinsonia J~til z godiscws minimws Zlf9oe:{iscU3 Jlcanthws al77phipons th~ta.: Microrhabdulus be/gicus acutum Microrh41bdv/us d~coratus Cylim:;ir,~/ithwsbi.,rcus t3j1rtl7er..ilgo obliquum grilli octor,adi3/'.6 brcol<sii Sti'rr6~US ximiws ~Jbulatv$ m.lle6~rrni5 inconspicuus Ll<'ciilnorh~bdwsSC'l7tu.s rurc.ltus m",lt;c,.rindta 8r_ilrwdcsph~.r. cf.b. discwl.., M~rth.$t~rir.s Pro/..,tipiltellil c;..<:;10. '" '" <; '% Indeterminabl. N.. N.... O"."-I... ~,"0 Composite section of El Kef - Distribution chart of the calcareous nannoflora in the sequence of Kat el Hamra..,.

22 o. + o +++..f _ Wat"zn8U#1ri~ b~rn~sdt! WatznaLleri", communis Sollasitl$ l1ortict/5 c'ic/agelosphae.na Vtlk.:shinr/)4!J crux Pdrh4bdo/ithHs x 0 + V A... Q) f\) I\) ~ ~ ~ ~ -; -J fflarga;oe// embeorg ri st:l!!ph~u70/;th;on Ilffittei BrlaTua'ospI74 r., bigll/owi I'jdiSCU$ rot3torlu$ M3f1ivit,,/la plmmltoidt:'4 WatzP4ut:'ria biporc41 ZY90discus 116g.lns Lithrlphidit..s Creotarha/:>du$ cjlrnio/'n:!lls con/eus' Cretarh.llbdMS stlnr.jlus Nanl7oconus trwitt:i Mlfr1(,ius circumr6d/.jtu$ Crec4rhabd"s ctenul",t:ws Rhdgodisctls sp/lndlns zygodisctls dip!ogrlmmus Chi4:5Cozygus Podorhlbdws CribrosphJler.llet Rh_godiscus Trdn"lithvs lit'ter,aritls Of!!1COrkS 6ngustuS' orion4tus 1.Ito_strinu$ florllis Crlt>r".sphl~r,// B/scutum Bidi,scus Helicolithus Podorhlbdus 6hrl1nb,rgil pelt const4ns Ignotus Pr"diS'cosPh~"r.ll Coro//ithion tr b.cu/~tu:s corofljllt: y.ntis signum Cref4rh.-J>du3 lori_i Luci.#norh~bdus,spin OS" cornp6c!:w..s

23 "I:I <1'" a- '" C1> () 0 ~ S C1>'O ::> 0 n ftl ::t' '" o C1>..., ori '" n ft g. N::> ~ 0 OQ..., ~ g1 ~C1>..., I 9- '"~ cr: ~ 0' ::> n ::>" ~ ọ.., rt ::>" C1> n eo. ~C1> o e tl ::> o '.., '" S' N rt W ::>" C1> EifTeJ/it:hus Z/lgodiscu.s Chiastozygu.:r. Ahmlle//ere/Ja MicrorhabduJus Pontilithus Cora/fithion "'00 0+'" X Micrornabdulws.. C'I/indrAlithus 6artnerago Lit:h4strintls Q.uadrumgartnen... Ahmwt!'/Ierdllla.. R.einhardtites + Cillindriil/ithus X 0... XXo X... ox'"... Eiffellithu$ eximius Kamptner/us Lucidn<7rhabdtls... Marthasterites Lucianorhabdus o M4rthasterites... Prol4tipat:ella Broinsonia rurt;iva Broinsoni... 6l."Iadrwm"1p.34r.3t'um.. Poll/cIa Micwla Chi4lsco.xygus R.wc/nolithws. Vel(shin_lIa Lucianorhabdws 6l",.. Reinh4rdtit~s Lucian.orhapdus.. Rh.-aodiscvs Zygodiscus Lwcianorhabdv$ BroinsoniJiJ - C cjclgelosphaera. -- Kamptnerius -...,.!:?..,..,.;J. u ~ turris-eiits/i <ilc8n~hus 43mphipons r~gu/.i1ris be/gicjls obliquic.3ncellatus exlguum... +X X 0 0 X oox X Prli1discospht!1cra cretace.3 ~Ol~ Ui 0; b- e; "l b- t. to - a> 0 0 io '" '" ~~ '"~ www ww w W A A AAA A '" ~"'w '" '" '" '" '" '" <D ~ WA'" a> <D "'''''' "''' ~ W A"'''' " CribrospheereJI4 Calculites dt!'coratus biarcus ob/i'1uum grilll octorjldi.at:a brooks,,! serr,:,tus ob..5cwrus group tabu/3t:u.$ tn~/~rorm;s inconspictltls scotus TtlrcJltus I71tdticarin3t:a X Micwla d~cussat8. lacunc>s.a dolithus sp. concav8 inf6rrup{;ws h3,!ii fi'/7chotnicae arcvatus drwm nitidum miniporvs 9u4driridus rf!jniforrnis spir.-lis c_'f~uxii circula pitca rotac/ypeata m4gnif'icvs ReinhardCites Jlnthophorus Ark..hangl!!lskiel12 sp~cil/.ata Cer<Jtolit:hoid<!!s act-deus $./. U. %!ndet-erm inabje SAMPLES

24 !fir ) I CAMPANIAN : I, MAASTRICHTIAN STAGES "'0, Q~'.., ~[ Quadrum llithraphidites Micula z ~v: ~~ trifidum : quadratus murus." I ZONES Q~. (Il' I ~ '" II ';'1 ";~, ~~~~~:;I,II',I, 1 1/,1, (,1;'1 1,',',',I I, II '1'1 I,ll I H H H H HI,I /11 111"1 ", 1,1"1 1,',' (J) I, II, '~H H HI) I I /,I I, 1)1)1 ~ 0, '", i' '" <5 tt 0 (J) i' I 'II 0 0 1\\ I \\ '" 0 g:3 [ 0 i' I, I I i' " - ~ '" ",,,,,,, COOlCDOl i)i '" '" "'''' "''''''' "''''0 000 SAMPLES - '" w" 0 low f\)~% '" -.. "''''0 :u X 0 +. LITHOLOGY :u V A XXXX X X X XX XX XX XXX X:u:u watznaueria barne-.s~- :u ~=:~~ae~;;~~a:~;;;~ - :u Vekshinel/a crux ---~ rp.ir:habdoliihus emb~rger~ " !. :u Stephal7olithion laffittei _., "cre tarhabdu$ schizobrjclihilus ~:~;:;:;%:::-::J~;e/~~~!. --~nivit;;i7a-pemma't;oidea- --- _..-._-- - -Wa'tz:m'verfaNpC;rf:; _ Zv..godisc~=-.!:/~gan.= :u:u r---zfthraphidices ci'lrnio/ensis._ Cr~tarhabdus surirel/us ,,--- :u Mark.aJius cj rcul7lr.a~ :u R.hagodiscus splendens + z god/scws - ~:~:~~:~~~:T;~:~e;;,:::~ + :u ~._ ~.._--, _ :u.. --_..~ - -!. Rh~godiscus + + Tr<ilnolithu$ + Bisewtwm ~_._- --- ~ ~--- Pradiscosphaif}ra _.- ~- _-----=== :u:u Cribrosphaerd//a pelta _ Zlfgodiscus :u:u EiFFel/!thws t:urriseiffe/! -. Zl{~odi.sc#s '-Ch;a~tozv.i~S4I?'1phipons :u:u -- Coro//ithion ooox + + XO OXO :u:u Prediscosph.aer.a cretacea lie/icolifhus :u Cretarhdbdus can/eus :u Cret:arha/;>dus crenulatus diplogr'iflmmus +:u:u Cribrosphatllr~!la ehrenbergii angt.lstus or/on~tus._- constans Bid/sews ignocws --- tr~becu/.gtt/~_ spinosa crat:arhjflbdus /orlt'!'! Bro!nsonia Sc~phollthus norm!s sp. mfnfrnvs "c4nth~~ :u Ahm#e/lerella regular!s MicrorhabdH/U$ be/.!7icws exi'1uvl11

25 '" Ahmll,gJler~//a + + J?einhardtites C /indra/ithus CalcJ,(/it:es obscurus group Lwclanorhabcius Marthasterit.es I Pro/at/patel;';' /17ulticarinata ~ ljra.arua'osphacna Bro;nson/~ {"ure/va 8roinsonia 0+ +X + 0 X XO XX XX XX X MicuJa decwss-at:a X"'''' Cluadrum quadratuj?1 '" R,vcino/dhvs h.alf/i' - '" Luc;anorh~bdv.s 6?..u,drJ.ln1 r8nirormis -" "- Z'l.90discvs Lwcianorhooctus I(amptneriws '" - '" 0 Q.uadr«mgothicum '" perlorata 0 0 Lvci8norhal:>dws Q.UadrHmgariner; octor4a'iata broqj(s;i st!!rratus Eiffl9/Jithus t!!xlmiw$ J(af77ptnerivs tiilbulatvs.",,,, ma/etorl17is fnconspicuus Lucianorhabdu$ SCOt:U5 R...hagodl.s-cwS" 0 0 crlbrospha~r~//d Broinsonl3 0 0 C/fclagosphaerJl,/(einhardriros 0 0 cf. B.disculJ lacul10s3 Micw/a concavo Vek.shlne/l., bochot"ttico!lc orcu,;;,rws nitldvm qj-ladrihclws spir4/l/is cayeu.:.ocii circuja parca -- rorpc/t;peat:a magniricus anrhophorus Arl(hEngelsk,.iel/aspeci//<!It" ceratolithoides acu/eus W "''''

26 The section with the youngest Cretaceous sediments was sampled near El Haria. The lower 60 meters consist of grey marls, followed by 40 meters of alternating grey marls and yellowish limestones. Overlying this alternation, about 65 meters of limestones are found, overlain by another 220 meters of alternating marls and limestones, and again a limestone unit of 120 meters. The marls on top contain the Cretaceous-Tertiary boundary. For easy reference the section is drawn in fig. 1 up to the first limestone bed in the Danian sediments. The section was found to contain sediments, in which the Broinsonia parca Zone up to the NP 2 Zone are recognized, which indicates an age range from Early Campanian to Early Danian. The Broinsonia parca Zone is recognized in the lower 30 meters and the Ceratolithoides aculeus Zone in the next 50 meters of sediment. The Quadrum gothicum Zone was not recognized in the samples available from El Haria, but its markers were observed in additional material from another section near El Kef. The zone must be represented somewhere within the twenty meters of sediment between the samples AFN 183 and AFN 184. The boundary between the Quadrum trifidum Zone and the Lithraphidites quadratus Zone is located somewhere in the 220 meters of hard limestones between the samples AFN 190 and AFN 191. The Micula murus Zone was recognized in 140 meters of the marls. The presence of the NP 1 Zone is not based on nannofossil data, but on the recognition of the planktonic foraminiferal Globigerina eugubina Zone. JAVERNANT The village of J avernant is near the town of Troyes, South of Bouilly in the "Champagne crayeuse" of the departement Aube (sheet 333 of the 1 : 50,000, geological map of France). A detailed description of the area SE. of Javernant and of the exact location of the samples is given by De Vries (1977). The samples (Fr 1537-Fr 1547) were taken by P. Marks in the cuesta of chalky marls, which overlies clayey and marly deposits of the Albian. The total sequence is composed of four smaller exposures. The samples Fr 1537-Fr 1540 were taken with a sampling interval of 60 em. in an old quarry 1050 meters from the crossing of the roads D 188 and N 77; sample Fr 1541 comes from the embankment of the N 77 at this crossing, from a level about 8 meters above the top of the quarry. About 6 meters above Fr 1541, four samples (Fr 1542-Fr 1545) were taken in a quarry West of the D 188 and N 77 (coordinates X = 724.8; Y = 52.3) with a sample interval of about 1 meter. The samples Fr 1546 and Fr 1547 come from the embankment of the N 77 near the entrance of the village Villery (coordinates X =

27 I CENOMANIAN I TURONIAN S TA G ES Quadrum I Eiffel. gartneri ZONES exlmlus III I II X I I I I I.~ I LITHOLOGY Y /\ I 1 ~ 1 ~ 1 II 0> I 0 '",.;..;. l '" 3 0 ~ L--l.--J.;.... ~~~~ :;' ~~~ J. " "::I Q;t:n U. H ~u.u. ",,,, SAMPLES ",,,, :: "" ",,, "''' " " 7J rr ON'" "'" XX. '" X 0 X XXX X )( W~rzn,av.ria barnesae W~tznau~ria cojnmunis hortlcus cycjagelos,phaera m<:jrgare/; Vek...shinefla crux embergeri laffit:cei S"II.asit~s Parh_bdolit:hw.s Stephano/it:.hion Braarudosphaera i MinivitiJ/la I Watznau@r!" I Rh.agodiscus... I Zl{gOdiscus... : Llthraphidit:es..... conic-ws Cretarhabdus sur/rellus Nannoconvs Mark,.a/iws '1 I, Cretarhabt:iu.s!?hagodiscvs......, : Zl/gocii.scJ<'s diplogr.ammus PodorhabdtlS /itter.arivs Chiastoz gus,... Podorhabdus R.hagodiscu.s I I , Tr.anolit:hu$ orio17jitw$ I i, I I CJctopodorh;;p4us d~c(.;'ss,61ttls I Corollithiem I '. Helicolithus Podorhsbdus Brojnsonia i Predi,scosph4erd Cret:arhabdu.s Broinsonia crlj;>rosph~erella scapholithus X..oX X Ei#el/ithw$ thrriseifteli Zygodiscus Chiastozygu.s Z 9.::>discuschet'a 0'" 0... XXO ox Microrh4iJbdu/us... Gartnerago op/iquul17 I Lith.astrinws trucdrj.li71g.9rtneri Ahmu~ller~lla R.einh~rdtit:as C lindrclithu$ Calculites 00 Cret:c!1rhabduS' Ahmuellerells 0, bigf1lowi I Bidiscus roc8t:orius Lithast"i!?uS Bisewtu,.,., Bidiscvs EifT~l/ithu$ -'" - '" '" - '" " - "'" '". "'''''' 0" pemmatoidea biport:.a.3sper ~)eg.ans carnic'fensis trvit:ti circumraai"atus crenu!iii'tus'.splendens aietzmannij decorw$ angust:us ~/O,.a.//s consr.ns ign17tus <iichyloshm tr.abec~/.atus coron.dvt!1fltis signata spinosa Cor.::>I/ithion signum loriei 8normis pelt-a sp. ZygodisCHS 177inimJ.ls,acanthus amphipons regulans MicrorhabdulHS Ol9lgicus Predi.scosphaer. cret:ace., a'ecor3tus grill; oct:oradl.ata brooksii serr",tl-ls OOSct.I'rus9roup ex/mitis % r ndeterm in.ble

28 725.1; Y = 53.2) about 900 meters from the crossing, with again a sample interval of 1 meter. The stratigraphical interval between the samples Fr 1545 and Fr 1546 is not well established, but does not exceed a mere 10 meters. The planktonic foraminifera of the composite section have been published by De Vries (1977) and a distribution chart of the calcareous nannoflora was given by Verbeek (1977). The flora is dealt with again here because it is of great interest for the Cenomanian-Turonian boundary. This boundary interval is rather poorly exposed in the section of EI Kef and also in that of Fretevou (Touraine), the Turonian stratotype. The nannoflora is sometimes rather poorly preserved because of overgrowth with secondary calcite (fig. 8). Especially sample Fr 1539 contains such a small number of nannofossils that the observed species are listed without an abundance indication. Two zones have been recognized. The lower part of the section (Fr 1537-Fr 1541) is assigned to the Quadrum gartneri Zone. The absence of Lithraphidites acutum indicates that the lower part of the zone is missing, because this species has its extinction level within the Quadrum gartneri Zone. The upper part of the composite sequence is correlated with the lower part of the Eiffellithus eximius Zone only, because Lucianorhabdus maleformis, which species has its appearance level in this zone, was not found. The lithology of the Middle and Upper Cretaceous stratotypes studied in the present paper have been described by various authors. Larcher et al. (1965) described the Albian stratotype, Marks (1967a, b; 1968) the Cenomanian stratotype, Lecointre (1959) and Butt (1966) the Turonian stratotype, Seronie-Vivien (1959, 1972) and Van Hinte (1965) the Coniacian, Santonian and Campanian stratotypes, though the latter authors disagree on the location of the real Santonian stratotype. Romein (1962) described the Maastrichtian stratotype. The nannofloras and correlations of the stratotypes with our zonation are discussed in chapter IV.

29 The zonation is based on composite ranges of the species considered to be of biostratigraphic importance (fig. 9). All zones are based on entries and the names correspond to that of the entering species. To each zone an author's name is added, which indicates that this author used this zone (not the name) in this sense for the first time. The description of the zones is given in chronostratigraphic order from older to younger. The range chart is based on the data from the literature and the sections discussed in the previous chapter. For remarks on the other localities used to link the zonation with the chronostratigraphic scale the reader is referred to the next chapter. Prediscosphaera columnata Zone Thierstein 1971, nom. cor. Manivit et al. (1977) Definition: Interval zone from the entry of Prediscosphaera columnata (Stover) to the appearance of Eiffellithus turriseiffeli (Deflandre). Definition lower boundary: Thierstein (1971). Definition upper boundary: Thierstein (1971). Manivit et al. (1977) separated the small Prediscosphaera columnata from the larger Prediscosphaera cretacea, the latter species entering later. For this reason Thierstein's Prediscosphaera cretacea Zone has been changed in Prediscosphaera columnata Zone, though its scope remains the same, as Thierstein did not distinguish both taxa. Remarks: All species, except Broinsonia signata, which according to Thierstein (1973) would have their first occurrence in this zone, have been observed in our samples. They are: Prediscosphaera columnata (= Pre discosphaera cretacea in Thierstein (1971, 1973), Helicolithus trabeculatus, Podorhabdus coronadventis, Tranolithus orionatus, Broinsonia lata, Podorhabdus dietzmannii and Prediscosphaera spinosa. Of these, only Prediscosphaera columnata and Podorhabdus coronadventis have been found in the sections of the Aube. On the other hand a number of species not mentioned by Thierstein, as forming part of his zonal association: Lithraphidites alatus, Lucianorhabdus compactus, Cribrosphaerella pelta, Broinsonia enormis, Corollithion signum

30 I : I I ALBIAN I I CENOMANIAN : TURONIAN :CONIACIAN: SA NTON I AN I I I I I I I I I I I M I I I I U M : L : M I I U L :M I I I I I L I I U I I I U I L I M I I I I I I I I I I I I ~ c- :i;: :0 '" en, 0 "0. " -. og) n, 0;; ~:::. co 0_. o-~ C,,~ <00 co:::;: -'",," Oc c". 0-" 0 2:i;: c" (;j.~ "'~ ".-. " CO :::; -'0 "0 -.'" " ~ -" -0", ;~ 3:::: Co C". "'" 0-0", 0::' "" ~.~ '" C " "'c i::.:::: 0" 00 ~". 3 : Co :c. -'" c-, _.~ 3 ",'" "'0 i:jo -". "'c 3<0 00 C {JJ ;:;.- ::::r.n Q 0" C <D 0 '" '" " 0 '" '" '" -_ v - -.~ !

31 I I I CAMPANIAN I I I MAASTRICHTIAN I I I I U I I I I I I L M I I I U I L I M I U I I I I I I r, e- OJ ~ '" ~..0:::;: ~ 00 to", ~o,,;,- "'to "bo n~ 0" ~.c: o~ "0 3:S: 0-,,~ ~O ~O 0.0 ~.Q.. -'0. ~" --. " ~n ~~ o.~ n '" "'~ ~~ ~",,~ -'" 00 i.ii"o ";,- <:<: <:",,0. "'0 "'0 " (I);::;: '" " a Q '" '" Prediscosphaera columna ta 8roinsoni lata Cr;brosphaer~jfa pelt:a Coro//ithion Zlfgodisccus signu/71 minil'17vs Broinsonia enorm/s Lucianorhabdus c:ornpact:vs Lithr.aphidit:es alacus Vekshine/la EIHe/lithus angusta tvrriseifft9// Z'{godisCffS acanl:hus Rucino/itl71N, irregularis Havesites Chiast:ozl('gws Ahl77uellerel/a a/biens/s 8117phipons regularis Microrh<OJbdulws belgicus Lichraphidit:es acut-um Coro/lithion exlguultl PredisccN>phaera Microrhabdulus cret:acea decor.atus Cruciel/ipsis chiasta Coro/lithion? cornpletum Clf/indralithus bier-cus Gartnerago obliquwn1 L ithastr/nus grill! QuadrU!71 gartneri R.h8godiscus asper Ah;nwe//lPrel/a oct-orad/ara Reinhardt:it:es brooksii C;,dindra/iChus serracvs Ca/cw/ites obscvrws" grot.tp EifTelliz~hws /(amptneriws eximius tabu/atus Lwcianorhabdws Marthast.erit:es ffla/eformis inconspicwus Lwcianorhat>dus scot:us Marthasterlt:e.5 rurcatus Pro/ar/patel/a mull;.icarinata Broinsonia rwrtiv.a Micula deeussar-a Broinsonia /acwnosa Quadrun7 quadrarum Micw/a conca va Rucino/ino/ithus harti; Vek.,shineJla bochotnicae Lwcianorhabdus arcwatws Qwadruf77 nit-idwm R,einhardr-ites miniporws Lucianorha bdus qwadriridu$ Rhagodl'scus ronirorl77is zv90discus spira/is Lwcianorhabdu$ cavewxii Crit>rcsphaere//.a cireu la Lithastrinw$ Tlora/is _ Brcinsonia parca Clf'c/age/osphae/'a. rc'cac/vpeaca k:an7ptnerius magnirt'cws Reinhardtites anthophorus Ark:"hange/sk/e//a sp~ci//ata PodtPrhabdus coronadvencis CBrat.otitht?/des acu/eu$ s./. Quadrum gothicun7 Arkhang/?/Skiel/a cvlnbiforfflis Crit>rocorona ga//ica Quadrum trif'idum Lithraphidites quadratus ThQra cosphaera Opercu/ata Mark,a/ius Discolichina Lithastrinvs? /nversws spira/is st"r.3dneri Ceriltolithcidps arcu8tus Miew/a I'nurus _ Cerato/ithoides kamptneri Eirre/lithus p6ral/elus Chart showing zonation and composite ranges of stratigraphically important species recorded in the sections studies, in relation to the stage assignments.

32 and Zygodiscus minimus are present in the Burrueco section, but not in the Aube sections. Therefore it is likely that these species start their range higher up in the Prediscosphaera columnata Zone. Thierstein (1973) reported the appearance level of Broinsonia enormis and Corollithion signum even higher, in the Eiffellithus turriseiffeli Zone. It may indicate that the samples from the Burrueco section only cover the upper part of the Prediscosphaera columnata Zone, which part seems to be absent in the Aube samples. Vekshinella angusta has its last occurrence at the top of this zone. The lower boundary of this zone was not observed in the material studied. The upper boundary is in the Rotalipora subticinencis Zone of the planktonic foraminiferal zonation. The zone was recognized in the sections of the Aube (Villemoyenne, Montieramy, Courcelles) and in the lowermost part of the section of EI Burrueco. Age assignment of the upper boundary: in the Middle to Late Albian. Eiffellithus turriseiffeli Zone Verbeek 1977 Definition: Interval zone from the appearance of Eiffellithus turriseiffeli (Deflandre) to the entry of Lithraphidites acutum Verbeek and Manivit. Definition lower boundary: Thierstein (1971) Definition upper boundary: Verbeek (in Manivit et al., 1977). Remarks: Eiffellithus turriseiffeli originates from Vekshinella angusta by the rotation of the bars and the closing of the central area (see remarks on evolution). Eiffellithus turriseiffeli is defined here to have the longest bar making an angle of more than twenty degrees with the longer axis of the basal disc. In the lower part of the zone this angle increases sometimes to more than sixty degrees. Chiastozygus amphipons, Zygodiscus acanthus, Pontilithus obliquicancellatus, Ahmuellerella regularis, Microrhabdulus belgicus, and Eiffellithus turriseiffeli start their range in this zone. Hayesites albiensis has its last occurrence in the zone, which exit was used by Manivit et al. (1977) to subdivide the Eiffellithus turriseiffeli Zone into two subzones. Lithraphidites alatus is rather frequent though its blades are often narrower than described by Thierstein (in Roth and Thierstein, 1972). Bidiscus ignotus, Prediscosphaera columnata and Bidiscus cons tans are more frequent than in the underlying zone. Strong agreement exists to use the first occurrence of Eiffellithus turriseiffeli to define the lower limit of some Eiffellithus turriseiffeli Zone. Roth (1973), Thierstein (1974,1976) and Bukry (1974) defined the upper bound-

33 ary by the entry of Lithraphidites alatus. However, in our material Lithraphidites alatus was found to occur below the appearance level of Eiffellithus turriseiffeli. The species can therefore not be used to define the upper boundary. Verbeek (1976b) defined the upper limit by the entry of Gartnerago obliquum and Sissingh (1977) by the entry of Microrhabdulus decoratus. Both these definitions create zones which span a rather long time interval. The later proposal of Verbeek (1977, in Manivit et al.) is retained here which implies that the upper limit is defined by the entry of Lithraphidites acutum, because this species occurs earlier than either Gartnerago obliquum or Microrhabdulus decoratus, but after the appearance of Eiffellithus turriseiffeli. Moreover, by now a rather large distribution is known (Paris basin, Tunisia, Indian Ocean). The zone discussed covers an interval in which seven planktonic foraminiferal zones can be recognized. The lower boundary is in the Rotalipora subticinensis Zone and the upper boundary in the Rotalipora montsalvensis Zone. The zone is recognized in the lower part of the Burrueco section in Southern Spain, at Ballon, and in the lower part of the Theligny section of the Cenomanian stratotype. Age: Late Albian - Middle Cenomanian Lithraphidites acutum Zone Verbeek (this paper) Definition: Interval zone from the entry of Lithraphidites acutum Verbeek and Manivit to the entry of Gartnerago obliquum (Stradner) s.s. Definition lower boundary: Verbeek (in Manivit et al., 1977) Definition upper boundary: Manivit (1971) Remarks: The lower boundary of this zone is drawn at the first occurrence of the marker species and of Corollithion exiguum. Other species, which appear in this zone are Microrhabdulus decoratus, Prediscosphaera cretacea, Corollithion? completum and Cylindralithus biarcus. Prediscosphaera columnata, Lithraphidites alatus and Cruciellipsis chiasta disappear in this zone. Rhagodiscus asper becomes rare. v The entry of Corollithion exiguum has been used by Cepek and Hay (1960a, b), Manivit (1971) and Roth (1973) to define a comparable zonal boundary. Manivit (1971) reports this entry at a level higher than that of the appearance of Gartnerago obliquum and her zonal boundary therefore cannot be the same as the lower boundary of our Lithraphidites acutum

34 Zone. Unfortunately Corollithion exiguum is too rare to be useful as a zonal marker and as a consequence the correlation of the lower boundary of the Lithraphidites acutum Zone with the lower limits of the Corollithion exiguum Zones of Cepek and Hay (1969a, b) and Roth (1973) remains somewhat uncertain. The zone discussed incorporates the upper part of the Eiffellithus turriseiffeli Zone of Verbeek (1976b) and the basal part of the Microrhabdulus decoratus Zone of Sissingh (1977). The last occurrence of Cruciellipsis chiasta was used by Manivit et al. (1977) to subdivide the Lithraphidites acutum Zone into two subzones. The lower boundary of the zone can be placed in the Rotalipora montsalvensis Zone of the planktonic foraminifera zonation. The zone has been recognized in our material in the upper part of the Theligny section of the Cenomanian stratotype and in the lower part of the Kef section. Age: Middle-Late Cenomanian. Gartnerago obliquum Zone Thierstein 1974 Definition: Interval zone from the entry of Gartnerago obliquum (Stradner) to the entry of Quadrum gartneri Prins and Perch-Nielsen. Definition lower boundary: Manivit (1971). Definition upper boundary: Cepek and Hay (1969a, b) emend. Manivit et al. (1977). Remarks: Gartnerago obliquum and Lithastrinus grilli have their entries in this zone. Verbeek (1976b) incorrectly placed the first occurrence of Lucianorhabdus cayeuxii in the Gartnerago obliquum Zone, but after restudying the samples it became clear that the forms earlier assigned to Lucianorhabdus cayeuxii are fragments of large specimens of Lucianorhabdus compactus. Manivit (1971) defined the upper boundary of this zone by the first occurrence of Corollithion exiguum, but this species has been found in sediments older than the entry level of Gartnerago obliquum. The Gartnerago obliquum Zone of Roth (1973) is not comparable with the zone used here, because Roth (1973) defined his zone as the interval from the exit of Marthasterites furcatus to the entry of Broinsonia parca. Micula staurophora of Thierstein (1974, 1976) must be placed in synonymy with Quadrum gartneri. Therefore our zone is identical with the Gartnerago obliquum Zone of Thierstein (1974, 1976) with the same name. Our zone covers the upper part of the Microrhabdulus decoratus Zone of Sissingh (1977), which has the same upper limit as our Gartnerago obliquum Zone.

35 Manivit et al. (1977) did not include the Gartnerago obliquum Zone in their zonation, because the authors could not reach an agreement on the distinctness of the lower limit of this zone in Upper Cenomanian sediments. They disagree whether or not Gartnerago obliquum could be clearly distinguished from the very rare Gartnerago sp. and Gartnerago diversum found in Albian to Middle Cenomanian sediments. However, since, according to the present author, distinct differences do exist between Gartnerago diversum, Gartnerago sp. and Gartnerago obliquum, the entry of Gartnerago obliquum is considered to furnish a distinct biostratigraphic datum level in the Upper Cenomanian. Both the lower and upper limits of the Gartnerago obliquum Zone are within the planktonic foraminiferal Rotalipora cushmani Zone. The Gartnerago obliquum Zone has been recognized in the lower part of the Kef section and in the lowermost part of the section of Fretevou, below the present interpretation of the type section of the Turonian Stage (Verbeek and Wonders, 1977). Age: Late Cenomanian. Quadrum gartneri Zone Verbeek 1976 Definition: Interval zone from the entry of Quadrum gartneri Prins and Perch-Nielsen to the appearance of Eiffellithus eximius (Stover). Definition lower boundary: Cepek and Hay (1969a, b). Definition upper boundary: Verbeek (1976b). Remarks: In the section of Javernant (Paris Basin) Ahmuellerella octoradiata, the Calculites obscurus group, Cylindralithus serratus and Reinhardtites brooksii appear in the upper part of this zone. In the Kef section the latter three species have their entry at the base of the overlying Eiffellithus eximius Zone and Ahmuellerella oetoradiata occurs for the first time in the Marthasterites furcatus Zone. Lithraphidites acutum and Rhagodiscus asper are found to have their last occurrence in the Quadrum gartneri Zone, though Thierstein (1973) reports a much higher extinction level of Rhagodiscus asper in the Upper Turonian. Bidiscus ignotus becomes abundant. In the upper part of the zone some individuals of Eiffellithus turriseiffeli show a longer bar, which is only partially rotated, not exceeding and angle of twenty degrees with the longer axis of the elliptical basal disc. Quadrum gartneri is the same species as Micula staurophora of Stradner (1963), of Manivit (1971, France) and of Thierstein (1974, Indian Ocean,

36 1976), and Tetralithus pyramidus of Cepek and Hay (1969a, b) and Micula decussata of Roth (1973) from the Pacific Ocean (Manivit et ai., 1977). As a consequence the lower limit of the Quadrum gartneri Zone can be recognized worldwide. The upper boundary of the Quadrum gartneri Zone has been defined in different ways. Cepek and Hay (1969a, b), Manivit (1971), Roth (1973) and Thierstein (1976) defined the upper limit on the basis of the first occurrence of Marthasterites furcatus. Afterwards it became clear that a finer subdivision could be made. Thierstein (1974) used the entry of Kamptnerius magnificus; Verbeek (1976b) and Manivit et al. (1977), the appearance of Eiffellithus eximius, while Sissingh (1977) used the first occurrence of Lucianorhabdus maleformis. In the present paper the upper limit is based on the evolutionary appearance of Eiffellithus eximius from Eiffellithus turriseiffe li. The lower boundary of the zone is correlated with some level in the Rotalipora cushmani Zone and the upper boundary is in the Praeglobotruncana helvetica Zone, so that the entire "Zone a grandes globigerines" is within the limits of the Quadrum gartneri Zone. The zone is recognized in the sections of EI Kef, Javernant (Paris Basin) and in the Turonian type locality at Fretevou (Touraine, France). Age: Late Cenomanian-Early Turonian. Eiffellithus exirnius Zone Manivit et ai Definition: Interval zone from the appearance of Eiffellithus eximius (Stover) to the entry of Marthasterites furcatus Deflandre. Definition lower boundary: Verbeek (1976b). Definition upper boundary: Cepek and Hay (1969a, b). Remarks: At the base of this zone we observed the first specimens of Eiffellithus eximius which is a species defined by having the "shorter" bar making an angle of less than twenty degrees with the longer axis of the basal disc. (see Chapter VI). Near the middle of the zone this angle is generally further reduced to a value between ten and twenty degrees. Such specimens were also figured by Stover (1966, pi. 2, fig ; pi. 8, fig. 15) and Bukry (1969, pi. 28, fig ; pi. 29, fig. 1) and the specimens show for the first time the distinctly forked bars (see chapter on evolution). Other species which have their entry in the Eiffellithus eximius Zone are Kamptnerius tabu latus, Lucianorhabdus maleformis, Lucianorhabdus scotus and Marthasterites inconspicuus.

37 The Eiffellithus eximius Zone as defined here is not identical with the zone with the same name proposed by Roth (1973) for an interval in the Lower and Middle Campanian. Our Eiffellithus eximius Zone coincides with the middle and upper parts of the Tetralithus pyramidus Zone of Cepek and Hay (1960a, b), with the Micula staurophora Zone of Manivit (1971), with the Micula decussata Zone of Roth (1973), with the Kamp tnerius magnificus Zone of Thierstein (1974), with the combined Eiffellithus eximius and Arkhangelskiella specillata Zones of Verbeek (1976b) and with the Eiffellithus eximius s.l. Zone of Manivit et al. (1977). The Lucianorhabdus maleformis Zone of Sissingh (1977) is completely within our zone because its lower limit could be recognized just above the entry of Eiffellithus eximius and it also has the entry of Marthasterites furcatus to define the upper boundary. The base of our zone is in the Praeglobotruncana helvetica Zone and the top in the Globotruncana sigali Zone. The zone has been recorded in the top part of the section of Javernant (Paris Basin) and in the Kef section. Marthasterites furcatus Zone Verbeek 1976 Definition: Interval zone from the entry of Marthasterites furcatus Deflandre to that of Broinsonia lacunosa Forchheimer. Definition lower boundary: Cepek and Hay (1969a, b). Definition upper boundary: Verbeek (1976b). Remarks: The entry of Marthasterites furcatus is a well-known worldwide event, recognized in every Upper Cretaceous biozonation based on calcareous nannofossils. In the Kef section Prolatipatella multicarinata, Broinsonia furtiva and Micula decussata have their first occurrence in this zone. The entry of Broinsonia furtiva in the Marthasterites furcatus Zone is reported by Thierstein (1974) from the Indian Ocean. The level of appearance of Micula decussata is hard to ascertain from the literature, because this species has been confused with Quadrumgartneri (Manivit et al., 1977). v Little unanimity exists about the upper boundary of the zone. Cepek and Hay (1969a, b) propose to use the first occurrence of Arkhangelskiella e thmop ora, a species which is considered here to be a synonym of Arkhangelskiella specillata, and this would move the upper boundary well up into the Upper Santonian. A more detailed subdivision of this long interval is

38 possible, however, and therefore the proposal of Cepek and Hay (1969a, b) is not followed. Manivit (1971) defined the upper boundary of her Marthasterites furcatus Zone by the entry of Kamptnerius magnificus, but the appearance level of this species seems to be heterochronous. In the section of El Kef it was recorded well below the entry of Marthasterites furcatus and therefore it cannot be used at low latitudes. Roth (1973) defined a Marthasterites furcatus total range zone, but such a zone would cover a stil1longer interval than the zone proposed by Cepek and Hay (1969a, b). Thierstein (1976) proposed the entry of Calculites obscurus to be used for the upper boundary, but again this entry was recorded before the entry of Marthasterites furcatus in our material. Sissingh (1977) used the entry of Micula decussata for the upper limit, but as long as there is so much confusion about this widely distributed species it is hard to use it as a marker. Thierstein (1974) did not define an upper boundary. However, he figures and reports Broinsonia lacunosa (as Broinsonia furtiva) and records its range from sediments younger than those from which he recorded the first Marthasterites furcatus. Thus the Marthasterites furcatus Zone as defined here, seems to be recognizable in the section of El Kef as well as in DSDP Leg 26, site 258a in the Indian Ocean near Australia. The zone can be correlated with the upper part of the Globotruncana sigali Zone and the entire Globotruncana primitiva Zone. Age: Coniacian. Broinsonia lacunosa Zone Verbeek 1976 Definition: Interval zone from the entry of Broinsonia to the entry of Micula concava Stradner. Definition lower boundary: Verbeek (1976b). Definition upper boundary: Verbeek (1976b). lacunosa Forchheimer Remarks: At the lower boundary of this zone Broinsonia lacunosa and Quadrum quadratum enter the column. Micula deeussata becomes more abundant, and Broinsonia enormis and Podorhabdus coronadventis become rare. The top of the zone is based on the first occurrence of Micula concava, which species is distinguished from Micula decussata by distinct protuberances at the corners of the cube. After reexamination of samples 34 and 35 of the Kef section it became clear that very rare speciments of Micula concava are present already in these samples. For this reason the upper boundary of the Broinsonia lacunosa Zone is now moved downward to a position

39 between the samples 33 and 34 instead of between 35 and 36 as done earlier (Verbeek, 1976b). Separated taxonomically from Broinsonia parca by Forchheimer (1972), Broinsonia lacunosa is regarded to be the ancestor of the latter species: the presence of Broinsonia parca in Coniacian and Santonian sediments reported by earlier authors has to be re-investigated. The earliest specimens of Broinsonia lacunosa show about seven perforations in each quadrant of the central structure, but specimens from the top part of the zone generally have five. The Broinsonia lacunosa Zone can be correlated with the Globotruncana concavata Zone and the lower part of the Globotruncana carinata Zone. The zone is recognized in the section of EI Kef. The entry of Broinsonia lacunosa has also been recorded from the Indian Ocean (as Broinsonia furtiva sensu Thierstein,1974). Age: Early Santonian. Micula concava Zone Verbeek (this paper) Definition: Interval zone from the appearance of Micula concava Stradner to the entry of Rucinolithus hayii Stover. Definition lower boundary: Verbeek (197 6b). Definition upper boundary: Verbeek (this paper). Remarks: The lower boundary of this zone is based on the evolution of Micula concava from Micula decussata. Lithastrinus grilli becomes rare in this zone. There are but few reports of Micula concava in the literature, because it was commonly considered to be a synonym of Micula decussata. As a consequence the Micula concava Zone is hard to compare with the zonations of earlier authors. The zone can be correlated with the lower part of the Globotruncana carinata Zone. It is recognized only in the section of EI Kef. Age: Early to Middle Santonian. Rucinolithus hayii Zone Verbeek (this paper) Definition: Interval zone from the entry of Rucinolithus hayii Stover to the entry of Zygodiscus spiralis Bramlette and Martini. Definition lower boundary: Verbeek (this paper). Definition upper boundary: Verbeek (1976b).

40 Remarks: In addition to the zonal marker six other species have their first occurrence in this zone. In the lowt::r part Lucianorhabdus arcuatus, Quadrum nitidum and Vekshinella bochotnicae enter the column. Reinhardtites miniporis, Lucianorhabdus quadrifidus and Rhagodiscus reniformis start their range higher up in the zone. Manivit (1971) and Roth (1973) reported Rucinolithus hayii from Santonian sediments of France and the Pacific Ocean respectively. It seems likely that the lower boundary of the zone may be recognized in these areas as well. The zone is documented in the Kef section. It may be correlated with the upper part of the Globotruncana carinata Zone. Age: Middle to Late Santonian. Zygodiscus spiralis Zone Verbeek 1976 Definition: Interval zone from the entry of Zygodiscus spiralis Bramlette and Martini to the appearance of Broinsonia parca (Stradner). Definition lower boundary: Verbeek (1976b). Definition upper boundary: Verbeek (1976b). Remarks: Cribrosphaerella circula and Lucianorhabdus cayeuxii have their entries in this zone. Micula concava becomes more frequent and Lithastrinus floralis disappears. The width of the central area of Broinsonia lacunosa decreases; the width of its margin increases. At the top of the zone the margin is almost as wide as the central area. When the width of the margin is equal to that of the central structure one passes in the evolutionary lineage the arbitrarily chosen morphological boundary between Broinsonia lacunosa and Broinsonia parca. The zone is recognized in the Santonian type locality near Saintes (France), in the section of EI Burrueco and in the Kef section. It can also be recognized in the Pacific Ocean (Roth, 1973, DSDP site 171). The zone can be correlated with the upper part of the Globotruncana carinata Zone, the entire Globotruncana elevata/carinata Zone aiid the lower part of the Globotruncana elevata Zone. Age: Late Santonian; possibly also Middle Santonian (Roth, 1973). Broinsonia parca Zone Verbeek 1976 Definition: Interval zone from the appearance of Broinsonia parca (Strad-

41 ner) to the entry of Ceratolithoides aculeus (Stradner). Definition lower boundary: Verbeek (1976b). Definition upper boundary: Cepek and Hay (1969a, b). Remarks: The lower boundary of this zone is marked by the appearance of Broinsonia parca. Higher up in the zone specimens are found in which the margin is broader than the central area. Kamptnerius magnificus, Cyclagelosphaera rotaclypeata, Reinhardtites anthophorus and Arhangelskiella specillata appear in this zone. Podorhabdus coronadventis, Lithastrinus grilli, Marthasterites furcatus and Lucianorhabdus compactus terminate their range in the Broinsonia parca Zone. The Broinsonia parca Zone as defined here, is probably recognizable in the zonations of Cepek and Hay (1969a, b) and Manivit (1971). In both publications Broinsonia parca is recorded below the entry level of Ceratolitho ides aculeus. The zone is the same as the one defined by Verbeek (197 6b) and Thierstein (1976). Sissingh (1977) recognized both datum levels used here, but he divides the zone into two parts based on the extinction of Marthasterites furcatus; he gives the interval a somewhat younger age assignment. The definition of Roth (1973) for his Broinsonia parca Zone, as the interval between the last occurrence of Eiffellithus eximius and the first occurrence of Quadrum trifidum is not in agreement with the vertical distribution of these species in our material. Eiffellithus eximius was found to disappear later than the entry of Quadrum trifidum. The lower and upper limits of the zone are both within the Globotruncana elevata Zone of the zonation based on planktonic foraminifera. The zone was only recorded in the section of El Kef. Age: Early part of the Early Campanian. Ceratolithoides aculeus Zone Verbeek (this paper) Definition: Interval zone from the entry of Ceratolithoides aculeus (Stradner) to the entry of Quadrum gothicum (Deflandre). Definition lower boundary: Cepek and Hay (1969a, b). Definition upper boundary: Stradner (1963). Remarks: The flora of the Ceratolithoides aculeus Zone is almost the same as that of the underlying zone. It differs only in the presence of Ceratolitho ides aculeus, of which the oldest forms are rather complicated (see chapter on evolution) and the disappearance of Corollithion signum, but this species has been reported from younger strata by Manivit (1971) and

42 Risatti (1973). The central structure of Broinsonia parca is usually rather narrow. In the Kef section the relative number of specimens belonging to the genus Lucianorhabdus starts to increase. In the section of El Burrueco Marthasterites furcatus is present in the Ceratolithoides aculeus Zone, but this is probably due to reworking. The base of this zone is distinguished by Cepek and Hay (1969a, b) and Manivit (1971). The upper boundaries of these authors differ from the one used here. Cepek and Hay (1969a, b) define the upper limit at the first occurrence of Chiastozygus initialis, which species was not found in our material. Manivit (1971) selected the entry level of Lithraphidites quadratus for the upper boundary, but this datum plane can be used much higher in the column. Below this level a further subdivision is possible as shown by Martini (1976) and Sissingh (1977). Parts of the Ceratolithoides aculeus Zone have been observed in the sections of El Burrueco and of Aubeterre, the type locality of the Campanian Stage. The complete zone is found in the section of El Kef. The lower and upper limits of the zone are within the Globotruncana elevata Zone. Age: Later part of the Early Campanian and early part of the Middle Campaman. Quadrum gothicum Zone Martini 1976 Definition: Interval zone from the entry of Quadrum gothicum (Deflandre) to the appearance of Quadrum trifidum (Martini). Definition lower boundary: Stradner (1963). Definition upper boundary: Roth (1973). Remarks: In the section of El Burrueco Cribrocorona gallic a is the only species to make its appearance in this zone; in the Campanian type section at Aubeterre it is Arkhangelskiella cymbiformis. Both species enter the coluren in El Kef in the next higher Quadrum trifidum Zone. Microrhabdulus belgicus and Lucianorhabdus quadrifidus have their last occurrences. In accordance with Martini (1976) and Sissingh (1977) the Quadrum trifidum Zone is separated from the earlier proposed Quadrum gothicum Zone of Verbeek (197 6b). In the section of El Burrueco, the restricted Quadrum gothicum Zone can be recognized in five meters of sediment and in Aubeterre in about 35 meters. In the sampled section from El Kef used by the present author (197 6b and this paper), the zone seems to be not represented, but in additional material from the area of El Kef it could be recognized.

43 Also Sissingh (1977) reports the zone from EI Kef. It must be situated between our samples AFN 183 and AFN 184 and therefore it must be hidden in the unexposed SO meters in between. The upper and lower boundaries can be correlated with levels in the Globotruncana elevata Zone. The zone was recognized in the sections of EI Burrueco (Spain), Aubeterre (France) and in material from Tunisia, taken outside the main sections. Age: Later part of the Middle Campanian. Quadrum trifidum Zone Verbeek (this paper) Definition: Interval zone from the entry of Quadrum trifidum (Martini) to the entry of Lithraphidites quadratus Bramlette and Martini. Definition lower boundary: Roth (1973). Definition upper boundary: Cepek and Hay (1969a, b). Remarks: Several species disappear in this zone: Reinhardtites miniporus, Lucianorhabdus scotus, Broinsonia enormis, Eiffellithus eximius, Rucinolithus hayii and Reinhardtites brooksii. In the upper part of the zone the number of elements composing Ceratolithoides aculeus (Stradner) becomes reduced from twelve to eight (see chapter on evolution). Roth (1973) and Martini (1976) conceive the present zone as a total range zone of Quadrum trifidum. They even recorded a gap between the exit level of Quadrum trifidum and the appearance level of Lithraphidites quadratus in the Pacific Ocean. Also Hekel (1973) reports such a gap from the Pacific Ocean. Perch-Nielsen (1972) did not find Quadrum trifidum and Lithraphidites quadratus together in the North Atlantic either. For the hiatus interval Martini (1976) used the Arkhangelskiella cymbiformis Zone of Perch-Nielsen (1972). The specimens earlier assigned to Quadrum gothicum and Quadrum trifidum by Verbeek (197 6b) from the Lithraphidites quadratus Zone are very rare. They are so badly preserved that after reexamination the present author prefers to list them as "Indeterminable". As a consequence it may be concluded that Quadrum gothicum and Quadrum trifidum cannot be proved to be present in the Lithraphidites quadratus Zone in the Kef section, and our zones comes closer to the definitions by Roth (1973) and Martini (1976). Even the gap reported by Roth (1973), Martini (1976) and Thierstein (1976) may be present in EI Kef, though no sample was available from the Campanian-Maastrichtian boundary interval, where Quadrum trifidum and Lithraphidites quadratus both are absent. However, Sissingh (1977) did report such an interval, but in our investiga-

44 tion Lithraphidites quadratus was found well below the entry level of Abathomphalus mayaroensis (Bolli), whereas Sissingh (1977) reported the reverse. For this reason it remains unclear whether the "Arkhangelskiella cymbiformis Zone" can be recognized in the section of EI Kef. The Quadrum trifidum Zone was recorded in the sections of EI Kef, EI Burrueco and Aubeterre. It can be correlated with the interval from the top of the Globotruncana elevata Zone to the top of the Globotruncana contusa Zone. Lithraphidites quadratus Zone Bukry and Bramlette 1970 Definition: Interval Zone from the entry of Lithraphidites quadratus Bramlette and Martini to the entry of Micula murus (Martini). Definition lower boundary: Cepek and Hay (1969a, b). Definition upper boundary: Bukry and Bramlette (1970). Remarks: Although Lithraphidites quadratus may be rare in certain sections, it is a generally accepted marker for the Maastrichtian. Thoracosphaera operculata has its entry in the Kef section at the base of this zone; Ceratolitho ides arcuatus, Markalius inversus, Lithastrinus? stradneri and Discolithina spiralis have their entry higher up in the zone. The latter two species are rare and c. arcuatus has been reported from the older sediments of the Quadrum gothicum Zone of EI Kef by Sissingh (1977). Lucianorhabdus arcuatus and Broinsonia parca disappear from the column, Micula decussata and Arkhangelskiella cymbiformis become abundant. Micula concava shows very long processes on the corners. The diagnosis of the lower boundary is identical with those of Cepek and Hay (1969a, b) and Manivit (1971). The upper limit is the same as the one chosen by Bukry and Bramlette (1970) and Roth (1973). Cepek and Hay (1969a, b) and Manivit (1971) defined the upper boundary at the entry of Nephrolithus frequens. This species was not found in the section of EI Kef. It is thought to have about the same level of appearance as Micula murus, but it is restricted to higher latitudes (Worsley and Martini, 1970). The Lithraphidites quadratus Zone is recognized in the section of EI Kef and in the Mb unit of the ENeI quarry, which is the type locality of the Maastrichtian. The zone may be correlated with the Globotruncana contusa Zone, the upper limit of which was placed between the same samples as the upper limit of the Lithraphidites quadratus Zone.

45 Age: Early and Middle Maastrichtian, but for the earlier part of the Early Maastrichtian. Definition: Interval zone from the entry of Micula murus (Martini) to the extinction level of most Cretaceous nannofossils. Definition lower boundary: Bukry and Bramlette (1970). Definition upper boundary: Cepek and Hay (1969a, b). Remarks: Because in this paper a different species concept of Micula murus was followed than in the earlier publication (197 6b), the lower limit of the zone in El Kef is situated in younger deposits now than it was in The zone proposed now also contains the Nephrolithus frequens Zone of Verbeek (197 6b), because the author started to doubt his earlier determinations of the coccoliths assigned to Nephrolithus frequens. Our sample AFN 200 was kindly restudied by Perch-Nielsen, who concluded that Nephrolithus frequens is absent. Sissingh (1977) reports this species from El Kef in his own material. Micula murus is restricted to tropical and subtropical areas, whereas Nephrolithus frequens seems to be present only in more boreal areas. Both species either have more or less the same range (Worsley and Martini, 1970), or Nephrolithus frequens appears before Micula murus (Thierstein, 1976). The upper part of the zone is characterized by the presence of Ceratolithoides kamptneri and Eiffellithus parallelus. Zygodiscus minimus, Lucianorhabdus maleformis and Quadrum quadratum have their last occurrence below the top of the Micula murus Zone. The other species, which become extinct in this zone in El Kef, have been reported from uppermost Maastrichtian sediments elsewhere. Thoracosphaera operculata becomes more frequent near the top of the zone. The upper boundary of the zone is often rather vague, because considerable reworking of Cretaceous nannofossils is generally observed in the lowermost Tertiary sediments. This makes it often impossible to determine the extinction levels accurately or to recognize the NP 1 Zone of Martini (1971). The Micula murus Zone can be correlated with the Racemiguembelina Zone and the Abathomphalus mayaroensis Zone. It was recognized in the section of El Kef and the upper part of the type Maastrichtian. Age: Late Maastrichtian.

46 , As stated under the remarks of the Micula murus Zone its upper limit could not be recognized distinctly. Sample of EI Kef contains only Cretaceous calcareous nannoplankton, but an Early Danian planktonic foraminiferal fauna. It is assigned without positive evidence to the NP 1 Zone. Sample AFN contains Cruciplacolithus tenuis (Stradner), without Chiasmolithus danicus (Brotzen) and is placed in the NP 2 Zone.

47 CORRELATION WITH THE STRATOTYPES OF THE MIDDLE AND UPPER CRETACEOUS STAGES IN EUROPE INTRODUCTION Between 1840 and 1860 Coquand, d'orbigny and Dumont introduced the European stagenames for the Middle and Upper Cretaceous. Most of these stages are generally accepted and widely used. Only Dumont formally selected a stratotype for his Maastrichtian. Later authors designated the stratotypes for the Albian through Campanian. Not all stratotypes contain stratigraphically useful macrofossils. The Cenomanian stratotype contains ammonites, the Turonian stratotype Inoceramids and the Coniacian and Campanian stratotypes Ostrea and some other groups. No single group of macrofossils is present in all stratotypes. Second order correlations are required to correlate the macrofossil biozonations with the stratotypes, resulting in a rather chaotic situation (Van Hinte, 1968; Barr, 1972; Seronie-Vivien, 1972; Marks, 1972). The French colloquia on the Lower Cretaceous in 1963 and on the Upper Cretaceous in 1959 established a scheme for the correlation between the macrofossil biozonation and the stages, however, the stratotypes do not contain the macrofossils used for the zonation. With the exception of the Coniacian stratotype, they do contain foraminifera and calcareous nannofossils, of which the calcareous nannofossils, though sometimes poorly preserved, allow a first order correlation to be established. From these stratotypes Manivit (1967, 1971) and Sissingh (1977) studied the nannoflora, but no detailed descriptions of the floras were given. Porthault (1974) correlated his zonation based on planktonic foraminifera with the ammonite zonation established by Thomel (1969) in SE France, which is partly different from the one of the colloquia, but which resulted in the first attempt to make such a second order correlation. Verbeek (197 6a) described the nannoflora of the Cenomanian stratotype. Marks (1977) gave a paper on the Cenomanian-Turonian boundary problem and proposed the entry of Praeglobotruncana helvetica to furnish the datum level to recognize the Turonian base. Verbeek and Wonders (1977) correlated their calcareous nannoplankton and planktonic foraminifera zonations to the Turonian stratotype. Recently Van Hinte (1976) compiled all available data in his Cretaceous Time Scale.

48 In this paper all stratotypes are restudied, except those of the Cenomanian and Turonian, to establish a first order correlation to the proposed zonation (fig. 1). It is shown that the stratotypes cover very short time intervals. In the long interval between the Turonian and Santonian stratotypes insufficient chronostratigraphic data are available. According to Larcher et al. (1965), who gave a historical review of the Albian Stage, the name was introduced by d'orbigny in 1842 to replace the :;:: < () i~i(i?i~ 1/:1' ~~~ ~~~!.=~i;i~.. I~I~i~!~!~I~ 0... I'J:W1.b (]I;,!:>, U1!(O o!----'i~ x x x x x >< x x x >< x X Watznaueria barnesae X X X X X X X X X X X X Wat:znaueria communis cvclagelo-sphaera margar~ji Yekshine/la crux. Parhabdo/it:hvs embergeri Sf;@phano/ithion laffittei i.1 Braarudo.sphaera bige/owl ~BidiscuS rot:atorius' + i +:' + " + Manlvite/la pen1l"natoidea I. I Wal:z;nEuer;a biporca + +:.,I'i+ +1' Rl7agodiscus Esper ',. 'I :. I, ';! Z/fgodisctls elegans +1' I' i -I- +-:' +1_ Lif:hraph'-dif:es c:,arnio/ensis 1-:. Ii' I Cretarhabdus conieus + +,.! i' i. ',' Cretarhabdus sur/rei/us '! cruciellipsis chiasta i Cruc/eJlipsis cupil/ieri i. Markalius circumradiacus I : Cretarhabdu$ crenul.atus I..:.,! -! i. Rhagodiscus sp/endens X ' :+1+ +,+I+I-I+i+:+ Zvgoa/scwsdiplogr.ammus i Parhabdolithu5 inf'initus I. i.' +!. - I_i _:. Tegumentum srradneri I _ i _ I. Chiascozlfgws /itt:erarius I..'. _ Podorhabdus decorus +.,. i. -i + Vek..shinell.a angusfa io 0 Rhagodiscusangusfws _! _: I _ Coro/lithion achylo.sul7l - + +!+i-.:-:+ - t..ithastrinwsflt7ra/is -- I '.! I! I Halfes-iies.a/biensis : : : t.". : I _ :!:': :::::::r:::;:,:ecuss.atus aidiscus ignot:w.s i - Podorhabdws coronadyentis _I ;.. Prediscosphaera columnata - - _ :. _ Cretarh.9bdw$ /oriei..1 i - _ coroj/it:hion.signuf77 scapholithus sp. _ 6aarderella granu/ifera ::: N C;; to ~ «) ~ 0 ~ to.::::j ~ %lndeterminable

49 SECTIONS S TAG ES AMMONITE NANNOPLANKTON ZONATIO N ZONATION Courcelles term Gault. They proposed some exposures in the area of the Aube to form the composite Albian stratotype, from which they described in detail the macrofauna and lithology. On the basis of the macrofauna zonation they divided the stage into a Lower, Middle and Upper Albian. Jannin (1965) studied the microfauna of the sections that together comprise the Albian stratotype. The planktonic foraminiferal species she observed is Hedbergella planispira, a species with restricted biostratigraphic importance. A study of the calcareous nannofossils from the Albian stratotype was carried out by Manivit (1971). The section of Villemoyenne she assigned to her Hayesites albiensis Zone, and that of Courcelles she placed into her corollithion rhombicum Zone. Thierstein (1973) made a second order correlation on sections in SE France, previously searched by Moullade (1966) for planktonic foraminifera. According to these authors the Albian- Cenomanian boundary may be placed in the Eiffellithus turriseiffeli Zone, a proposal followed in the present paper. Samples were available from the sections of Montieramy, Villemoyenne and Courcelles which belong to the composite Albian stratotype. The distribution of the calcareous nannoflora is given in fig. 10. The preservation of the flora in most samples is excellent, because the fossils show very little overgrowth with secondary calcite, but dissolution occurs in some of the samples. Larcher et al. (1965) correlated the Lower Albian, represented by the sections of Montieramy and Villemoyenne, with the Douvilleiceras mammila- Hoplites Q!Z -«dentatus '0- 'OlD.-..J 2«Lye IIi ceras {yell i Villemoyenne Montieromy LZ Q!«~- old..j..j «Douvi/leceras mamillatum Prediscosphaera co{umnata

50 tum Zone. According to their figure 2 the sediments of Villemoyenne are younger than those of Montieramy. Courcelles represents the Middle Albian, assigned to the Hoplites dentatus Zone and the Lyelliceras lyelli Zone (Larcher et ai., 1965). In all three sections associations of the Prediscosphaera columnata Zone have been recorded (fig. 11). This zone is also recognized in the lowermost part of the section of El Burrueco, but these sediments are probably younger, because the specimens of Prediscosphaera columnata found in the Aube region are much smaller than those of El Burrueco. Moreover, some species with known entries in the Prediscosphaera columnata Zone, have been recognized in the Burrueco section but they are absent in the Aube region. In 1848 d'orbigny defined the Cenomanian Stage as the rocks, on which the town Le Mans has been built, but he did not designate a type section (Marks, 1967a; Kennedy, 1970; Kennedy and Juignet, 1973; Juignet et ai., 1973). Marks (1967a) proposed a composite section in the area of St. ulphace-theligny-moulin de l'aunay as the stratotype for the Cenomanian Stage. This author (1967a, b; 1968) described the foraminifera from two major outcrops in this area, the Craie de The1igny (samples Fr 1162-Fr 1164) and the Couches a Orbitolina complanata near BaIlon (samples Fr 1171-Fr 1173). The Couches a Orbitolina complanata had been correlated on the basis of ammonites (Mantelliceras mantelli Zone) with the Lower Cenomanian by earlier workers (Marks, 1967a, b; 1968) and consist of a friable sandstone containing a microfauna of benthonic foraminifera with Orbitolina. The marls of the Craie de Theligny are correlated with the Acanthoceras rothomagense Zone (Marks, 1967a, b; 1968). Verbeek (1976a) described the calcareous nannoflora of both exposures, using samples of Marks (1967a, b; 1968) with the addition of sample Fr 1498 from the Theligny exposure. The three samples from the Couches a Orbitolina complanata show a flora in which overgrowth with secondary calcite is common. The samples Fr 1162-Fr 1164 and Fr 1498 from the Craie de Theligny contain a nannoflora, which is rich and well preserved in Fr 1162 and Fr Both sections were originally assigned to the Lithraphidites alatus Zone of Roth (1973). However, because the samples Fr 1662 and Fr 1493 contain Lithraphidites acutum they are now assigned to the Lithraphidites acutum Zone and the others to the Eiffellithus turriseiffeli Zone (fig. 12). Only the top of the Theligny section contains plank-

51 tonic foraminifera and can be assigned to the Rotalipora cushmani Zone (Marks, 1967a, b). Marks (1977) discussed the problem of the Cenomanian-Turonian boundary and proposed to correlate the first occurrence of Praeglobotruncana helvetica with the upper boundary of the Cenomanian Stage. This proposal is followed in the present paper. The entry of Praeglobotruncana helvetica has been placed in the upper part of the Quadrum gartneri Zone by Wonders and Verbeek (1977). As a consequence the top part of the Eiffellithus turriseiffeli Zone, the Lithraphidites acutum zone, the Gartnerago obliquum Zone and the lower part of the Quadrum gartneri Zone are considered to correspond with the Cenomanian Stage. SEC- IMPORTANT NANNOPLANKTON FORAMINIFERAL AMMONITE SAMPLES TIONS SPECIES ZONES ZONES ZONES 1498 ; E ;:,+ >, ::: c: 1163 c + +~"'.2+ ~ <::<:: 01 u.., ct~ u 0-.- ~- <:: 0.c 2: - ~ I _+ +:.:; 2 ~~ 0._ U '" Lithraphidites Rotafipora ~ ~~ ~ acutum cushmani Eiffellithus ~.- ~ turriseiffel i ~~ 1164 t~+ ~ 0 - ~ ~~ ~ :5:+]+ :::Q. - 0 ~+~ Acanthoceras rotomagense c '-., 0 ~3 Eiffellithus Mantelliceras = turriseiffeli mantell i 0 0..J I1l Fig. 12 The calcareous nannofossil biostratigraphy in the Cenomanian stratotype correlated with the planktonic foraminiferal and ammonite zonations. In 1842 d'orbigny defined the Turonian as follows: "Je propose de designer a l'avenir l'etage, qui m'occupe (craie chloritee, glauconie crayeuse, craie tuffeau et gres verts) sous Ie nom Turonien, de la ville Tours (Turones)

52 ou de la Touraine (Turonia), situees sur ces terrains". In 1847 d'orbigny recognized two different faunas in this Turonian and its lower part was separated as the Cenomanian (Somay, 1956). A stratotype was not proposed by the original author and therefore Lecointre (1959) designated one: "Je fais debuter cette coupe a la carriere du Fretevou (improprement appelee Forteveau par Ebray, puis de Grossouvre) commune de Chatillon-sur-Cher". Lecointre (1959) and Butt (1966) described the lithology of the quarry near Fretevou. Butt (1966) and Bellier (1971) described the poorly preserved foraminiferal content of the section; Verbeek and Wonders (1977), the equally poor calcareous nannoflora. Marks (1977) proposed to correlate the entry of Praeglobotruncana helvetica with the base of the Turonian, because this entry is the first distinct planktonic foraminiferal event, younger than the Aetinocamax plenus Zone, which ammonite zone is placed in the uppermost Cenomanian. The entry of Praeglobotruncana helvetica was correlated by Verbeek and Wonders (1977) with the Quadrum gartneri Zone of the calcareous nannoplankton zonation. The lower limit of the Quadrum gartneri Zone is recognized in the middle part of the section of Fretevou. Praeglobotruncana helvetica, however, was not recorded from the section (Butt, 1969; Bellier, 1972; Hart, 1976). As a consequence the lower limit of the Turonian Stage must be present somewhere in the Fretevou section, but it is impossible to recognize the exact position of this boundary in the quarry. In 1959 at the Colloque sur Ie Cretace Superieur frans;ais the upper boundary of the Turonian Stage could not be clearly correlated to any zonation (Dalbiez, 1959), and little progress has been made since that date. Seronie-Vivien (1972) suggests that there is a hiatus in the sedimentary sequence of the Turonian and Coniacian in France. No first order correlation between the planktonic foraminiferal zonation and the stratotype section seems to be possible (Van Hinte, 1976). In the present paper it is shown that a sample taken from Coquand's sables et gres de Richemont in sequence overlying the Coniacian stratotype section at J avresac near Cognac, contains a nannoflora indicating the Marthasterites furcatus Zone. On this tenuous evidence the boundary between the Turonian and Coniacian Stages is provisionally drawn at the base of that zone, which is close to the Globotruncana primitiva datum in the planktonic foraminiferal biostratigraphy (see also remarks on the Coniacian). Without positive evidence the larger part of the Turonian is correlated with our Eiffellithus eximius Zone.

53 CONIACIAN In 1856 Coquand subdivided the Upper Chalk of the Saintonge (Charente maritime) in three "etages", of which the lowest was subdivided into three "sous-etages". In the next year Coquand raised the lower two of his "sousetages" together to the rank of a stage: the Coniacian, characterized by the presence of Ostrea auricularis Brongniart. The stratotype is considered to be the section described by Coquand in 1858 as: "les escarpements, que l'on trouve immediatement en sortant de Cognac, au-dessous de la grande allee du pare, dont Ie prom est indique par la figure 74". The park mentioned is the one of Franc;:ois-Ier(Seronie-Vivien, 1959, 1972; Van Hinte, 1965). This stratotype contains neither foraminifera nor calcareous nannoplankton and it cannot be correlated directly with the calcareous nannoplankton zonation. From an exposure with Ostrea auricularis in the Sables et gres de Richemont along the road N 141 near Javresac at about one kilometer from the type section a sample was taken (Fr 1519). This sample contains transitional forms between Quadrum gartneri and primitive forms of Micula decussata (Sissingh, in prep.). Therefore sample Fr 1519 is assigned to the middle part of the Marthasterites furcatus Zone as defined in the present paper. The section from which sample Fr 1519 was taken directly overlies strata to be correlated with the Coniacian stratotype. This allows a second order correlation between the lower part of the Marthasterites furcatus Zone and the Coniacian stratotype. The upper boundary of the Coniacian Stage is generally correlated with the entry of the ammonite Texanites texanum. During the excursions of the MCE congress (Nice, 1976) a sample was taken in a section near La Penne (SE France) from sediments assigned to the Texanites texanum Zone (sample Fr 1782). This sample contains a nannoflora, which may be assigned to the Broinsonia lacunosa Zone. Therefore the boundary between the Coniacian and Santonian is correlated with the lower limit of the Broinsonia lacunosa Zone. In the section of EI Kef (Tunisia) this entry is found in the same sampling interval as the entry of Globotruncana concavata. Because the lower limit of the Coniacian Stage was correlated with the lower boundary of the Marthasterites furcatus Zone and the upper boundary of the stage with the lower limit of the Broinsonia lacunasa Zone, the entire Coniacian can be correlated with the Marthasterites furcatus Zone as defined in this paper.

54 SANTONIAN As mentioned in the remarks on the Coniacian, Coquand subdivided his lowest "etage of the Upper Chalk into three "sous-etages". The uppermost of these three "sous-etages" was raised to the rank of stage by Coquand in 1857: the Santonian. The sediments assigned to the Santonian by Coquand are soft limestones with silex nodules, with Ostrea auricularis below the base and with Ostrea vesicularis above the top. In 1858 Coquand designated the exposure along the road from Javresac to Saintes (Charente, France) as the stratotype (Van Hinte, 1965). Seronie- Vivien (1959, 1972) considers the section near the railway bridge across the Charente near Saintes as the stratotype. From this section four samples (Fr ) have been studied (fig. 13). Van Hinte (1965) regards an exposure at a rubbish-dump along the road N 141 at about four kilometers from Cognac to be the stratotype. One sample (Fr 900) of this exposure has been studied. The nannofloras of both sections are rich, but poorly preserved, because of the strong overgrowth with secondary calcite. Zygodiscus spiralis is present and Broinsonia parca absent. Therefore the sediments of both sections are assigned to the Zygodiscus spiralis Zone. Little agreement exists about the correlation of the planktonic foraminiferal zonations and the position of the Santonian-Campanian boundary (Van Hinte, 1976). The correlation with the entry of Globotruncana elevata is uncertain, because it is shown that both this entry and the nannoflora of the Santonian stratotype can be correlated with the Zygodiscus spiralis Zone. Therefore we propose to correlate this boundary with the first occurrence of Broinsonia parca, in accordance with Manivit (1971), Roth (1973), Bukry (1974) and Thierstein (1976). The Santonian Stage therefore is to be correlated tentatively with the Broinsonia lacunosa Zone, the Micula concava Zone, the Rucinolithus hayii Zone and the Zygodiscus spiralis Zone. The Campanian Stage is the second "etage" recognized by Coquand in 1856 in the Upper Chalk. This second stage is characterized by soft limestones with Ostrea vesicularis Lamarck. In 1853 Coquand made clear that he considered the section of Aubeterre to be the stratotype, which exposure he described in detail and subdivided in the lithological units A through G (Van Hinte,1965).

55 Zygodiscus spirafis RTtfft ~ tf ZONE LITHOLOGY 0,, ",3 '",,. '" 0 ;;j ~ ;;j ;;j SAMPLES 0 '" " 0> + 0 x + 0 Watznaueria b~rne.$ e Watznaueria coj77mvnis C/{claqe/osphaera margareli VeJ(snlne/la crux Steph<fnolithion I.aHit:t#i Braarudosphaera big~/owi ManlyiteJla pemma toit:tea Watznaueria J:>iporta Ztt90diSCus,legans + l.fthraphidites carnio/ensis COniCN$ cr,t-arhabdus X + + Nannoco!7uSrruitri Creiarha/X1u$ Rhagodiscus + Zygodiscvs + chiasrozygus Podorhabclusdlcoru$ R..hagodisc.ws<!Ingvst:vS' Hlsey-tum.1 MarJ(alius Cretarhabdus surirellvs circul71raqi3ius' crenul.;/cus spll!'ndeons diplogrammvs litterarius X 0 +. V Ol II> II> 0,, ". ;f!- a Ol ;;- ;f. ;!- + Cribrosph.aerdlla ehr,n17ergh Tranolithus orionaru$ L./th3sCrinus rloralis Biscutum constans ignot:us Hellcallthus rrabecu/~t:ws Predlscospha~ra spinosa Corollirhion signum Cretharhabdus loriel.1 + Brt'insoJ'Ti; enormls + X Cribrosph;,erella pelta Zygodiscvs minimvs X EIFFellithus turri.seifreli Z'l'90discvs acanthus dtnphlpt'ns AhmluUI.r,J/. r~gv/aris Microrhabd#lu.s bslgicw.s X X PrildiscoSph4Sr.l er~&8cl!ta C/f/indr.;l/ichus piarevs Mlcrorhabdv/u,s decor4t'vs (Sdrtner;go oinlqvvm octor.dl,atu$ obscvrus g,-plap C'Ilinclralichus s6'rratus exin1iu$ t:libulatus L.uclanc>rh3bdus f1?a/~fcrn1js Tlirt/va + Micul3 decussat'4 4(V,if1drVm qv.adr.;~um conc.av. int~rrvptu$ L"cianorh,abdl-fs arcwatus R..inh,art:tl-it~s l71inlporus quadrlfidu.s Zl(god'iS'C'w.sspir;lis % ~ Ind.t~rmin bl Chiastozygus + t:(uaclrumg~r~n,ri Ahmw~ll~re/l. JCeinhardt:it~$brcoksii C3Icullc~$ + + EiHel/lthus l(ampt'n.-rins 13rolnscnia 8rolnsoni41.acl-fnos3 Mlcvla Chiasrozygus Lucilnorh.abdvs ~!li.. "l '" Distribution chart of the calcareous nannoflora in the Santonian stratotype of Seronie- Vivien (1959, 1972) and Van Hinte (1965).

56 The samples used for the present study of the Aubeterre section are those studied by Van Hinte in The samples from the lowest units (G and F) contain a rich and rather well preserved nannoflora The units E, D, C and B contain a poor and badly preserved flora and sample Fr 826 taken from unit A is devoid of calcareous nannofossils (fig. 14). Three zones can be recognized in the section: the Ceratolithoides aculeus Zone, the Quadrum gothicum Zone and the Quadrum trifidum Zone. The boundary between the two lower zones is situated between samples Fr 524 and Fr 820 in the top of unit G. The Quadrum trifidum Zone was recognized only in sample Fr 824 at the top of the section in unit B. Manivit (1971) assigned the lower part of the section to her A rk hange lskiella specillata Zone and the upper part to the Ceratolithoides aculeus Zone, which is based on the entry of Ceratolithoides aculeus. This datum level was not recognized in the present study of the sequence and the species is probably already present in sediments older than those of Aubeterre. Martini (1976) reports the Ceratolithoides aculeus Zone in the lower part and the Quadrum gothicum Zone in the upper part of the Aubeterre section. The Campanian-Maastrichtian boundary is generally correlated with the exit of Globotruncana calcarata, a datum level recognized between the entries of Quadrum trifidum and Lithraphidites quadratus. Therefore the Quadrum trifidum Zone straddles the Campanian-Maastrichtian boundary. The other zones assigned to the Campanian are the Broinsonia parca Zone, the Ceratolithoides aculeus Zone and the Quadrum gothicum Zone. In 1849 Dumont separated the "calcaire de Maastricht" from the "craie senonienne". The section below the Lichtenberg Farm is considered to be the type locality. The lowermost unit of the type Maastrichtian is the Ma (or coprolite) layer. The total type section is divided in four lithological units (Ma-Md) and it is visible near the entrance of the ENCI quarry (Romein, 1962). The calcareous nannoplankton flora is poorly preserved, especially at the top of the Mc and in the Md. The Ma does not contain calcareous nannoplankton. The nannoflora of the Mb is assigned to the Lithraphidites quadratus Zone and the flora of the Mc and Md to the Micula murus Zone (fig. 15). The coincidence of a lithological and a biostratigraphical change in the section may indicate a hiatus in the section. The calcareous nannofossils of the type Maastrichtian have been studied before. Bramlette and Martini (1964) gave a species list, but they do not

57 Ceratolithoides Quadrum f5.f? aculeus 5.1. gothicum ~~8. BIOSTRATIGRAPHY ZONE ZONE 00' 3 I 0 ~ 0> ~ ~ \ 0 I '", '" ~ 3 LITHOLOGY x \ II ~ 0 0> ~~ :{=i=i~~ :;' ~~~~ ~~ (J1(J1(J1Q1Q1 (J1(Jl(J1Q1 ~~ SAMPLES f\)f\)f\)f\) '" '" "'''' '" ~ "'''' "'''' "0 - '" - 0'" "'''' "'" o J:t,. CD r$3 ~. ~ ~... watnaueria Cl(c/age/osphaera V~kshinel/a Stephano//th/on Braarudosphaera Bidiscus... i, Manivite//a pel77macoidea,. '. Lithr3phidites... Cretarhabdus Cretarhabdus Nannoconvs Cretarhabdus, i " Zl(godi$cu$ Chiastoz!o"gU$ Podorhabdus Crlbrosphaerella ehrenbergii Rhagodiscus Tranolithus... 0"'1'"... Biscu/:vm cons tans Bidisevs i I Hel/co/iehus t:r<!1pecu/atus I.' Broinsonia Cribrosphaerella pe/ta Zl(gocliscvs..., +X+XX X 0 Zl/godiscu..s.,.'... Chiastoz/f9ws, Ahmwel/ere/la Microrhabdu/us 00 XOOO+ X I... QuadrU177gcar/:neri..., Ahmuellerella Reinhardtires Clflindr<i9lithus E!fTel/it"hWSeximiws Kamptnerlvs Broinsonla Micwla decussata Micw/a Vel(shinli'l/a... Z/lgodlseus Lucianorhabdu$ cribrosphaert!1ll.a... BrC'insonia Arl(hangelSl(iell<3 CeracC'/ithoides, ~einhardtires V barnesae nlargare/i crux /afrittei bigsiowl rotacoriws carnio/ensis conicvs $wrirellws truitt:i crenv/atus JZhagoaiscussplel'7dens dip/ogrammus litterarius decorvs angvscus arianatus, Lithastrinus rlara/is ignorvs PrtS'discosphaero'!Jspinosa Corollithion $igi7w177 enorrnis Micrarhabdwlws minimus EifT'e/lithus tut"riseiheli acanthus amphipons regularis be/gicws Pr~dist::::o.sphaera cret:acea deccrarus ocf:;oradiata brook..sii sti'rra-tus Calcu/it-es obscwrws graup 6l..uadrum Reinhardtites Rucino/ithus "'''' "''''''' "'''' uo- "''''''' '"" "'''' Arkh3ngBls/(lel/a tabwlat:us Twrtiv3 ConC-l!!IVd halfi! bochoi:nlcae nitidhi11 minlporus spira/is c8 evxii circul4 parea anthophorus specillat:a.4cw/ews s.l.... 6(uadrurn gof:;hlcwl71 cyrnbirormis GluadruffJ tririduffl % Indeterminable 00 Fig. 14 Distribution chart of the calcareous nannoflora in the Campanian stratotype. Lithology after Van Hinte (1965). The floras of the samples Fr 522-Fr 520 are too rare to give frequency indications. "

58 indicate from which level the samples came. From their distribution chart and from the results of the present study it is concluded that the samples probably were taken from unit Mb. Nephrolithus barbarae Gorka, which they report, may be a marker for the uppermost Maastrichtian, but this species was not found during the present study. The results we obtained are in agreement with those of table 2 of Martini (1976). The Maastrichtian-Danian boundary is generally correlated with the exit of most Cretaceous calcareous nannofossil species. As a consequence, the top of the Quadrum trifidum Zone, the Lithraphidites quadratus Zone and the Micula murus Zone have to be assigned to the Maastrichtian Stage. L.qUQ- Micu!a dratus murus ZONES ~I-j x 0 +. :;:: :;:: LITHOLOGY v II () Q. ~J f-- ~ 01 OJ OJ ~ W3 0,, ;; -:- 0 o? -:- 01,,, -: w :::j;:n ;: a. SAMPLES Wacz:naueria barnesae crux Vekshinel/a Parhabdo/ithus Bl77bergeri St:ephanolithion lafficrei Braarwdosphaera bigelow; X ++ + Lit"hr.aphidices carniolensis Cret:ErhaPdus conicus sur/rei/us crenwlat:ws ctip/ogra.mmws Chiast-ozV9uS'lit:terariw$ a'ecorw$ Cr;brosphaii'r~lla ehrenbergli Rh.agodiscU's angust"vs const.,ns Bldisews ignocus H4/ico/ichus CrabeclJ/attls PrediscoSph,;n,.r8 spinosa Coroll/chion signum pelta Scaphotit.hU$ sp X XX+ Eiff~llithJ.ls tyrrisfi1iffe/i.i1h7phipons rl!'!gv/~ris Corollit"hiol7 exiguum X X++ Prediscosph,aarE cr~tecea + Microrh8bdv/vs decoracus + Q,uadrul'T7 garcneri Ahmv,llt!rella occoraetiara Cafculit~sob.scurHs group tabu/a!:uos + + Micwla Qacussat-a 6?vadrum qwadracu'/ti conca va Rhagodiscvs reniformis Lucianorhabdu$ cal.feuxii + Arkhange/sk/tPlla c/{mtnrormis X Lithraphidites qvaetratus + opercul ta Markalius inversw$ + Micvla muru$ '" "'.. '" % Indete rminaoje m", + + Cret:arhabdus CrecarhBbdus ZlfgOd/scvs PodorhabdiJS + 8iscucu177 Cribrosph4er~ll~ Chiastozygvs Ahmv~//ere/l~ Kampcn~r;us Micula + ZygOdiscvs.spir.:Jlis Thor<!Jcosphaer.a '" Distribution chart of the calcareous nannoflora in the Maastrichtian stratotype. The flora of sample NL 15 is too rare to give frequency indications.

59 The most important papers with definitions of terms are those of Braarud et al. (1966), Reinhardt (1966), Hay et al. (1966), Bukry (1969) and that resulting from the "Round Table Conference" of the "Second Planktonic Conference" (Farinacci, 1971). Braarud et al. (1966) merely defined the different types of nannofossils. Hay et al. (1966) compiled all terms published at that moment both for types of nannofossils and for their components. The other authors gave definitions of various components. The present paper follows especially the glossary compiled by the "Round Tabel Conference", although its terminology does not include all features observed. Some additional terms are defined in this chapter. Most Cretaceous calcareous nannofossils are composed of one or more cycles of elements surrounding a central area, in which all kinds of structures may be present. These cycles together have been named "margin" by Hay et al. (1966) and "rim" by Bukry (1969). In the present paper the term margin of Hay et al. (1966) is preferred, because the term rim has been used also for separate cycles of the margin. The margin In different families the margin has been constructed in different ways (fig. 16). If the margin consists primarily of two cycles, of which the distal one is much higher and the other attached to the proximal side of the distal one, then the terms distal and proximal margin cycles are used (Eiffellithaceae, Stephanolithionaceae). Often a generally high, but rather thin cycle forms the border between the margin and the central are. This cycle, which is a part of the margin, is the inner margin cycle (Podorhabdaceae, Eiffellithaceae, Coccolithaceae). Very rarely a high and thin cycle at the outer side of the margin is present and is called the outer margin cycle (Eiffellithaceae). Another construction type of the margin consists of several thin and broad cycles. If two cycles are attached only to an inner margin cycle then they are called shields (Podorhabdaceae, Coccolithaceae). Depending on

60 6 2a 2b ~3 cross -section 10 ~1 Fig. 16 Schematic drawings to illustrate some descriptive terms. 1 = tier; 2 = distal shield (2a = first cycle; 2b = second cycle); 3 = proximal shield; 4 = distal margin cycle; 5 = proximal margin cycle; 6 = inner margin cycle; 7 = outer margin cycle; 8 = central process; 9 = bar; 10 = plate; 11 = perforation; 12 = opening.

61 Po d orha bdaceae 8 oblique proximal view ~3 cross-sect ion Vii oblique proximal view (outer margin cycle not drawn)

62 their position they form a proximal or a distal shield. In some genera of the Coccolithaceae the distal shield consists of two cycles, the outer one of which is the first cycle of the distal shield and the other the second cycle of the distal shield. The term tiers is used, when the thin, but broad cycles are attached on top of another and their number is more than two (Arkhangelskiellaceae). Such tiers, generally three or four are numbered from distal to proximal. The central area In the central area all kinds of structures may be either present, or there may be no structure at all. The "Round Table Conference" defined most components forming the central structure, such as bar, central process, perforation and opening. A structure that closes the whole central area or major parts there of is referred to here as a plate. Distal margin cycle: Cycle of elements at the distal side of the margin, which is not subdivided in tiers or shields. Inner margin cycle: Cycle of the margin generally consisting of thin and high elements, bordering the central area and attached to the inner side of one or more margin cycles. Outer margin cycle: Cycle of the margin generally consisting of thin and high elements forming the outer side of the margin and attached to the outer side of one or more cycles. Plate: Thin and extended sheet-like structure, often perforated, closing the whole central area. Proximal margin cycle: Cycle of elements at the proximal side of the margin, which is not subdivided in tiers or shields.

63 The study of the evolution of Cretaceous calcareous nannoplankton is still in its infancy. Bukry (1969) indicated some evolutionary trends based on observations with the electron microscope. Forchheimer (1972) pointed out that Broinsonia parca developed out of Broinsonia lacunosa. This lineage was also studied by Lauer (1975), who worked on the evolution of the Arkhangelskiellaceae. In this chapter only those lineages will be described, which were studied in detail. Trends, which have been observed only, but not worked out in detail, have been indicated in the chapter on taxonomy. Verbeek (197 6b) indicated that Ceratolithoides kamptneri developed from Ceratolithoides aculeus. After a detailed study it became clear that this evolution is much more complicated than was expected. For the reconstruction of this lineage the samples of El Haria section of the composite sequence of El Kef were used. A distribution chart of the different types recognized is given in fig. 17 and the types are pictured on plate I. Because the specimens had to be observed from alle sides, mobile mounts were used. The oldest forms of Ceratolithoides aculeus recorded in the samples AFN 182, AFN 183 and AFN 184 are cone-shaped and constructed of two layers. The layer at the base of the cone is low, petaloid in outline and composed of six subequal elements. Each basal element supports a wedgeshaped element of the high top-layer (type I; pi. I, fig. 1-3). In the course of evolution two opposite top elements rotate slightly in the same direction, so that they become supported by the adjacent base element and the base elements originally supporting these two top elements become free. All other elements of the cone do not move relatively to one another (type II; pi. I, fig. 4). These forms of Ceratolithoides aculeus are only present in sample AFN 184, though in sample AFN 183 rare specimens were observed, in which some indication for such a rotation has been found. In the next type the two free base elements have disappeared (type III; pi. I, fig. 5; for easier comparison the base elements have been numbered). Specimens assigned to this type were recorded in sample AFN 188 only. In the next step the two base elements, which support two top elements, become reduced in size

64 and one of these two top elements disappears (type IV; pi. I, fig. 6-7). Generally the four remaining top elements are slightly curved, so that their tops are found above the center of the base. Type IV has been observed in sample AFN 188 and in all samples from younger sediments with the exception of AFN 202. The two base elements, which were not involved so far, become elongated and the length of the top elements decreases slightly. In sample AFN 192 the first specimens occur, in which the basal part is about as high as the top part. These variants still belong to type IV. In sample AFN 199 the variation in Ceratolithoides aculeus becomes wider, because many specimens were found in which the length of the top Ul Ul W W...J (9 0- <l: f- L: Ceratolithoides 0;: Ul <l: aculeus '" c: Ul Q. en ::J H 1:1 a e! PI ~ E "::J QI.;;- n QI.;;- n QI... n» n QI QI...».;;- n QI.;;- n 0 " '- cs c.j AFN " " z <l: - f- " I U - 0:: f- Ul " " <l: " <l: L: " " " " z <l: " z " <l: 0-2 " <l: u " 183 +? " 182 +

65 decreased strongly. The top is distinctly shorter than the base (type V; pi. I, fig. 8-10). Sometimes the four top elements have almost disappeared (pi. I, fig. 11). Only these forms with such a reduced top part have been assigned to Ceratolithoides kamptneri (cf. Bramlette and Martini, 1964, p. 308, pi. 5, fig ). In all forms discussed there is almost no angle between the elements of the top and those of the base. In Ceratolithoides arcuatus Prins and Sissingh such an angle is distinct. This species was found to be rare in the samples AFN 195, AFN 196, and AFN 199. Transitional forms between Ceratolithoides arcuatus and Ceratolithoides aculeus are present in these samples. In all samples starting from sample AFN 192 specimens were found with only two blocky elements in the base and four rather small top elements (pi. I, fig. 12). Between these forms, which are listed as type VI, and Ceratolithoides aculeus no transitional forms were found. Eiffellithus For the reconstruction of the evolutionary lineages in the genus Eiffellithus specimens from Albian and Cenomanian sediments of the sequence of EI Burrueco and material from the Kat el Hamra section of EI Kef were selected for further study. The angle a between the longer bar of the central structure and the major axis of the elliptical disc was measured (fig. 18). The oldest forms recorded in the section of EI Burrueco in sample SP 411-SP 414 show an angle a between 0 and 20 (fig. 18); the average angle increases slowly. In sample SP 411 most specimens show an open central area, whereas in samples SP 412-SP 414 the central area is commonly half closed by a broadening of the inner margin cycle. The number of specimens with a fully closed central area tends to increase. These assemblages are assigned to Vekshinella angusta. In sample SP 415 many more specimens have a closed central area and a is always greater than 20. Because of the latter feature these assemblages are assigned to Eiffellithus turriseiffeli, which species is the oldest representative of the genus Eiffellithus. From sample SP 415 upward to sample SP 310 the average a increases slowly to about 50 and almost every specimen has a closed central area. As the shorter bar does not rotate very much the bars finally show a symmetrical X-pattern. Such specimens conform to the typical Eiffellithus turriseiffeli. Up to sample Kef 11 of the Kat el Hamra section specimens of Eiffellithus turriseiffeli are not different from those of the Lower Cenomanian part of the sequence of EI Burrueco. From Kef 12 upward the shorter bar

66 "L ;0 o o central area open Q central orea holf open central area closed., dilill~ 0- ;Ql~e323" o.'8 0;:34" ex The change of the angle ex in Eiffellithus measured in the Albian-Cenomanian interval of the El Burrueco section.

67 starts to rotate. The angle {3 between the major axis and the shorter bar was measured from sample Kef 9 upward (fig. 19). Between the samples Kef 11 and Kef 12 this angle becomes more variable because it decreases in part of the population as far down as 15. This rotating bar becomes elongated. Although the "shorter" bar gets longer than the "longer" bar, these bars may be differentiated in crosspolarized light with the aid of the gypsum plate. The specimens with such a smaller {3 value show bars with slightly bifurcated ends. This trend could be followed to sample Kef 15, in which specimens occur with bars with strongly bifurcated ends and a smallest {3 value of 5. In samples from younger sediments than Kef 15 up to the extinction level of forms with such a small {3 the same wide array of {3 values was measured as in sample Kef 15. Specimens with {3 values of less than 20 have been assigned to Eiffellithus eximius and those with more than 20 remain in Eiffellithus turriseiffeli. In the Upper Maastrichtian sediments of El Haria Eiffellithus parallelus is characterized by short and broad bars, which show the X-shaped pattern similar to that of the typical Eiffellithus turriseiffeli. Although no transitional forms were found between both species it seems likely, that Eifellithus parallelus developed from Eiffellithus turriseiffeli. (See addendum at the end of this volume, p. 124). '0 lnmdh'c'" o...,.~ /3

68 In the genus Broinsonia an evolutionary trend was found which could be shown by measurements. The width of the margin increases relative to the width of the coccolith. This trend corresponds to the development of Broinsonia parca from Broinsonia lacunosa, which evolution was already Fig. 20 The b/a ratio in the Broinsonia lacunosa-broinsonia parca group in the Oued Zerga and El Haria sections (Kef).

69 indicated by Forchheimer (1972) and described in more detail by Lauer (1975). The lineage was elaborated from material of the Oued Zerga section. The most important feature, which was used, is the ratio between the width of the margin (a) and the width of the central area (b). In fig. 20 only the results of the Oued Zerga samples 44 to 47 are given, because in the other samples with Broinsonia lacunosa from older sediments of this section the ratios are the same as in sample Kef 44. Lauer (1975) reports also an increase in size, an increasing difference in size of the tiers in the margin and a reduction in the number of perforations in the central structure. These trends have been recognized in the present material as well. The increase of size is indicated in fig. 21. The other two features are too vague for precise observations, because the changes in the margin are too small to be measured accurately and the perforations of the Santonian specimens are often overgrown with secondary calcite. As shown in fig. 20 the b/a ratio increases rapidly in the suite of samples Kef 44 to Kef 47, just as the total width of the coccoliths (fig. 21). Broinsonia parca is defined arbitrarily by a b/a ratio of 1.0 or smaller, and Broinsonia lacunosa by a b/a ratio greater than 1.0. Also the differences in diameter of the tiers of the margin increases more strongly, than anywhere else in the section. Lauer (1975) distinguished in the Campanian sediments of Central Oman four other types in Broinsonia parca based on the b/a ratio and the decreasing number of perforations in the central structure. In the Campanian A FN 190 AFN 189 A FN 188 A FN 184 A FN 183 A FN 182 A FN 181 Kef 47 Kef 46 Kef 45 Kef 44 0

70 material of El Haria section it is often impossible to count the number of perforations, because of the overgrowth with secondary calcite, so that this trend cannot be checked. In order to compare our Broinsonia parca from the Campanian with the four types of Lauer (1975) the bl a ratio of Broinsonia parca was measured in the section of El Haria (fig. 20). Unimodal distributions were obtained without systematic changes along the column. We see no reason to subdivide these Campanian forms in another four types.

71 Only those species are dealt with which can be recognized in both the light microscope and the electron microscope. The recommendation of Perch-Nielsen (1968) to select species on characteristics, which are only visible in the electron microscope and ignoring the more restricted possibilities of the light microscope, was not followed. As a result several species are lumped together in some cases. For example ornamentation in perforations is not recognized as a significant feature for species distinction; especially for the Arkhangelskiellaceae this procedure reduces the number of species recognized. The general construction of the margin is of primary importance to discriminate families, and other features of the margin and the composition of the central structure for selecting genera. Most of the Mesozoic genera have been listed by Noel (1971), who also gives a key to these genera. Minor characteristics of the central structure were generally used for the designation of species. For taxonomic problems the I.C.B.N. and the "Annotated Indexes" of Loeblich and Tappan ( ) were followed. If references were not available the "Catalogue of Calcareous Nannofossils" (Farinacci, ) was consulted. No attention was paid to specimens with a size smaller than about 2-3/1. The families are dealt with in alphabetic order, which order does not imply any relation between the successive families. The composite ranges are mainly based on Thierstein (1973) and the results of the present study. If necessary the ranges are completed with data from other references. Forchheimer (1972, 1974) published many species typical for the Upper Cretaceous to have a level of appearance in the Lower Cretaceous. As she does not report species characteristic for Lower Cretaceous sediments only, these ranges are considered doubtful and they were therefore ignored. Family ARKHANGELSKIELLACEAE Bukry, 1969 Remarks: To this family belong the genera with complicated margins consisting of three or four rim tiers and a central structure which is divided in four quadrants by sutures.

72 Genus Arkangelskiella Vekshina, 1959 Type species: Arkhangelskiella cymbiformis Vekshina, 1959 Remarks: This genus is characterized by a margin composed of three or four rim tiers, of which the two most distally placed ones are of about the same size, closely appressed and constructed of the same number of elements. The proximal rim tiers are narrower. The margin and the central structure are both rather flat in distal view in comparison with the genera Gartnerago and Kamptnerius. In the latter the central structure is concave and the margin convex in distal view. In these two genera and in the genus Broinsonia, the distal rim tier is narrower than the underlying rim tier and even in the light microscope this distal rim tier is distinct. In the genus Arkhangelskiella this distal rim tier is indistinct when the light microscope is used. Arkhangelskiella cymbiformis Vekshina (pi. 2, fig. 3-4) Arkhangelskiella cymbiformis Vekshina, 1959, p. 66, pi. 2, fig. 3a-b; Stradner, 1963, p. 12, pi. 1, fig. 4a-b; Bramlette and Martini, 1964, p. 297, pi. 1, fig. 3-9; Reinhardt, 1965, p. 31, pi. 2, fig. 6; Reinhardt, 1966, p. 31, pi. 6, fig. 1-3; pi. 22, fig ; Gartner, 1968, p. 38, pi. 1, fig. 1-6; pi. 4, fig. 1-4; pi. 6, fig. la-c; Bukry, 1969, p. 21, pi. 1, fig. 1-3; Manivit, 1971, p. 103, pi. 1, fig Remarks: The difference between A. cymbiformis and Arkhangelskiella specillata is in the number of perforations. The first has five or less perforations in each quadrant of the central structure, and the latter more than five. In the Kef section the specimens of A. cymbiformis often show five perforations in each quadrant of the central structure, but in the Burrueco section perforations are usually not visible, probably due to overgrowth with secondary calcite. Composite range: Campanian-Maastrichtian. Arkhangelskiella specillata Vekshina (pi. 2, fig. 1-2) Arkhangelskiella specillata Vekshina, 1959, p. 67, pi. 2, fig. 5; Gartner, 1968, p. 39, pi. 9, fig. 6-7; pi. 11, fig. 4; Cepek and Hay, 1969a, pi. 4, fig. 10; Manivit, 1971, p. 104, pi. 1, fig Arkhangelskiella specillata ethmopora Bukry, 1969, p. 21, pi. 1, fig Arkhangelskiella ethmopora Bukry. Cepek and Hay, 1969a, pi. 4, fig. 11; Cepek and Hay, 1969b, pi. 20, fig. 6; Manivit, 1971, p.103, pi. 1, fig Remarks: This species can be differentiated from A. cymbiformis by having

73 more than five perforations in each quadrant of the central structure and from Gartnerago obliquum by the random arrangement of the perforations in each quadrant. Bukry (1969) described A. specillata ethmopora as a subspecies, characterized by little spokes in the perforations. As stated in the introduction of this chapter this is not a feature, on which a new species can be based. Cepek and Hay (19 69a, b) discriminated A. ethmopora from A. specillata without any comment and Manivit (1971) gave as the differential diagnosis the smaller diameter of the perforations in A. ethmopora. In our investigations forms with large and small perforations were found to have the same range. The diameter of the perforations probably depends on the amount of overgrowth with secondary calcite. For these reasons both forms are considered to be conspecific. Composite range: Campanian-Maastrichtian. Genus Broinsonia Bukry, 1969 Type species: Broinsonia dentata Bukry, 1969 Remarks: This genus differs from the other genera of the family Arkhangelskiellaceae by a first rim tier of the margin composed of large and sometimes irregular elements with radial ridges. In the light microscope this tier appears as a smooth plate with high birefringence in cross-polarized light. The sutures, which divide the central structure in four quadrants are situated on prominent bars in some of the species of this genus. Broinsonia enormis (Shumenko) Manivit (pi. 2, fig. 5) Arkhangelskiella enormis Shumenko, 1968, partim, p. 33, pi. 1, fig. 2-3, non pi. 1, fig. 1. Broinsonia bevieri Bukry, 1969, p. 21, pi. 1, fig. 8-10; Noel, 1970, p. 75, pi. 23, fig. 1,5; pi. 24, fig. 1-5; pi. 25, fig. 1-3,5; Roth and Thierstein, 1972, pi. 14, fig , Aspidolithus angustus Noel, 1969a, p. 196, pi. 1, fig Broinsonia enormis (Shumenko) Manivit, 1971, p. 105, pi. 1, fig Remarks: In our material B. enormis and Broinsonia lata are the only two species of the genus Broinsonia without perforations in the central structure. They can easily be differentiated, because B. enormis has a much broader margin and in cross-polarized light the longest suture in its central structure is more distinct than the other, whereas in B. lata both sutures are equally vague. Composite range: Albian-Campanian.

74 Broinsonia furtiva Bukry (pi. 2, fig. 6-7) Broinsonia furtiva Bukry, 1969, p. 22, pi. 2, fig. 7-8; Thierstein, 1974, partim, p. 637, pi. 10, fig. 7-14; pi. 11, fig. 1-4, non pi. 11, fig. 5-8; Verbeek, 1976b, p. 143, pi. 1, fig. 8. Remarks: In the present paper B. furtiva and Broinsonia signatil are the two species of the genus with bars in the central structure. B. furtiva was differentiated from B. signata by its narrower bars, in which the sutures are situated, and its large and irregular perforations in each quadrant plate. B. signata has open quadrants, or one or two little spokes in each quadrant parallel to the shorter bar. All other species of the genus Broinsonia with prominent bars have a larger number of spokes in the quadrants or they have finely perforated shields. Composite range: Coniacian-Campanian. Broinsonia lacunosa Forchheimer (pi. 2, fig. 8-9) Arkhangelskiella cymbiformis Vekshina, Stover, partim, p. 137, pi. 1, fig. 18, non pi. 1, fig. 17. Broinsonia parca (Stradner) Bukry, 1969, partim, p. 23, pi. 3, fig. 5-8, non pi. 3, fig. 3-5, Broinsonia lacunosa Forchheimer, 1972, p. 25, pi. 2, fig. 1; Verbeek, 1976b, p. 144, pi. 2, fig. 2. Broinsonia furtiva Bukry. Thierstein, 1974, partim, p. 637, pi. 11 fig. 5-8, non pi. 10, fig. 7-14; pi. 11, fig Remarks: Broinsonia lacunosa Forchheimer is characterized by a rather narrow margin and a large central structure with rather indistinct sutures and distinct perforations. The oldest forms of this species have about seven perforations in each quadrant of the central structure, younger forms normally three. The width of the central structure decreases in younger forms. B. lacunosa is probably synonymous with Aspidolithus sp. 1 and sp. 2 of Lauer (1975) and it is the ancestor of Broinsonia parca (Stradner). An evolutionary trend was recognized in the Kef and Burrueco section (Verbeek, 1976b). B. lacunosa differs from B. parca in having a central area which is broader than the margin, more distinct perforations in the central structure and a less prominent ridge, or none at all, around the central area at the distal side of the margin. Composite range: Lower Santonian-Lower Campanian. Aspidolithus latus Noel, 1969a, p. 196, pi. 2, fig. 1-2, textfig. 2a-b. Broinsonia lata (Noel) Noel, 1970, p. 76, pi. 23, fig. 2a-b; Roth and Thierstein, 1972, pi. 14, fig ; Thierstein, 1973,p. 35, pi. 6, fig ; Griin and Allemann, 1975, p. 154, pl.1, fig. 1-4.

75 Remarks: This species is characterized by a narrow margin and a large central structure without perforations and distinct sutures dividing the central structure in quadrants. Griln and Allemann (1975) recorded B. lata in Berriasian sediments of Southern Spain and therefore it is the oldest known representative of the family Arkhangelskiellaceae. In our material it was only found in the Albian and Cenomanian rocks of 1 Burrueco and in the Cenomanian sediments of 1 Kef. Thierstein (1973) gives a range of Middle Albian to Campanian. Composite range: Berriasian?, Middle Albian-Campanian. Broinsonia parca (Stradner) Bukry (pi. 2, fig ) Arkhangelskiella parca Stradner, 1963, p. 10, pi. 1, fig. 3, 3a; Bramlette and Martini, 1964, p. 298, pi. 2, fig. 1-2; Gartner, 1968, p. 38, pi. 8, fig. 4-5; pi. 11, fig. 2a-c; Perch-Nielsen, 1968, p. 61, pi. 21, fig. 1-4, textfig. 26e-f, 27. Arkhangelskiella cymbiformis Vekshina. Stover, 1966, partim, p. 137, pi. 1, fig. 17, non pi. 1, fig. 18. Broinsonia parca (Stradner) Bukry, 1969, partim, p. 23, pi. 3, fig. 3-5, non pi. 3, fig. 6-10; Noel, 1970, p. 77, pi. 23, fig. 3, textfig. 18; Manivit, 1971, partim, p. 106, pi. 2, fig. 2--':8, non pi. 2, fig. 1; Perch-Nielsen, 1972, p. 1007, pi. 22, fig. 5; Verbeek, 1976b, p. 144, pi. 2, fig. 6. Aspidolithus parcus (Stradner) Noel, 1969a, p. 196, pi. 1, fig Remarks: B. parca has a margin, which is as broad as, or broader than the central area. The central structure shows none to three perforations in each quadrant. A prominent distal ridge on the margin around the central area is present. B. parca evolved from B. lacunosa and seems to be synonymous with Aspidolithus sp. 3, sp. 4 and sp. 5 of Lauer (1975). Composite range: Campanian-Maastrichtian. Broinsonia signata (Noel) Noel (pi. 2, fig. 12) Arhangelskiella enormis Shumenko, 1968, partim, p. 33, pi. 1, fig. 1, non pi. 1, fig Aspidolithus signatus Noel, 1969a, p. 197, pi. 2, fig Broinsonia signata (Noel) Noel, 1970, p. 78, pi. 25, fig. 4-6; Roth and Thierstein, 1972, pi. 13, fig ; pi. 14, fig Acaenolithus undatus Black, 1973, partim, p. 58, pi. 21, fig. 1-2,4-5, non pi. 21, fig. 3. Remarks: B. signata is distinguished by a central structure composed of a cross of rather narrow bars, on which the sutures are situated, parallel to the axes of the elliptical disc. In the four open quadrants one to three little spokes may occur parallel to the shorter axis. Thierstein (1973) gives a range from Middle Albian-Upper Campanian, but in our material this species was not found at levels higher than Lower Coniacian. Composite range: Middle Albian-Upper Campanian.

76 Genus Gartnerago Bukry, 1969 Type species: Arkhangelskiella concava Gartner, 1968 (= Gartnerago obliquum (Stradner, 1963) Reinhardt, 1970b). Remarks: This genus is distinguished by a distal rim tier, which is narrower than the underlying one, but with the same number of elements. These two tiers are not closely appressed and concave in distal view. The distally convex central structure is divided into four quadrants by sutures, which are lined at both sides by one or more rows of perforations. These rows of perforations are not found in any other genus of the family. The other genera show perforations which are spread over the central structure. Gartnerago obliquum (Stradner) Reinhardt (pi. 3, fig. 1-2) Arkhangelskiella obliqua Stradner, 1963, p. 12, pi. 1, fig. 2, 2a. Ahmuellerella oblata Reinhardt, 1965, p. 31, pi. 1, fig. 2. Arkhangelskiella inclinata Reinhardt, 1965, p. 31, pi. 2, fig. 5. Discolithus segmentatus Stover, 1966, p. 143, pi. 3, fig. 3-6; pi. 8, fig. 19. Arkhangelskiella concava Gartner, 1968, p. 37, pi. 14, fig. 2-3; pi. 16, fig. 5-7; pi. 17, fig. 7; pi. 18, fig ; pi. 19, fig. 6; pi. 21, fig. 7; pi. 22, fig Arkhangelskiella costata Gartner, 1968, p. 37, pi. 8, fig. 1-3; pi. 11 fig. 1; pi. 28, fig. 2. Arkhangelskiella magnacava Gartner, 1968, p. 38, pi. 18, fig ; pi. 22, fig. 9. Arkhangelskiella scapha Gartner, 1968, p. 39, pi. 14, fig. l;pi. 15, fig. l;pi. 17, fig. 8;pI. 20, fig Arkhangelskiella omamentus (Caratini) Manivit, 1968, p. 278, pi. 1, fig. 2. Gartnerago concavum (Gartner) Bukry, 1969, p. 24, pi. 4, fig. 2-6; Forchheimer, 1972, p. 26, pi. 3, fig. 5. Gartnerago costatum costatum (Gartner) Bukry, 1969, p. 24, pi. 4, fig Gartnerago costatum porolatum Bukry, 1969, p. 24, pi. 4, fig Gartnerago sp. Bukry, 1969, p. 25, pi. 5, fig Laffitius obliquus (Reinhardt) Noel, 1969a, p. 197, pi. 3, fig. 1-5, textfig. 3a-b. Discolithus octocentralis Stover. Cepek, 1970, p. 241, pi. 22, fig. 7-8; pi. 26, fig. 6. Gartnerago obliquum (Stradner) Reinhardt, 1970b, p. 66; Noel, 1970, p. 79, pi. 26, fig. 1-7; Manivit, 1971, p. 106, pi. 2, fig. 9-12; Forchheimer, 1972, p. 28, pi. 4, fig. 5-6; Thierstein, 1974, p. 640, pi. 5, fig. 3-9; pi. 6, fig. 2; pi. 7, fig. 1-5,7-10. Gartnerago costatum (Gartner) Forchheimer, 1972, p. 27, pi. 4, fig Gartnerago porolatum (Bukry) Forchheimer, 1972, p. 28, pi. 3, fig Gartnerago segmentatum (Stover) Thierstein, 1974, p. 640, pi. 5, fig. 1-2; pi. 6, fig. 1,3-10; pi. 7, fig. 6. Remarks: Thierstein (1974) recognized two species: G. obliquum with one row of perforations and G. segmentatum without perforations; the specimens of G. segmentatum are strongly overgrown with secondary calcite. Both species have the same range and their ratio depends on the preservation of the sample. The same results were found in this study. For these reasons the suggestion of Theirstein (1974, 1976) that both species are conspecific is followed here. Because the presence or absence or perforations are of no

77 diagnostic value in this species, the shape and presence of spokes in the perforations are considered of no taxonomic value either. This means that there remain only two species in the genus Gartnerago, G. obliquum and Gartnerago striatum, a species not recorded in the present study. Furthermore a Gartnerago sp. is recognized. Composite range: Upper Cenomanian-Maastrichtian. Gartnerago sp. (pi. 3, fig. 3) Remarks: Gartnerago sp. differs from G. obliquum by its narrow margin, its distinct sutures and its smaller size. No perforations were observed. Gartnerago sp. was only found in sample SP 323 of the Burrueco section. Composite range: Middle to Upper Albian. Genus Kamptnerius Deflandre, 1959 Type species: Kamptnerius magnificus Deflandre, Remarks: The genus is easily recognized by its asymmetric first or second rim tier. The sutures of the distally convex central structure are vague. The rim is distally concave. Thierstem (1974) showed that the central structure is always a perforated plate and that the presence of ribs in the central area is due to overgrowth with secondary calcite. Only the presence or absence of a wing at the margin is considered diagnostic to discriminate two species. Kamptnerius magnificus Deflandre (pi. 3, fig. 4-5) Kamptnerius magnificus Deflandre, 1959, partim, p. 135, pl 1, fig. 1, non pl 1, fig. 2-4; Gartner, 1968, partim, p. 39, pl 2, fig. 1; pl 3, fig. 7; pl 6, fig. 10; pl 10, fig. 13; pl 15, fig. 10; pl 16, fig. 17, non pl 2, fig. 2; pl 10, fig ; pl 16, fig ; pl 17, fig ;pL 21, fig. 12; Aberg, 1968, partim, p. 5, pl 3, fig. 1-2,4, textfig. 3, non pl 3, fig. 3; Hoffmann, 1970, p. 859, pl 7, fig. 2; Noel, 1970, partim, p. 82, pl 27, fig. 2; pl 28, fig. 3, non pl 27, fig. 1,3-5; pl 28, fig. 1-2, 4~5. Kamptnerius punctatus Stradner, 1963, p. 13, pl 2, fig. 3, 3a; Bukry, 1969, p. 26, pl 6, fig. 4-5; Manivit, 1971, p. 108, pl 14, fig Kamptnerius? minimus Reinhardt, 1964, p. 752, pl 1, fig. 5. Kamptnerius aff. K. magnificus Deflandre. Bramlette and Martini, 1964, pl 2, fig Kamptnerius percivalii Bukry, 1969, partim, p. 25, pl 6, fig. 3, non pl 6, fig Kamptnerius granatus Hoffmann, 1970, p. 859, pl 4, fig. 3, textfig. 4. Remarks: This species is characterized by an asymmetrical margin, with a distinct sideward extending wing, which differentiaties this species from Kamptnerius tabulatus. A subdivision based on the number of perforations

78 in the central structure is not possible (Thierstein, 1974, 1976). Composite range: Lower Campanian-Maastrichtian. Kamptnerius tabulatus Perch-Nielsen (pi. 3, fig. 6-7) Kamptnerius magnificus Deflandre, 1959, partim, p. 135, pl. 1, fig. 2~4, non pl. 1, fig. 1; Stradner, 1963, p. 13, pl. 2, fig. 2, 2a; Bramlette and Martini, 1964, p. 301, pl. 2, fig. 3; Stover, 1966, p. 144, pi. 4, fig ; Gartner, 1968, partim, p. 39, pi. 2, fig. 2; pi. 10, fig ; pi. 16, fig ; pi. 17, fig ; pi. 21, fig. 12, non pi. 2, fig. 1; pl. 3, fig. 7; pi. 6, fig. 10; pi. 10, fig. 13; pi. 15, fig. 10; pi. 16, fig. 17; Perch-Nielsen, 1968, p. 41, pl. 6, fig. 1,3,5, textfig. 16; Aberg, 1968, partim, p. 5, pl. 3, fig. 3, non pi. 3, fig. 1-2,4, textfig. 3; Noel, 1970, partim, p. 82, pi. 27, fig. 1,3-5; pi. 28, fig. 1-2,4-5, non pi. 27, fig. 2; pl. 28, fig. 3; Manivit, 1971, p. 107, pl. 14, fig ; pl. 20, fig. 11; Thierstein, 1974, p. 640, pl. 8, fig. 1-9; pl. 9, fig. 1-11; Thierstein, 1976, p. 351, pl. 1, fig. 1-2; pl. 4, fig Kamptnerius? tabulatus Perch-Nielsen, 1968, p. 42, pl. 6, fig. 4. Kamptnerius magnificus magnificus Deflandre. Bukry, 1969, p. 25, pl. 5, fig Kamptnerius magnificussculptus Bukry, 1969, p. 25, pl. 5, fig Kamptnerius percivalii Bukry, 1969, partim, p. 25, pl. 6, fig. 1-2, non pl. 6, fig. 4. Kamptnerius pertusus Forchheimer, 1972, p. 30, pl. 5, fig Kamptnerius punctatus Stradner. Forchheimer, 1972, p. 30, pl. 4, fig. 1,3; pl. 5, fig Remarks: K. tabulatus is recognized by a more or less asymmetrical margin without a distinct sideward extending wing. Composite range: Middle Turonian-Maastrichtian. Family BRAAR UDOSPHAERACEAE Deflandre, 1947 Remarks: The family Braarudosphaeraceae includes the genera, in which the coccoliths are composed of five radially arranged elements of the same size and shape. Genus Braarudosphaera Deflandre, 1947 Type species: Pontosphaera bigelowi Gran and Braarud, Remarks: The genus Braarudosphaera is recognized by its five marginally convex elements, whereas the other genus of the family, Micrantolithus, shows elements, which are marginally concave or straight, but never convex. Braarudosphaera bigelowi (Gran and Braarud) Deflandre (pi. 3, fig. 8) Pontosphaera bigelowi Gran and Braarud, 1935, p. 388, fig. 67. Braarudosphaera bigelowi (Gran and Braarud) Deflandre, 1947, p. 439, fig Braarudosphaera regularis Black, 1973, p. 91, pi. 28, fig. 10.

79 Remarks: This species is characterized by its pentagonal outline and its five elements which are not imbricate. Braarudosphaera africana differs from B. bigelowi by a star-shaped outline. Composite range: Lower Berriasian-Recent. Remarks: The specimens found in our material may be poorly preserved specimens of B. bigelowi, but they resemble B. discula in their oval to circular outline. Composite range: Upper Albian-Maastrichtian. Family CALCIOSOLENIACEAE Kamptner, 1927 Remarks: The family contains coccoliths, with an angular margin composed of a single cycle and a central structure generally consisting of a set of parallel bars. Genus Scapholithus Deflandre, 1954 Type species: Scapholithus fossilis Deflandre, Remarks: This genus includes elongated parallelogram-shaped forms with a rather narrow margin and a central structure of small parallel bars. Scapholithus sp. Remarks: Our specimens show a margin similar to that of Scapholithus fossilis, but a central structure was not observed. Composite range: Albian-Maastrichtian. Family COCCOLITHACEAE Kamptner, 1927 Remarks: In this family are included all coccoliths with a margin constructed of two shields and without a central process. Generally the proximal shield is smaller than the distal shield. The central structure is of simple construction or absent. Genus Bidiscus Bukry, 1969 Type species: Bidiscus cruciatus cruciatus Bukry, 1969 (= Tremalithus ignotus Gorka, 1957).

80 Remarks: Three of the genera of the family Coccolithaceae recorded in our material have a circular outline. Two of them have one cycle of elements in the distal shield: Bidiscus and Markalius. The third genus Cyclagelosphaera has two cycles in the distal shield. Bidiscus is recognized by an almost flat distal side and a small central area, whereas Markalius shows a rather large central structure which is distally depressed together with a part of the margin. Bidiscus differs from Discorhabdus by the lack of a central process. Bidiscus ignotus (Gorka) Hoffmann (p. 3, fig. 9) Tremalithus ignotus Gorka, 1957, p. 272, pi. 2, fig. 9. Bidiscus cruciatus cruciatus Bukry, 1969, p. 27, pi. 6, fig Bidiscus cruciatus multicruciatus Bukry, 1969, p. 27, pi. 6, fig. 12; pi. 7, fig Biscutum ignotum (Gorka) Reinhardt, 1970a, partim, p. 28, pi. 1, fig. 1-3, textfig , non pi. 1, fig Bidiscus ignotus (Gorka) Hoffmann, 1970a, p. 862, pi. 7, fig. 1. Remarks: B. ignotus differs from Bidiscus rotatorius by a cycle of four elements in the central structure. B. rotatorius has a very small open central area and a broad inner margin cycle of about 13 elements. Composite range: Albian-Maastrichtian. Bidiscus rotatorius Bukry (pi. 3, fig. 10) Bidiscus rotarorius Bukry, 1969, p. 27, pi. 7, fig Discorhabdus rotatorius (Bukry) Thierstein, 1973, p. 42, pi. 5, fig Remarks: The broad inner margin cycle is characteristic for this species and shows a stronger birefringence than the rest of the margin in crosspolarized light. Composite range: Lower Berriasian-Campanian. Genus Biscutum Black, 1959 Type species: Biscutum testudinarium Black, 1959 (= Discolithus constans Gorka, 1957). Remarks: The genera Biscutum and Watznaueria are the only genera in Cretaceous sediments belonging to the family Coccolithaceae with an elliptical outline and a small central area. Biscutum differs from Watznaueria by having one cycle of elements in the distal shield.

81 Biscutum constans (Gorka) Black (pi. 4, fig. 1) Discolithus constans Gorka, 1957, p. 279, pi. 4, fig. 7. Biscutum testudinarium Black, in Black and Barnes. 1959, p. 325, pi. 10, fig. 1. Biscutum castrorum Black, in Black and Barnes, 1959, p. 326, pi. 10, fig. 2. Cribrosphaerella tectiforma Reinhardt, 1964, p. 758, pi. 2, fig. 4. Coccolithus polycingulatus Reinhardt, 1965, p. 39, pi. 3, fig. 4. Coccolithus oregus Stover, 1966, p. 139, pi. 1, fig. 8-9; pl. 8, fig. 4. Biscutum constans (Gorka) Black, 1967, p. 139; Perch-Nielsen, 1968; p. 78, pl. 27, fig. 1-11, textfig. 39;Noel, 1970, p. 91, pl. 33, fig. 1-10; pl. 34, fig. la-g; Thierstein, 1973, p. 41. Biscutum blacki Gartner, 1968, p. 18, pi. 1, fig. 7; pi. 6, fig. 2; pi. 8, fig. 8-10; pi. 11, fig. 8; pl. 15, fig. 2;pI. 16, fig. 8. Maslovella blackii Pienaar, 1968, p. 366, pl. 69, fig. 1, 5. Maslovella pulchra Pienaar, 1968, p. 366, pi. 69, fig. 3. Biscutum asymmetricum Perch-Nielsen, 1968, p. 80, pl. 23, fig. 2-3, 13-15; Bukry, 1969, p. 27, pi. 7, flg Biscutum? supracretaceum (Reinhardt) Perch-Nielsen, 1968, p. 80, pi. 23, fig Biscutum melaniae (Gorka) Reinhardt, 1969, p. 936, pl. 1, fig. 5. Biscutum multiforme Bukry, 1969, p. 28, pi. 8, fig Biscutum concavum Huh, in Huh and Smith, 1972, p. 21, pi. 2, fig. 9. Biscutum kennedyi Bukry, Forchheimer, 1972, p. 32, pi. 6, flg Biscutum gartneri Black. Black, 1972, p. 27, pi. 2, flg Biscutum martellum Burns, 1976, p. 281, pi. 1, fig Remarks: Following Black (1967), Perch-Nielsen (1963), Nod (1970) and Thierstein (1973) Discolithus cons tans is considered to be the first described species belonging to the genus Biscutum, though both description and figure by Gorka (1957) are vague. In all described species of the genus Biscutum the distal shield is larger than the proximal shield. The number of elements of the distal shield has been used as the most important feature to establish new species, but because of the wide variation per sample none of these species can be really separated from the others by the stated number of elements. This number varies from 14 to 30 in the different descriptions as it does in our material. Other characteristics such as eccentricity of the distal shield and the outline of the proximal shield are considered not diagnostic either because of the strong variation. The described species appear to lack any biostratigraphic value. The other features, on which species have been established are far beyond the possibilities of the light microscope and thus not used. In the electron microscope these features appear to have a rather strong variation as well. As a consequence the genus Biscutum is considered to be monospecific. Composite range: Albian-Maastrichtian.

82 Genus Cruciplacolithus Hay and Mohler, 1967 Type species: Heliorthus tenuis Stradner, Remarks: This tertiary genus is recognized by its bars orientated parallel to the longer and shorter axes of the elliptical disc. Heliorthus tenuis Stradner, 1961, p. 84, textfig Cruciplacolithus tenuis (Stradner) Hay and Mohler, in Hay et ai., 1967, p Remarks: This species differs from all Cretaceous species of the family Coccolithaceae by the cross-shaped central structure. Composite range: Paleocene. Genus Cyclagelosphaera Noel, 1965 Type species: Cyclagelosphaera margereli Noel, Remarks: This genus is restricted to coccoliths with a circular outline and a distal shield consisting of two cycles of elements. Cyclagelosphaera margereli Noel (pi. 4, fig. 3) Cyclagelosphaera margereli Noel, 1965, p. 130, pi. 17, fig. 4-9; pi. 18, fig. 1-2; pi. 20, fig. 2-4; textfig ; Maresch, 1966, pi. 2, fig. 5; Black, 1968, pi. 144, fig. 5; Bukry, 1969, p. 29, pi. 9, fjg. 5-6; Rood, Hay and Barnard, 1971, p. 270, pi. 5, fjg. 8-9; Roth and Thierstein, 1972, pi. 16, fjg Cyclagelosphaera virgatus Black, 1973, p. 75, pi. 25, fjg Cyclagelosphaera casaburensis Black, 1973, p. 76, pi. 25, fjg Remarks: C. margereli differs from Cyclagelosphaera rotaclypeata by the slightly conical shape and the smaller central area. Composite range: Oxfordian-Maastrichtian. Cyclagelosphaera perforata (Perch-Nielsen) Verbeek n. comb. (pi. 4, fig. 2) Markalius perforatus Perch-Nielsen, 1973, p. 317, pi. 1, fig. 9-10; pi. 10, fjg Remarks: Because the distal shield shows two cycles of elements and the coccolith has a circular outline this species belongs to the genus Cyclagelosphaera and not to Markalius, which genus has only one cycle in the distal shield. C. perforata can be recognized by its open central area. Composite range: Maastrichtian.

83 Markalius circumradiatus (non Stover) Perch-Nielsen, 1968, p. 23, pi. 25, fig. 2-7; pi. 26, fig. 1-7, textfig ; Noel, 1970, p. 93, pi. 26, fig Cyclagelosphaera rotaclypeata Bukry, 1969, p. 30, pi. 9, fig Cyclagelosphaeraspecioclypeata Bukry, 1969, p. 30, pi. 9, fig. 9. Remarks: C. rotaclypeata is characterized by its rather large central area and the narrow second cycle of the distal shield. It differs from Cyclagelosphaera baticlypeata Bukry by its larger and closed central area, which is slightly depressed in distal view iust as the adiacent second cycle of the distal shield. It differs from species of the genus Markalius in having two cycles in the distal shield.. Composite range: Campanian-Maastrichtian. Genus Manivitella Thierstein, 1971 Type species: Cricolithus pemmatoideus Deflandre ex Manivit, Remarks: The genus is characterized by a large, open central area and one cycle of elements in the distal shield. Manivitella pemmatoidea (Deflandre ex Manivit) Thierstein (pi. 4, fig. 4) Cricolithus pemmatoideus Deflandre ex Manivit, 1965, p. 192, pi. 2, fig. 8. Cyclolithus gronosus Stover, 1966, p. 140, pi. 1, fig. 1-3; pi. 8, fig. 1. Apertapetragronosa (Stover) Bukry, 1969, p. 26, pi. 6, fig Manivitella pemmatoidea (Deflandre ex Manivit) Thierstein, 1971, p. 480, pi. 5, fig. 1-3; Black, 1973, p. 80, pi. 23, fig Cricolithus? pemmatoideus Deflandre, Manivit, 1971, p. 120, pi. 9, fig. 8-9; pi. 10, fig Manivitellagronosa (Stover) Black, 1973, p. 79, pi. 23, fig Remarks: The narrow inner margin cycle has a smooth border. There IS no indication of a central structure. Composite range: Lower Berriasian-Maastrichtian. Genus Markalius Bramlette and Martini, 1964 Type species: Cyclococcolithus leptoporus Murray and Blackman var. inversus Deflandre in Deflandre and Fert, Remarks: The genus Markalius is distinguished by a circular outline, a distal shield composed of one cycle of elements, and a distal depression consisting of the central area and part of the distal shie l 4-.

84 Coccolithus circumradiatus Stover, 1966, p. 138, pi. 5, fig non Markalius circumradiatus (Stover) Perch-Nielsen, 1968, p. 73, pi. 25, fig. 2-7; pi. 26, fig. 1-7, textfig. 36~37. Cyclagelosphaera chronolitha Bukry, 1969, p. 29, pi. 9, fig Remarks: M. circumradiatus shows many more elements in the distal shield than Markalius inversus (Deflandre), about 40 against 20. Composite range: Berriasian-Maastrichtian. Cyclococcolithus leptoporus Murray and Blackman var. inversus Deflandre, in Deflandre and Fert, 1954, partirn, p. 150, pi. 9, fig. 4~5 non pi. 9, fig Cyclococcolithus astroporus Stradner, in Gohrbandt, 1963, p. 75, pi. 9 fig. 5-7, textfig. 3, fig. 2. Markalius inversus (Deflandre) Bramlette and Martini, 1964, partirn, p. 302, pi. 4, fig. 2-9, non pi. 7, fig. 2. Remarks: This species is characterized in distal view by a central depression with a small diameter and sharp edges. In cross-polarized light the central structure shows a stronger birefringence than the margin. Composite range: Maastrichtian-Eocene. Genus Sollasites Black, 1967 Type species: Sollasites barringtonensis Black, 1967 (= Coccolithus horticus Stradner, Adamiker and Maresch, Remarks: The central structure characteristic for the genus consists of three bars parallel or subparallel with the longer axis of the disc and one bar parallel with the shorter axis. Sollasites horticus (Stradner, Adamiker and Maresch) Cepek and Hay Coccolithus horticus Stradner, Adamiker and Maresch, in Stradner and Adamiker, 1968, p. 337, pi. 2, fig. 4, textfig Sollasites barringtonensis Black, 1967a, pi. 144, fig. 4. Sollasites horticus (Stradner, Adamiker and Maresch) Black, 1968, p. 798, pi. 144, fig. 1-2 (invalid ICBN, art. 33). Costacentrum horticum (Stradner, Adamiker and Maresch) Bukry, 1969, p. 44, pi. 21, fig. 12. Sollasites horticus (Stradner, Adamiker and Maresch) Cepek and Hay, 1969a, p. 325, textfig. 4, fig. 2; Manivit, 1971, p. 117, pi. 24, fig Remarks: S. horticus is rare in our material. It has three bars parallel to the longer axis of the disc, whereas the other species of the genus show one bar parallel and two subparallel to this axis. Composite range: Oxfordian-Campanian.

85 Genus Watznaueria Reinhardt, 1964 Type species: Watznaueria angustoralis Reinhardt, 1964 (= Watznaueria barnesae (Black, 1959) Perch-Nielsen, 1968). Remarks: The genus Watznaueria is characterized by a distal shield consisting of two or three cycles and a rather small central area. Watznaueria barnesae (Black) Perch-Nielsen (pi. 4, fig. 6) Tremalithus barnesae Black, in Black and Barnes, 1959, p. 325, pi. 9, fig Watznaueria angustoralis Reinhardt, 1964, p. 753, pi. 2, fig. 2, textf:tg. 4. Watznaueria barnesae (Black) Perch-Nielsen, 1968, p. 96, pi. 22, f:tg. 1-7; pi. 23, f:tg. 1, 4,5,16, textfig. 32. Remarks: This most frequent nannofossil species of Cretaceous rocks is easily recognized by its slit-like central area without a central structure. The central area of W. barnesae is much narrower than the oval to elliptical central area of Watznaueria prolongata Bukry. Composite range: Oxfordian-Maastrichtian. Watznaueria biporta Bukry (pi. 4, fig. 5) Watznaueria biporta Bukry, 1969, p. 32, pi. 8, f:tg. 8-10; Thierstein 1973, p. 43, pi. 6, fig. 6. Margolatus bornholmnensis (Forchheimer) Black, 1973, p. 81, pi. 24, fig. 6, Remarks: Bukry (1969) described little spokes in the perforations as characteristic for this species. These spokes were not observed and they are not recognized as a feature to separate a species in this study. W. biporta is here recognized as the only species of the genus Watznaueria with a plate with two perforations as the central structure. Watznaueria britannica (Stradner) differs from W. biporta by a larger central area transversed by a bar parallel to the shorter axis of the elliptical disc. W. britannica was not found in our material. Composite range: Lower Berriasian-Campanian. Watznaueria communis Reinhardt (pi. 4, fig. 7) Watznaueria communis Reinhardt, 1964, p. 756, pi. 2, f:tg. 5, textfig. 6; Reinhardt, 1966, p. 17, pi. 4, fig. 3, 5-6; pi. 23, fig. 5, text fig. 3; Rood, Hay and Barnard, 1971, pi. 5, f:tg. 1-4; Thierstein, 1973, p. 43, pi. 6, fig. 17. Remarks: This species is recognized by a rather small central area in which

86 there is sometimes a bar not parallel to one of the axes of the disc. Composite range: Oxfordian-Campanian. Family EIFFELLITHACEAE Reinhardt, 1965 Remarks: This family includes all genera of which the elliptical basal disc has a margin constructed of two or three cycles of elements. There is no subdivision in shields or tiers. Genus Ahmuellerella Reinhardt, 1964 Type species: Ahmuellerella limbitenuis Reinhardt, 1964 (= Ahmuellerella octoradiata (Gorka, 1957) Reinhardt, 1966). Remarks: This genus is characterized by a cone-shaped central structure, which is composed of eight radially or subradially placed bars. Aetinozygus Gartner (1968) is a junior synonym (type species: Tremalithus regularis Gorka, 1957). Ahmuellerella octoradiata (Gorka) Reinhardt (pi. 4, fig. 8) Discolithus octoradiatus Gorka, 1957, p. 259, pi. 4, fig. 10. Zygolithus octoradiatus (Gorka) Stradner, 1963, p. 14, pi. 5, fig. 2-2a: Bramlette and Martini, 1964, p. 304, pi. 4, fig Ahmuellerella limbitenuis Reinhardt, 1964, p. 751, pi. 1, fig. 6; pi. 12, fig. 6; Reinhardt, 1966, p. 24, pi. 14, fig. 1a-b, 3, 4a-b. Ahmuellerella octoradiata (Gorka) Reinhardt, 1966, p. 24, pi. 22, fig. 3-4; Manivit, 1971, p. 93, pi. 1, fig Eiffellithus octoradiata (Gorka) Reinhardt, 1968, p. 25, pi. 2, fig ; pi. 3, fig. 11. Vagalapilla octoradiata (Gorka) Bukry, 1969, p. 58, pi. 33, fig Remarks: The eight bars are near parallel to the axes of the basal disc, which feature distinguishes this species from Ahmuellerella regularis (Gorka), in which the central structure consists of eight radial bars. Composite range: Upper Cenomanian-Maastrichtian. Ahmuellerella regularis (Gorka) n. comb. (pi. 4, fig. 9) Tremalithus regularis Gorka, 1957, p. 246, pi. 2, fig. 4. Rhabdolithus regularis (Gorka) Stradner, 1963, p. 14, pi. 5, fig. 5-5a. Actinozygus regularis (Gorka) Gartner, 1968, p. 23, pi. 3, fig. 12; pi. 5, fig ; pi. 6, fig ; pi. 12, fig. 11. Actinozygus splendens (Deflandre) Gartner, 1968, partim, p. 25, pi. 10, fig. 1 non pi. 5, fig ; pi. 7, fig. 1-2; pi. 11, fig. 15.

87 Reinhardtites mirabilis Perch-Nielsen, 1968, p. 40, pi. 7, fig. 1, textfig. 15. Parhabdolithus regularis (Gorka) Bukry, 1968, p. 53, pi. 30, fig Remarks: This species belongs to the genus Ahmuellerella, because of its cone-shaped central structure, which is composed of eight regularly placed radial bars. The openings between the bars are often closed by thin plates. Composite range: Cenomanian-Maastrichtian. Genus Chiastozygus Gartner, 1968 Type species: Zygodiscus? amphipons Bramlette and Martini, Remarks: The genus Chiastozygus Gartner is characterized by the X-shaped pattern of the bars, that constitute the central structure in an open central area. It differs form the genus Tegumentum Thierstein by the lack of an outer margin cycle. Chiastozygus amphipons (Bramlette and Martini) Gartner (pi. 5, fig. 1) Zygodiscus? amphipons Bramlette and Martini, 1964, p. 302, pi. 4, fig Chiastozygus amphipons (Bramlette and Martini) Gartner, 19'68, p. 26, pi. 8, fig. 1-14; pi. 11, fig. 9; pi. 22, fig ; Bukry, 1969, p. 49, pi. 26, fig. 8-9; Manivit, 1971, p. 92, pi. 4, fig Remarks: C. amphipons differs from Chiastozygus litterarius (Gorka) by the absence of a distinct inner margin cycle. Composite range: Upper Albian-Maastrichtian. Chiastozygus interruptus (pi. 5, fig. 4) Bukry Remarks: This small species has rather broad bars with a very broad base. In cross-polarized light this species shows an extinction pattern which is similar to that of Helicolithus trabeculatus (Gorka), but it can be differentiated by a narrower margin. Composite range: Santonian-Campanian. Chiastozygus litterarius (Gorka) Manivit (pi. 5, fig. 2-3) Discolithus litterarius Gorka, 1972, p. 251, pi. 3, fig. 3. Discolithus fessus Stover, 1966, p. 142, pi. 2, fig ; pi. 8, fig. 16. Chiastozygus plicatus Gartner, 1968, p. 27, pi. 16, fig ; pi. 17, fig. 9; pi. 19, fig. 9; pi. 20, fig. 6; pi. 21, fig. 9; pi. 22, fig. 12; Bukry, 1969, p. 50, pi. 28, fig. 3.

88 Chiastozygus litterarius (Gorka) Manivit, 1971, p. 92, pi. 4, fig. 1-5; Thierstein, 1971, p. 476, pi. 2, fig ; Roth and Thierstein, 1972, pi. 1, fig Helicolithus stillatus Forchheimer, 1972, p. 48, pi. 11, fig. 1-4; pi. 16, fig Remarks: The penetration of the ends of the bars into the proximal side of the inner margin cycle is characteristic for c. litterarius. Composite range: Lower Aptian-Maastrichtian. Genus Discolithina Loeblich and 'Fappan, 1963 Type species: Discolithus vigintiforatus Kamptner, 1948 Remarks: This genus is differentiated from the genus Rhagodiscus Reinhardt by the lack of ridges and a central process in the central structure. Discolithina is a nomen substitum for Discolithus Huxley, which name is invalid (Loeblich and Tappan, 1963). Discolithina spiralis (Pienaar) n. comb. (pi. 5, fig. 5) Remarks: This species was recognized by the spiral-shaped pattern of the elements of the central structure. This feature can only be observed in the electron microscope; in the light microscope it is almost impossible to detect any such structure in this coccolith. Compostie range: Maastrichtian. Genus Eiffellithus Reinhardt, 1965 Type species: Zygolithus turriseiffeli Deflandre, Remarks: The genus Eiffellithus is distinguished from the other genera of the family by bars, which are not parallel with the axes of the elliptical disc and by a closed or almost closed central area. Eiffellithus eximius (Stover) Perch-Nielsen (pi. 5, fig. 6-7) Clinorhabdus eximius Stover, 1966, p. 138, pi. 2, fig ; pi. 8, fig. 15. Eiffellithus turriseiffeli (Deflandre) Reinhardt. Gartner, 1968, partim, p. 26, pi. 16, fig. 1-2; pi. 17, fig. 3; pi. 18, fig. 9-10; pi. 19, fig. 1-2; pi. 23, fig. 8-11; pi. 24, fig. 1-2; pi. 26, fig. 3-4 non pi. 2, fig ; pi. 3, fig. 13; pi. 5, fig. 19; pi. 7, fig. 5; pi. 9, fig. 6-10; pi. 13, fig. 1-2; pi. 23, fig. 7; pi. 25, fig ; Manivit, 1971, p. 90, pi. 11, fig. 1-4, Eiffellithus eximius (Stover) Perch-Nielsen, 1968, p. 30, pi. 3, fig. 8-10; Manivit, 1971, p. 91, pi. 11, fig Eiffellithus augustus Bukry, 1969, p. 51, pi. 28, fig ; pi. 29, fig. 1. Eiffellithus aff. E. eximius (Stover) Perch-Nielsen. Perch-Nielsen, 1972, p. 1008, pi. 22, fig. 4, 6.

89 Remarks: E. exlmlus has been differentiated from other species of the genus by its broad bars, which are almost parallel to the axes of the elliptical disc and show forked peripheral tips. The angle ~ is smaller than 20 (see also remarks on evolution). Slightly forked peripheral tips occur but rarely in the accompanying E. turriseiffeli. (see also addendum, p. 124). Composite range: Middle Turonian-Upper Campanian. Eiffellithus parallelus Perch-Nielsen (pi. 5, fig. 10) Remarks: E. parallelus can be recognized by its short and broad bars with irregular ends. Though no distinct transitional forms were found, it is most likely that E. turriseiffeli is the ancestral form of E. parallelus. Composite range: Lower Maastrichtian-Upper Maastrichtian. Eiffellithus turriseiffeli (Deflandre) Reinhardt (pi. 5, fig. 8-9) Zygolithus turriseiffeli Deflandre, in Deflandre and Fert, 1954, p. 149, pi. 13, fig. 1 textfig. 65. Zygrhablithus turriseiffeli (Deflandre) Deflandre, 1959, p Eiffellitus turriseiffeli turriseiffeli (Deflandre) Reinhardt, 1965, p. 36. Eiffellithus turriseiffeli (Deflandre) Reinhardt. Bukry, 1969, p. 52, pi. 29, fig Remarks: E. turriseiffeli developed from Vekshinella angusta (Stover) by rotation of the bars and the closing of the central area. The longest bar of E. turriseiffeli always makes an angle of more than 20 with the longer axis of the elliptical disc. The central area is never completely open (see remarks on evolution). Composite range: Upper Albian-Maastrichtian. Genus Helicolithus Noel 1970 Type species: Discolithus anceps Gorka 1957 Remarks: The genus includes those species with a margin composed of a larger number of elements, which imbricate clockwise and with an inner margin cycle of six large elements. The central structure is composed of four, short and broad bars sometimes supporting a central process. It differs from the genus Eiffellithus by the broad inner margin cycle and the open central area and from Chiastozygus by the broad inner margin cycle and the broader bars.

90 The genus Helicolithus contains species which have been assigned to Eiffellithus by different authors but which do not evolve from Vekshinella angusta (Stover). i.e. Helicolithus anceps (not found) and Helicolithus trabeculatus. Discolithus trabeculatus Gorka, 1957, p. 277, pi. 3, fig. 9. Discolithus disgregatus Stover, 1966, p. 142, pi. 2, fig ; pi. 8, fig. 12. Eiffellithus trabeculatus (Gorka) Reinhardt and Gorka, 1967, p. 250, pi. 31, fig. 19,23; pi. 32, fig. 1; Roth and Thierstein, 1972, pi. 12, fig Chiastozygus disgregatus (Stover) Bukry, 1969, p. 49, pi. 27, fig Remarks: H. trabeculatus differs from H. anceps by a larger central area and more distinct bars. It is placed in the genus Helicolithus because of its inner margin cycle of six long elements, excellently figured by Bukry (1969) and Roth and Thierstein (1972). Composite range: Middle Albian-Maastrichtian. Genus Parhabdolithus Deflandre, 1952 Type species: Parhabdolithus liasicus Deflandre, Remarks: The genus shows a very high and broad margin with a broad inner margin cycle, leaving a relatively small central area, in which a broad bar supports a large central process. The genus Zygodiscus Bramlette and Sullivan shows a less sturdy construction without an inner margin cycle or with a narrow one. Species with a closed central area, which have been incorporated by various authors in Parhabdolithus are assigned to the genus Rhagodiscus Reinhardt. Parhabdolithus embergeri (Noel) Stradner (pi. 5, fig ) Discolithus embergeri Noel, 1959, p. 164, pi. 1, fig. 5, 6a-e, 7a-b, 8 (Farinacci, Catalogue of calcareous nannofossils). Parhabdolithus embergeri (Noel) Stradner, 1963, p. 8, pi. 4, fig. 1; Bramlette and Bukry, 1969, pi. 3, fig. F;Manivit, 1971, p. 88, pi. 20, fig Microrhabdulinus ambiguus Deflandre, 1963, p. 3486, fig Zygodiscus? pseudanthoporus Bramlette and Martini, 1964, p. 303, pi. 3, fig. 17; pi. 4, fig Zygodiscus lacunatus Gartner, 1968, p. 33, pi. 17, fig. 6; pi. 18, fig ; pi. 19, ftg. 5; pi. 23, fig ; pi. 24, fig. 3; Bukry, 1969, p. 60, pi. 34, fig Zygodiscus pseudanthoporus Bramlette and Martini. Gartner, 1968, p. 33, pi. 2, fig ; pi. 3, fig. 14; pi. 13, fig Remarks: P. embergeri shows a rather strong variation in the width of the bar, which is always broader than the diameter of the perforations. The

91 specimens assigned to Microrhabdulinus ambiguus are considered to be broken off central processes of P. embergeri. Composite range: Lower Tithonian-Maastrichtian. Mitosia infinitae Worsley, 1971 p. 1311, pi. 1, fig Parhabdolithus infinitus (Worsley) Thierstein, in Roth and Thierstein, 1972, p. 437, pi. 9, fig Remarks: The proximal ridges subparallel to the longer axis of the disc are typical for this species, which was recorded only from samples of the type Albian. Composite range: Upper Hauterivian-Cenomanian. Genus Pontilithus Gartner, 1968 Type species: Pontilithus obliquicancellatus Gartner, 1968 Rem'arks: The genus is differentiated from the other genera of the family by the thin spokes in the central structure. Remarks: This species differs from Pontilithus complexus Bukry by the much thinner bar parallel to the shorter axis of the disc. Composite range: Cenomanian-Santonian. Genus Reinhardtites Perch-Nielsen, 1968 Type species: Rhabdolithus anthoporus Deflandre, Rem'arks: The slightly conical central structure with two perforations and a bar parallel to the shorter axis of the elliptical disc, and the broad proximal cycle are characteristic for this genus. Reinhardtites anthophorus (Deflandre) Perch-Nielsen (pi. 6, fig. 1-2) Rhabdolithus anthophorus Deflandre, 1959, p. 137, pi. 1, fig Cretarhabdus? anthophorus (Deflandre) Bramlette and Martini, 1964, p. 299, pi. 3, fig Discolithus cryptochondrus Stover, 1966, p. 142, pi. 2, fig. 8-9; pi. 8, fig. 13. Reinhardtites anthophorus (Deflandre) Perch-Nielsen, 1968, p. 38, pi. 5, fig. 1-8, textfig Amphizygus brooksii nanus Bukry, 1969, p. 47, pi. 25, fig Reinhardtites? anthophorus (Deflandre) Perch-Nielsen. Manivit, 1971, p. 89, pi. 20, fig. 9-10,

92 Remarks: R. anthophorus is characterized by its two small perforations and the slightly conical central structure. Specimens with rather large perforations have been placed in Reinhardtites brooksii (Bukry). In order to differentiate R. anthophorus (= Amphizygus brooksii nanus Bukry) from R. brooksii (= Amphizygus brooksii brooksii Bukry), the definitions of Bukry 1969 were followed. Composite range: Lower Campanian-Upper Maastrichtian. Reinhardtites brooksii (Bukry) n. comb. (pi. 6, fig. 3) Remarks: R. brooksii shows the same construction as R. anthophorus but it can be recognized by larger central perforations and a smaller number of elements in the margin. Comp9site range: Upper Turonian-Upper Campanian. Reinhardtites miniporus (Reinhardt and Gorka) n. comb. (pi. 6, fig. 4-5) Nephrolithus miniporus Reinhardt and Gorka, 1967, p. 246, pl. 32, fig. 11; pl. 33, fig. 5. Amphizygus minimus Bukry, 1969, p. 48, pi. 25, fig Reinhardtites minimus (Bukry) Reinhardt, 1971b, p. 21, textfig. 21. Remarks: This species is placed in the genus Reinhardtites, because its central structure is very similar to that of R. anth'ophorus. It differs from R. anthophorus in being smaller and in having a relatively broad proximal margin cycle. Composite range: Santonian-Maastrichtian. Genus Rhagodiscus Reinhardt, 1967 Type species: Discolithus asper Stradner, Remarks: This genus has a narrow margin and a central area closed by an imperforated and granulate plate generally with rather irregularly arranged ridges. In most of its species a central process extends from the midpoint of the central structure. Rhagodiscus differs from Parhabdolithus by its closed central area and from Eiffellithus by the lack of bars. The genus Rhabdolithina Reinhardt (1967) is considered to be a synonym, because the only difference originally described by Reinhardt (1967) is the absence of a central process in Rhagodiscus, but its type species generally does show such a central process.

93 Rhagodiseus angustus (Stradner) Reinhardt (pi. 6, fig. 6) Rhabdolithus angustus Stradner, 1963, p. 12, pi. 5, fig. 6. Parhabdolithus elongatus Stover, 1966, p. 144, pi. 6, fig ; pi. 9, fig. 18. Ahmuellerella angusta (Stradner) Reinhardt, 1966, p. 25, pi. 22, fig Rhabdolithina angusta (Stradner) Reinhardt, 1967, p. 168, pi. 7, fig Parhabdolithus angustus (Stradner) Stradner, Adamiker and Maresch, 1968, p. 32, pi. 20, fig Rhabdolithina extans Hoffman" 1970c, p. 187, pi. 3, fig. 5. Rhagodiscus angustus (Stradner) Reinhardt, 1971b, p. 23, textfig. 10. Remarks: Specimens from Campanian and Maastrichtian rocks often do not show a ridge, whereas older specimens always have a ridge parallel to the shorter axis of the disc. Composite range: Upper Aptian-Maastrichtian. Rhagodiscus asper (Stradner) Reinhardt (pi. 6, fig. 7, 8) Discolithus asper Stradner, 1963, p. 11, pi. 2, fig Discolithus vagus Stover, 1966, p. 144, pi. 3, fig ; pi. 8, fig. 20. Parhabdolithus granulatus Stover, 1966, p. 144, pi. 6, fig ; pi. 9, fig. 17. Rhagodiscus asper (Stradner) Reinhardt, 1967, p Parhabdolithus asper (Stradner) Manivit, 1971, p. 87, pi. 23, fig. 4-7; Roth and Thierstein, 1972, pi. 7, fig Remarks: The species is characterized by a broad oval to elliptical basal disc with a rather irregular pattern of ridges on the plate closing the central area. Specimens without ridges, such as figured by Roth and Thierstein (1972), were not observed. Composite range: Lower Berriasian-Turonian. Rhagodiscus reniformis Perch-Nielsen (pi. 6, fig. 10) Rhagodiscus reniformis Perch-Nielsen, 1973, p. 323, pi. 3, fig. 2,4,6; pi. 10, fig Nephrolithus frequens Gorka. Verbeek, 1976b, p. 145, pi. 3, fig. 6. Remarks: The specimens found show a more coarsely granulate central structure, than figured by Perch-Nielsen (1973). R. reniformis differs from the other species of the genus, because of the absence of ridges and a central structure, and from N. frequens by the absence of a thick proximal margin cycle. Composite range: Upper Santonian-Maastrichtian.

94 Rhagodiscus splendens (Deflandre) n. comb. (pi. 6, fig. 9) Rhabdolithus splendens Deflandere, 1953, p. 1785, fig. 4-6; Deflandre and Fert, 1954, p. 158, pi. 13, fig. 1-3, textfig Cretarhabdus splendens (Deflandre) Bramlette and Martini, 1964, p. 300, pi. 3, fig Rhabdolithinasplendens (Deflandre) Reinhardt, 1967, p.167. Actinozygus splendens (Deflandre) Gartner, 1968, partim, p. 25, pi. 5, fig ; pi. 7, fig. 1-2; pi. 11, fig. 15 non pi. 10, fig. l. Parhabdolithus splendens (Deflandre) Noel, 1969b, p. 476, pi. 1, fig. 1-4,7, textfig.1-2;roth and Thierstein, 1972, pi. 7, fig. 2-h. Remarks: The plate closing the central area and its radial ridges enable the differentiation of this species from P. asper. Composite range: Upper Valanginian-Maastrichtian. Genus Tegumentum Thierstein, 1972 Type species: Tegumentum stradneri Thierstein, Tegumentum stradneri Thierstein (pi. 7, fig. 1) Zygolithus litterarius (Gorka) Stradner, Adamiker and Maresch, 1968, partim, p. 39, pi. 34, fig. 1, 4-7, non pi. 34, fig. 23. Tegumentum stradneri Thierstein, in Roth and Thierstein, 1972, p. 437, pi. 1, fig Remarks: Only specimens were found in which the outer margin cycle is much narrower than figured by Roth and Thierstein (1972). These authors give a range up to the Maastrichtian, but in our material T. stradneri was only found in the Middle Albian of Monteramy, Villemoyenne and Courcelles. Composite range: Lower Barremian-Maastrichtian. Genus Tranolithus Stover, 1966 Type species: Tranolithus ma,jifestus Stover, 1966 (= Tranolithus orionatus (Reinhardt) Reinhardt, 1966 b). Remarks: This genus is differentiated from the genus Zygodiscus Bramlette and Sullivan by having two or four elements as a central structure, which do not form a bar. Tranolithus orionatus (Reinhardt) Reinhardt (pi. 7, fig. 2-4)

95 Tranolithus exiguus Stover, 1966, p. 146, pi. 4, fig ; pi. 9, fig. 3-4, Manivit, 1971, p. 85, pi. 26, fig ,18; Roth and Thierstein, 1972, pi. 10, fig Tranolithus gabalus Stover, 1966, p. 146, pi. 4, fig. 22; pi. 9, fig. 5; Roth and Thierstein, 1972, pi. 10, fig Tranolithus manifestus Stover, 1966, p. 146, pi. 4, fig ; pi. 9, fig. 6. Tranolithus phacelosus Stover, 1966, p. 146, pi. 4, fig ; pi. 9, fig. 7. Tranolithus orionatus (Reinhardt) Reinhardt, 1966b, p. 522; Manivit. 1971, p. 85, pi. 26, fig ; Roth and Thierstein, 1972, pi. 10, fig ; Thierstein, 1976, p. 352, pi. 1, fig. 7-8; pi. 4, fig Zygolithus exiguus (Stover) Manivit, 1968, p. 279, pi. 1, fig. 11. Zygolithus phacelosus (Stover) Manivit, 1968, p. 280, pi. 1, fig. 12. Zygodiscus? phacelosus (Stover) Bukry, 1969, p. 61, pi. 35, fig. 12. Zygostephanos orionatus (Reinhardt) Hoffman, 1970c, p. 178, pi. 1, fig. 5; pi. 3, fig. 3, textftg. 3, fig. 6. Remarks: All species listed in the list of synonyms have the same basic construction: a margin consisting of a distal margin cycle and a narrower proximal margin cycle, and a central structure composed of four elements, two at each of the longer sides of the margin. The shape of these elements depends on the amount of secondary calcite. They even may have become fused. Different types of overgrowth are figured by Roth and Thierstein (1972), by Thierstein (1976) and in this paper. Composite range: Upper Aptian-Maastrichtian. Genus Vekshinella Loeblich and Tappan, emend. Gartner, 1968 Type species: Ephippium acutiferrus Vekshina, Remarks: This genus is characterized by a margin consisting of two cycles of elements and a central structure composed of four bars forming a cross parallel to the axes of the elliptical disc; a central process may be present. Vekshina (1959) described the genus Ephippium as "stephanoliths with a central projection-spine". Loeblich and Tappan (1963) found the name preoccupied and changed it to Vekshinella. Gartner (1968) emended the generic diagnosis of Vekshina (1959) and described the margin as a single cycle with sometimes a rim, whereas Vekshina had described the margin as single layered without mentioning the number of cycles. In the figures given by Gartner of species belonging to the genus two cycles are visible; the figures by Vekshina are not clear enough to ascertain the number of cycles in the type species. For these reasons the margin is considered to be single layered, but composed of two cycles of elements. This concept of the margin of the genus Vekshinella leads to the conclusion, that the genus Vagalapilla is a junior synonym.

96 Vekshinella angusta (Stover) n. comb. (pi. 6, fig ) Remarks: This species is considered to be the ancestor of E. turriseiffeli (see remarks on evolution). The older forms from Middle Albian sediments show bars which are almost parallel to the axes of the oval disc (pi. 6, fig. 12). Younger forms from Upper Albian rocks have bars, which seem to have rotated slightly and a proximal cycle which extends sometimes into the central area (pi. 6, fig. 11). Because the bars are parallel to nearby parallel to the axes of the disc and the central area is completely or for the larger part open, this species is placed in the genus Vekshinella and not in the genus Eiffellithus, in which the central area is closed or almost closed, and the bars make larger angles with the axes of the disc. Composite range: Aptian-Upper Albian. Vekshinella bochotnicae (Gorka) n. comb. (pi. 7, fig. 5) Discolithus bochotnicae Gorka, 1957, p. 250, pi. 2, ftg. 15. Staurolithites bochotnicae (Gorka) Reinhardt, 1965, p. 39, pi. 3, ftg. 3; Manivit, 1971, p. 82, pi. 27, fig. 1-5, Vekshinella imbricata Gartner, 1968, p. 30, pi. 9, fig ;pL 13, ftg Remarks: This species has a margin composed of two cycles of elements and bars parallel to the axes of the elliptical disc and therefore it had been placed in the genus Vekshinella. V. bochotnicae is very similar to V. crux but much larger, more slender and it has a shorter stratigraphic range. Composite range: Middle Santonian-Maastrichtian. Vekshinella crux (Deflandre and F ert) Risatti (pi. 7, fig. 6) Discolithus crux Deflandre and Fert, 1954, p. 143, pi. 14, ftg. 4, textftg. 55. Staurolithites crux (Deflandre and Fert) Caratini, 1963, p. 25. Zygolithus crux (Deflandre and Fert) Bramlette and Sullivan, 1961, p. 149, pi. 6, fig Vekshinellastradneri Rood, Hay and Barnard, 1971, p. 249, pi. 1, ftg. 2. Vekshinella crux (Deflandre and Fert) Risatti, 1973, p. 19, pi. 7, fig Remarks: The width of the bars varies from rather thin to almost closing the central area. Sometimes a groove on the bars is visible. Specimens from Middle Albian sediments sometimes show a kind of foot at the base of the bars. Composite range: Upper Oxfordian-Maastrichtian.

97 Genus Zygodiscus Bramlette and Sullivan, emend Gartner, 1968 Type species: Zygodiscus adamas Bramlette and Sullivan, Remarks: This genus is easily recognizable by its bar parallel to the shorter axis of the elliptical disc. Zygodiscus acanthus (Reinhardt) (pi. 7, fig. 7) Reinhardt Zeugrhabdus acanthus Reinhardt, 1965, p. 37, pi. 3, fig. 1. Zygodiscus acanthus (Reinhardt) Reinhardt, 1966a, p. 40, pi. 15, fig. 5, pi. 23, fig. 8; Bukry, 1969, p. 58, pi. 33, fig. 8-9; non Manivit, 1971, p. 77, pi. 13, fig Remarks: Z. acanthus differs from Zygodiscus theta (Black) in having a distinct inner margin cycle, which is lacking in Z. theta. The specimens figured by Manivit (1971) have no such inner margin cycle. Composite range: Albian-Maastrichtian. Zygodiscus diplogrammus (Deflandre) Gartner (pi. 7, fig. 8) Zygolithus diplogrammus Deflandre, in Deflandre and Fert, 1954, p. 148, pi. 10, fig. 7, textfig. 57. Glaukolithus diplogrammus (Deflandre) Reinhardt, 1964, p Zygolithus ponticulus (Deflandre) Stover, 1966, p. 148, pi. 4, fig Zygolithus stenopous Stover, 1966, p. 148, pi. 4, fig. 6-9; pi. 8, fig. 25. Zygodiscus compactus Bukry, 1969, p. 59, pi. 34, fig Remarks: Strong variation has been observed in the width of the bar, which has a distinct groove and occasionally a central process. Composite range: Upper Valanginian-Maastrichtian. Zygodiscus elegans Gartner, emend. Bukry. (pi. 7, fig. 10) Zygodiscus elegans Gartner, 1968, p. 32, pi. 10, fig. 3-6; pi. 12, fig. 3-4; pi. 27, fig. 1; emend. Bukry, 1969, p. 59, pi. 34, fig Glaukolithus elegans (Gartner, emend. Bukry), Roth and Thierstein, 1972, pi. 10, fig ; Thierstein, 1973, p. 36, pi. 2, fig Zygodiscusfibuliformis (Reinhardt) Bukry, Verbeek, 1976a, p. 76, pi. 1, fig. 2. Remarks: This species differs from Zygodiscus spiralis Bramlette and Martini by a narrower proximal margin cycle, which does not extend into the central area. In the light microscope the corresponding spiral-shaped extinction pattern is less distinct, than in Z. spiralis. Composite range: Lower Berriasian-Campanian.

98 Zygodiscus minimus Bukry (pi. 7, fig. 9) Zygodiscus minimus Bukry, 1969, p. 61, pi. 35, fig Zygolithus tarboulensis Shafik and Stradner. Perch-Nielsen, 1973, pi. 10, fig Remarks: The two plates closing the openings on either side of the thin bar enable the differentiation of this species from other species of the genus Zygodiscus. The two plates show strong birefringence in cross-polarized light. The bar, which supports a spine, is generally broken off. Composite range: Upper Albian-Maastrichtian. Remarks: Composite This Paleocene species is characterized by a sigmoid bar. range: Danian-Thanetian. Zygodiscus spiralis Bramlette and Martini (pi. 7, fig ) Zygodiscus spiralis Bramlette and Martini, 1964, p. 303, pi. 4, fig. 6-8; Gartner, 1968, p. 35, pi. 5, fig ; pi. 7, fig. 3; Perch-Nielsen, 1968, p. 89, pi. 27, fig. 7-13; Manivit, 1971, p. 80, pi. 29, fig ; Roth, 1973, p. 727, pi. 20, fig. 5; Verbeek, 1976b, pi. 2, fig. 5. Zygodiscus ponticulus non (Deflandre) Manivit, Aberg, 1968, p. 7, pi. 2, fig Zygodiscus fibuliformis (Reinhardt) Bukry, 1969, p. 59, pi. 34, fig. 9-10; non Verbeek, 1976a, p. 76, pi. 1, fig. 2. Placozygus fibuliformis (Reinhardt) Hoffmann, 1970b, p. 1004, pi. 1, fig. 1-4, textfig. la-b. Placozygus spiralis (Bramlette and Martini) Hoffmann, 1970b, p. 1007, pi. 1, fig. 6, textfig. 1d. Remarks: Z. spiralis is recognized by its broad proximal margin cycle, which slopes into the central area. In the light microscope this species has a characteristic spiral-shaped extinction pattern. Composite range: Middle Santonian-Maastrichtian. Zygodiscus theta (Black) Bukry (pi. 8, fig. 1) Discolithus theta Black, in Black and Barnes, 1959, p. 327, pi. 12, fig. 1. Zygodiscus theta (Black) Bukry, 1969, p. 62, pi. 36, fig Discolithina theta (Black) Forchheimer, 1970, partim, p. 25, textfig ,32-33,44 non fig. 31. Remarks: This species is characterized by a narrow bar with broad ends. Composite range: Cenomanian-Campanian.

99 Family MICRORHABDULACEAE Deflandre, 1963 Remarks: All rod-shaped nannofossils without a distinct basal disc are assigned to this family. Genus Lithraphidites Deflandre, 1963 Type species: Lithraphidites carniolensis Deflandre, 1963 Remarks: The rods are composed of four blades forming together a subquadrate petaloid pattern in cross-section; the rods show tapering ends. The genus Lithraphidites is characterized by these blades, whereas Microrhabdulus Deflandre consists of rods without blades, being sub circular in cross-section. Lithraphidites acutum Verbeek and Manivit (pi. 8, fig. 3) Lithraphidites alatus non Thierstein, Thierstein, 1974, p. 641, pi. 3, fig. 5-11; Verbeek, 1976a, p. 77, pi. 2, fig. 5. Lithraphidites acutum Verbeek and Manivit, in Manivit et ai., 1977, p. 176, pi. 1, fig Remarks: This species has a long prominent peak near the center of each blade. Composite range: Cenomanian-Turonian. Lithraphidites alatus Thierstein (pi. 8, fig. 2) Remarks: This species is characterized by the gradual increase of width of the blades from one end to a point close to the other end. Beyond the latter point a sudden decrease in width was observed in some specimens. Composite range: Upper Albian-Cenomanian. Lithraphidites carniolensis Deflandre (pi. 8, fig. 4) Lithraphidites camiolensis Deflandre, 1963, p. 3486, textfig. 1-10; Stradner, Adamiker and Maresch, 1968, p. 45, pi. 47, fig. 1-5; Bukry, 1969, p. 66, pi. 39, fig. 1-2; Manivit, 1971, p. 130, pi. 16, fig Lithraphidites cf. L. quadratus Bramlette and Martini, Verbeek, 1976b, p. 145, pi. 3, fig. 4. Remarks: This species differs from all other species of the genus by its great length and narrow blades without ornamentation. Composite range: Lower Berriasian-Maastrichtian.

100 Lithraphidites quadratus Bramlette and Martini (pi. 8, fig. 5) Lithraphidites quadratus Bramlette and Martini, 1964, p. 310, pi. 6, fig. 16~17; pi. 7, fig. 8; Manivit, 1971, p. 130, pi. 16, fig. 11; Verbeek, 1976b, pi. 3, fig. 2. Remarks: The short and broad blades with concave ends and parallel sides differentiate this species from all other species of the genus. Composite range: Maastrichtian. Genus Microrhabdulus Deflandre, 1959 Type species: Microrhabdulus decoratus Deflandre, 1959 Remarks: This genus includes all rod-shaped coccoliths with oval to circular cross-section. Microrhabdulus belgicus Hay and Towe (pi. 8, fig. 6) Microrhabdulus belgicus Hay and Towe, 1963, p. 95, pi. 1; Bukry, 1969, p. 66, pi. 39, fig Microrhabdulus margaritus Deflandre, 1963, p. 3486, textfig Microrhabdulus nodosus Stradner, 1963, p. 11, pi. 4, fig. 13. Remarks: The small blocky elements on the surface of the rod are typical for this species. Composite range: Cenomanian-Maastrichtian. Microrhabdulus decoratus Deflandre (pi. 8, fig. 7) Microrhabdulus decoratus Deflandre, 1959, p. 140, pi. 4, fig. 1-5; Bramlette and Martini, 1964, p. 314, pi. 6, fig Microrhabdulus stradneri Bramlette and Martini, 1964, p. 316, pi. 6, fig. 3-6; Gartner, 1968, p. 44, pi Remarks: M. decoratus and M. stradneri are considered conspecific, because most of our specimens are intermediate forms. In cross-polarized light, it depends on the orientation whether the extinction pattern consists of triangles or rectangles, which configurations have been described by Bramlette and Martini (1964) to give the most important difference between both species. In the SEM both species show the same construction of long, parallel elements. Composite range: Cenomanian-Maastrichtian.

101 Microrhabdulus? sp. Bramlette and Martini, 1964, p. 316, pi. 6, fig. 5. Microrhabdulus? elongatus Gartner, 1968, p. 44, pi. 9, fig. 21, pi. 12, fig. 15. Remarks: The basal disc described by Bramlette and Martini (1964) and by Gartner (1968) was not observed during this study. Composite range: Middle and Upper Maastrichtian. Family PODORHABDACEAE Noel, 1965 Remarks: In this family all genera have been included in which the basal disc consists of two, or sometimes three, shields and the central structure is composed of bars or a perforated plate commonly supporting a central process. Genus Cretarhabdus Bramlette and Martini, 1964 Type species: Cretarhabdus conicus Bramlette and Martini, Remarks: The species of this genus have margins constructed of two or three shields and a central structure, which is divided in four quadrants by bars parallel with the axes of the elliptical basal disc. The quadrants show various ornamentation types. Sometimes the bars are poorly developed. Cretarhabdus conicus Bramlette and Martini, 1964, p. 299, pi. 3, fig. 5-8; Bukry, 1969, p. 35, pi. 13, fig. 7-12; Thierstein, p. 477, pi. 6, fig. 7-12; Black, 1973, p. 49, pi. 17, fig. 1-2, 15. Cretarhabdella lateralis Black. Black, 1972, p. 46, pi. 14, fig Cretarhabdella spectabilis Black, 1972, p. 47, pi. 16, fig Cretarhabdus barremianus Black. Black, 1973, p. 50, pi. 18, fig Cretarhabdus sp. C. primus Black. Black, 1973, p. 56, pi. 17, fig Remarks: C. conicus is recognized by its two or three cycles of perforations in the central structure. Especially in specimens from Campanian and Maastrichtian sediments the central structure is high conical. Composite range: Lower Berriasian-Maastrichtian. Cretarhabdus crenulatus Bramlette and Martini, 1964, p. 300, pi. 2, fig ; emend. Thierstein, 1971, p. 476, pi. 5, fig Cretarhabdus crenulatus crenulatus (Bramlette and Martini) Bukry, 1969, p. 35, pi. 14, fig. 1-6, 12. Remarks: Characteristic for this species are the eight bars of the central structure. Those parallel to the axes of the elliptical disc are sometimes stronger than the others. Composite range: Upper Berriasian-Maastrichtian.

102 Cretarhabdus loriei Gartner (pi. 8, fig. 8) Arkhangelskiella striata Stradner. Stover, 1966, p. 137, pi. 2. fig Cretarhabdus loriei Gartner, 1968, p. 21, pi. 24, fig. 9-10; Bukry, 1969, p. 36, pi. 15, fig. 1~3; Thierstein, 1973, p. 40, pi. 4, fig Polypodorhabdus hansmanni (Bukry) Black, 1972, p. 42, pi. 10, fig. 5. Cretarhabdus glomarus Burns, 1976, p. 285, pi. 3, fig. 3. Remarks: C. loriei is distinguishable by the sets of thin parallel bars in the quadrants of the central structure. These quadrants are formed by the broader bars parallel to the axes of the basal disc. The thin bars are sometimes connected by crystals. Composite range: Upper Aptian-Campanian. Vekshinellaschizobrachiata Gartner, 1968, p. 31, p. 13, fig ; pi. 20, fig. 5. Cretarhabdus schizobrachiatus (Gartner) Bukry, 1969, p. 36, pi. 15, fig. 4-16; Manivit, 1971, p. 97, pi. 7, fig Polypodorhabdus schizobrachiatus (Gartner) Shafik and Stradner, 1973, p. 87, pi. 15, fig Retecapsa levis Black, Black, 1972, p. 40, pi. 10, fig Remarks: This species may be differentiated from c. crenulatus and Cretarhabdus surirellus (Deflandre) by the presence of short bars in the angles between the margin and the bars parallel to the axes of the basal disc and by the absence of other radial bars. Composite range: Middle Barremian-Maastrichtian. Cretarhabdus surirellus (Deflandre) Reinhardt (pi. 8, fig. 9) Discolithus surirella Deflandre, in Deflandre and Fert, 1954, p. 144, textfig Tremalithus romani Gorka, 1957, p. 271, pi. 2, fig. 5. Coccolithus actinosus Stover, 1966, p. 138, pi , pi. 8, fig. 7. Cretarhabdus crenulatus hansmanni Bukry, 1969, p. 35, pi. 14, fig. 7~9. Cretarhabdus surirellus (Deflandre and Fert) Reinhardt, 1970b, partim, p. 50, pi. 1, fig. 8; pi. 2, fig. 1-6, textfig. 22 non pi. 1, fig. 6-7; Thierstein, 1971, p. 477, pi. 6, fig Cretarhabdus actinosus (Stover) Forchheimer, 1972, p. 49, pi. 19, fig. 4; Black, 1973, p. 49, pi. 18, fig Cretarhabdus biseriatus Forchheimer, Black, 1973, p. 50, pi. 17, fig Cretarhabdus cantaniatus Black, 1973, p. 51, pi. 18, fig Cretarhabdus leporarii Black, 1973, p. 52, pi. 18, fig Remarks: This species is characterized by more than eight radial bars, which support a plate with a central process. Composite range: Lower Berriasian-Maastrichtian.

103 Genus Cribrocorona Perch-Nielsen, 1973 Type species: Coccolithus gallicus Stradner, Remarks: Because the central structure of Cribrocorona is so similar to that of Cribrosphaerella Deflandre it may be concluded that both genera are closely related (Perch-Nielsen, 1973). If Cribrosphaerella is to be placed in the Podorhabdaceae (Thierstein, 1973) also Cribrocorona belongs to this family. It is different from the other genera of this family by its cylindrical shape. Cribrocorona gallica (Stradner) Perch-Nielsen (pi. 8. fig ) Coccolithus gallicus Stradner, 1963, p. 10, pi. 1, fig. 8-8a. Cylindralithus? gallicus (Stradner) Bramlette and Martini, 1964, p. 308, pi. 5, fig Cribrocoronagallica (Stradner) Perch-Nielsen, 1973, p. 312, pi. 4, fig Remarks: The grillate structure in the center of the cylinder excludes the possibility to place this species in the genus Cylindralithus Bramlette and Martini. Composite range: Middle Campanian-Maastrichtian. Genus Cribrosphaerella Deflandre, 1952 Type species: Cribrosphaera ehrenbergi Arkhangelsky, 1912 Remarks: Because of the similarity between the margins of the genera Cribrosphaerella and Cretarhabdus, Cribrosphaerella is placed in the family Podorhabdaceae, though bars and a central process are absent. Cribrosphaerella circula (Risatti) n. comb. (pi. 9, fig. 3-4) Cribrosphaera ehrenbergi Arkhangelsky,Bukry, 1969, partim, p. 44, pi. 22, fig. 12 non pi. 22, fig Cribrosphaera laughtoni (Black) Bukry, 1969, partim, p. 45, pi. 23, fig. 6 non pi. 23, fig. 1-5,7-9. Cribrosphaera circula Risatti, 1973, p. 24, pi. 8, fig Remarks: This species has to be placed in the genus Cribrosphaerella, because the name Cribrosphaera is invalid, being preoccupied according to Deflandre (1952). Composite range: Upper Santonian-Maastrichtian.

104 Cribrosphaerella ehrenbergii (Arkhangelsky) Deflandre (pi. 9, fig. 1) Crisbrosphaera ehrenbergi Arkhange1sky, 1912, p. 142, pi. 6, fig (after Thierstein, 1973); Manivit, 1971, partim, p. 101, pi. 8, fig. 1-5,9-12 non pi. 8, fig. 6-8, 13. Cribrosphaerella ehrenbergii (Arkhangelsky) Deflandre, 1952, p. 111, textfig. 54a-b; Gartner, 1968, p. 40, pi. 1, fjg ; pi. 3, fig. 2; pi. 6, fig. 7; pi. 12, fjg. 2; pi. 15, fjg. 11; Bukry, 1969, partim, p. 44, pi. 22, fig non pi. 22, fjg. 7-8, 12. Favocentrum laughtoni Black, 1964, p. 313, pi. 53, fig Favocentrum mattewshi Black, 1964, p. 314, pi. 53, fig Discolithina cf. D. numerosa (Gorka) Bramlette and Martini, 1964, p. 301, pi. 1, fjg Cretadiscus colatus Gartner, 1968, p. 36, pi. 10, fig. 7-8; pi. 12, fig. 5; pi. 19, fig. 10. Cretadiscus polyporus Gartner, 1968, p. 36, pi. 1, fig ; pi. 4, fig. 13; pi. 25, fig. 5. Cribrosphaerella linea Gartner, 1968, partim, p. 40, pi. 1, fig. 16 non pi. 3, fig. 4; pi. 11, fig. 16. Cribrosphaera laughtoni (Black) Bukry, 1969, partim, p. 45, pi. 23, fig. 4-5, 7-9 non pi. 23, fjg. 1-3,6. Remarks: In this study all specimens of Cribrosphaerella with a margin of two or three shields, of which the two distal ones are closely appressed, and with a central structure consisting of a plate with more than two cycles of perforations, are assigned to G. ehrenbergii. This species was only found in sediments younger than Lower Santonian, though Thierstein (1973) reports a range starting in the Upper Albian. Composite range: Upper Albian-Maastrichtian. Cribrosphaerella pelta Gartner (pi. 9, fig. 2) Cribrosphaerella linea Gartner, 1968, partim, p. 40, pi. 3, fjg. 4; pi. 11, fig. 16 non pi. 1, fig. 16. Cribrosphaerellapelta Gartner, 1968, p. 41, pi. 10, fig Cribrosphaerella sp. Gartner, 1968 partim, p. 41, pi. 4, fig. 17; pi. 20, fjg. 7 non pi. 14, fig. 10. Cribrosphaera ehrenbergii Arkhangelsky, Bukry, 1969, partim, p. 44, pi. 22, fjg non pi. 22, fig. 7-8, 12; Manivit, 1971, partim, p.101, pi. 8, fig. 6-8, 13 non pi. 8, fig. 1-5,9-12. Cribrosphaera laughtoni (Black) Bukry, 1969, partim, p. 45, pi. 23, fjg. 4-5, 7-9 non pl. 23, fig. 1-3,6. Cribrosphaerapelta (Gartner) Bukry, 1969, p. 45, pi. 23, fig Cribrosphaerella ehrenbergi (Arkhangelsky) Deflandre, Perch-Nielsen, 1973, pi. 4, fjg Remarks: A small central structure with more than two cycles of perforations is characteristic for this species. The margin is constructed of two or three shields, of which the two distal ones may be closely appressed. c. pelta may be differentiated in the light microscope by its small central area. Composite range: Albian-Maastrichtian. Genus Cruciellipsis Thierstein, 1971 Type species: Coccolithus cuvillieri Manivit, 1966.

105 Remarks: Cruciellipsis is different from the genus Prediscosphaera Vekshina by its smaller central area and greater number of elements in the margin, and from Podorhabdus Noel by the absence of a second cycle in the distal shield of the margin. Cruciellipsis chiasta (Worsley) Thierstein (pi. 9, fig. 5) Helenea chiasta Worsley, 1971, p. 1310, pi. 1, fig Cruciellipsis chiasta (Worsley) Thierstein, in Roth and Thierstein, 1972, p. 437, pi. 6, fig Remarks: This species differs from Cruciellipsis cuvillieri (Manivit) by the four large wedge-shaped elements at the intersection of the bars, which bars are composed of one row of elements. The specimens figured by Roth and Thierstein (1972) show a smaller central area than those found in our material. Composite range: Lower Berriasian-Cenomanian. Cruciellipsis cuvillieri (Manivit) Thierstein (pi. 9, fig. 6) Coccolithus cuvillieri Manivit, 1966, p. 268, textflg. 2-3; Worsley, 1971, pi. 2, fig ? Cruciplacolithus sp. Bukry and Bramlette, 1969, p..374, pi. 3, fig. C-D; pi. 5, fig. C. Cruciellipsis cuvillieri (Manivit) Thierstein, 1971, p. 478, pi. 5, fig Remarks: C. cuvillieri shows a central process composed of more than four elements and bars constructed of more than one row of elements. Composite range: Lower Berriasian-Cenomanian. Genus Flabellites Thierstein, 1973 Type species: Flabellites biforaminis Thierstein, Remarks: The asymmetric distal shield of the margin and the small central area spanned by bars, which form an X-shaped pattern, differentiate Flabellites from all other genera of the family Podorhabdaceae. The genus is monospecific.

106 Genus Gaarderella Black, 1973 Type species: Gaarderellagranulifera Black, Remarks: Only one species of this genus is known and of this species only the proximal side. Black (1973) placed the genus in the family Sollasitaceae, a name considered to be a junior synonym of the Coccolithaceae. The proximal shield of the margin is constructed of more than one cycle, a feature unknown from the Cretaceous species of the Coccolithaceae, but present in some species assigned to genera of the Podorhabdaceae (see Bukry, 1969, pi. 14, fig. 9; pi. 16, fig. 15, 8-9) Therefore Gaarderella is placed in the Podorhabdaceae. Gaarderella granulifera Black (pi. 9, fig. 7-8) Remarks: One specimen was found (sample Fr 1142, Aube, France). It is not clear whether the ridge surrounding the central area is an inner margin cycle or a narrow third shield. The two cycles in the proximal shield as figured by Black (1973) could not be observed, probably due to overgrowth with secondary calcite. Composite range: Middle and Upper Albian. Genus Octopodorhabdus Noel, 1965 Type species: Octopodorhabdus praevisus Noel, Remarks: The central structure composed of a plate with eight perforations is characteristic for the genus. Octopodorhabdus decussatus (Manivit) Manivit Discolithus decussatus Manivit, 1961, p. 344, pi. 1, ftg. 7 (Loeblich and Tappan, 1966). Octopodorhabdus decussatus (Manivit) Manivit, 1971, p. 98, pi. 4, ftg Octocyclus magnus Black, 1972, p. 38, pi. 8, ftg. 1-5; pi. 9, fig Remarks: O. decussatus has eight oval to circular perforations, whereas O. preavisus Noel shows eight bars leaving eight triangular perforations in Noel's drawing (1965). Composite range: Albian-Santonian. Genus Podorhabdus Noel, 1965 Type species: Podorhabdus grassei Noel, Remarks: The genus Podorhabdus is distinguished by a second cycle of ele-

107 ments in the distal shield of the margin and a central structure consisting of a generally convex plate with four large perforations. Noel (1965) described a central structure with bars and did not describe the second cycle in the distal shield of the margin, but in her figured specimens belonging to the genus both features are clear, except that of pi. 7, fig. 2, which shows a coccolith, which probably has to be assigned to the genus Vekshinella Loeblich and Tappan. Podorhabdus coronadventis (Reinhardt) Reinhardt (pi. 9, fig. 10) Cretarhabdus coronadventis Reinhardt, 1966a, p. 26, pi. 23, fig ; Roth and Thierstein, 1972, pi. 5, fig Cretarhabdus unicorus Stover, 1966, p. 140, pi. 5, fig ; pi. 9, fig. 15; Bukry, 1969, p. 36, pi. 15, fig. 7-9; Porchheirner, 1972, p. 52, pi. 20, fig Podorhabdus coronadventis (Reinhardt) Reinhardt, 1970b, p. 86. Remarks: Both P. coronadventis and Podorhabdus decorus (Deflandre) have bars, which are not parallel to the axes of the disc, but P. coronadventis has a less distinct second cycle of elements in the distal shield than P. decorus. Composite range: Middle Albian-Campanian. Podorhabdus decorus (Deflandre) Thierstein (pi. 9, fig. 11) Rhabdolithus decorus Deflandre, in Deflandre and Pert, 1954, p. 159, pi. 13, fig. 4-6, textfig. 87. Cretarhabdus decorus (Deflandre) Bramlette and Martini, 1964, p. 300, pi. 3, fig Ahmuellerella? granulata Reinhardt, 1965, p. 39, pi. 1, fig. 4. Podorhabdusgranulatus (Reinhardt) Bukry, 1969, p. 37, pi. 16, fig Podorhabdus decorus (Deflandre) Thierstein, in Roth and Thierstein, 1972, p. 437, pi. 4, fig. 7-8, Tetrapodorhabdus coptensis Black, Black, 1972, p. 39, pi. 9, fig Remarks: This species is characterized by bars, which are not parallel to the axes of the basal disc, and a margin, of which the distal shield consists of two cycles of elements. Composite range: Lower Aptian-Maastrichtian. Podorhabdus dietzmannii (Reinhardt) Reinhardt (pi. 9, fig. 12) Ahmuellerella dietzmanni Reinhardt, 1965, p. 30, pi. 1, fig. 1, textfig. 1. Podorhabdus dietzmanni (Reinhardt) Reinhardt, 1967, p. 169, textfig. 4; Thierstein, 1971, p. 478, pi. 8, fig. 1-8; Thierstein, 1973, p. 39, pi. 3, fig. 20. Prediscosphaera? orbiculofenestra Gartner, 1968, p. 21, pi. 25, fig ; pi. 26, fig. 8. Podorhabdus orbiculofenestrus (Gartner) Thierstein, 1971, p. 478, pi. 8, fig. 9-17; Roth and Thierstein, 1972, pi. 6, fig. 1-7.

108 Remarks: This species has bars, which are parallel to the axes of the basal disc. Of all the differences described by Thierstein (1971) between P. dietzmannii and P. orbiculofenestrus. the difference in extinction pattern of the bars is the only feature visible in well-preserved specimens under the light microscope. A distinction between both species thus seems possible, but the difference is considered too small to recognize two species. Futhermore the specimens that could possibly be assigned to the P. orbiculofenestrus-type are very rare. Composite range: Upper Valanginian-eampanian. Genus Prediscosphaera Vekshina, 1959 Type species: Prediscosphaera decorata Vekshina, 1959 (= Prediscosphaera cretacea (Arkhangelsky, 1912) Gartner, 1968). Remarks: The sixteen wedge-shaped, non-imbricate elements of the distal shield of the margin are typical for this genus. Prediscosphaera columnata (Stover) Manivit (pi. 9, fig. 9) Deflandrius columnatus Stover, 1966, p. 141, pi. 6, fig. 6-10; pi. 9, fig. 16. Deflandrius cantabrigensis Black, 1967, p. 140, textfig. 1. Prediscosphaera columnata (Stover) Bukry and Bramlette, 1969, p. 372, pi. 2, fig. E (invalid, ICBN art. 32). Prediscosphaera columnata (Stover) Manivit, 1971, p. 100, pi. 21, fig ; Manivit et ai., 1977, p. 177, pi. 1, fig Remarks: This species differs from Prediscosphaera cretacea (Arkhangelsky) by its very small and circular basal disc. Composite range: Middle Albian-Upper Cenomanian. Prediscosphaera cretacea (Arkhangelsky) Gartner (pi. 10, fig. 1-2) Coccolithophora cretacea Arkhangelsky, 1912, p. 410, pi. 6, fig. 12-?13 (after Gartner, 1968). Prediscosphaera cretacea (Arkhangelsky) Gartner, 1968, p. 21, pi. 2, fig , etc.; Manivit, 1971, p. 99, pi. 22, fig. 1-14; Perch-Nielsen, 1973, pi. 7, fig. 3, 5. Prediscosphaera cretacea cretacea (Arkhangelsky) Gartner, Bukry, 1969, p. 38, pi. 16, fig. 12; pi. 17, fig. 1-6;Roth and Thierstein, 1972, pi. 16, fig. 5. Prediscosphaera cretacea lata Bukry, 1969, p. 39, pi. 17, fig Prediscosphaera cretacea ponticula Bukry, 1969, p. 39, pi. 17, fig ; Roth and Thierstein, 1972, pi. 16, fig Deflandrius catinus Shumenko, 1969, p. 153, pi. 2, fig Deflandrius cantabrigensis Black, Forchheimer, 1970, p. 37, fig Prediscosphaera majungae Perch-Nielsen, 1973, p. 321, pi. 8, fig. 1-6; pi. 10, fig

109 Remarks: This species shows a very strong variation in size, but the distal shield of the margin always contains sixteen elements, the basal disc has an oval to circular outline and contains an inner margin cycle, the bars are always radial, the central process has always the same typically twisted structure and wings at the top. All coccoliths with these features are included in this species. The largest variation is found in assemblages from Campanian and Maastrichtian sediments. The oldest specimens are rather small. Composite range: Middle Cenomanian-Maastrichtian. Prediscosphaera spinosa (Bramlette and Martini) Gartner Deflandrius spinosus Bramlette and Martini, 1964, p. 301, pi. 2, fig Eiffellithus cretaceous cretaceous Reinhardt, 1965, p. 35, pi. 2, fig. 4, textflg. 4. Discolithus incohatus Stover, 1966, p. 143, pi. 2, fig ; pi. 8, fig. 17. Prediscosphaera spinosa (Bramlette and Martini) Gartner, 1968, p. 20, pi. 2, fig ; pi. 3, fig. 9-10; pi. 5, fig. 7-9; pi. 6, fig. 16; pi. 11, fig. 17. Deflandrius cf.d. stoveri Perch-Nielsen, Forchheimer, 1972, p. 46, pi. 6, fig Remarks: This species differs from P. cretacea in having bars parallel to the axes of the elliptical basal disc, and from Prediscosphaera quadripunctatus (Gorka) by the larger central area. The central process is not twisted. Composite range: Middle Albian-Maastrichtian. Prediscosphaera quadripunctata (Gorka) n. comb. (pi. 10, fig. 3) Tremalithus quadripunctatus Gorka, 1957, p. 246, pi. 1, fig. 14. Deflandrius quadripunctatus (Gorka) Reinhardt and Gorka, 1967, p. 252, pi. 31, fig. 21, 25; pi. 33, fig. 3. Deflandrius stoveri Perch-Nielsen, 1968, p. 66, pi. 16, fig Prediscosphaera honjoi Bukry, 1969, p. 39, pi. 18, fig Remarks: This species is placed in the genus Prediscosphaera because of its. sixteen wedge-shaped elements in the distal shield of the margin. It is characterized by a small central area spanned by four bars parallel to the axes of the elliptical basal disc, and by a relatively broad margin. Composite range: Santonian-Maastrichtian. Family STEPHANOLITHIONACEAE Black, 1968 Remarks: This family includes all coccoliths with either a high or a low margin of variable shape, generally composed of a distal and a proximal margin cycle, and with a central area, which may be open, spanned by bars or closed by a plate.

110 Genus Corollithion Stradner, 1961 Type species: Corollithion exiguum Stradner, Remarks: The genus Corollithion includes hexagonal to circular coccoliths with a central structure composed of more or less radial bars sometimes supporting a little knob. The margin is usually rather thin. Chiphragmalithus achylosum Stover, 1966, p. 137, pi. 6, fig. 26;pl. 7, fig. 1-3; pi. 9, fig. 20. Corollithion achylosum (Stover) Thierstein, 1971, p. 480, pi. 8, fig Remarks: The circular outline and four bars make this species different from all other species of the genus. Composite range: Upper Aptian-Campanian. Corollithion? completum Perch-Nielsen (pi. 10, fig. 4) Remarks: The hexagonal margin of this species resembles that of the other species of the genus Corollithion, but because of the closed central area its placing in this genus is considered doubtful. Perch-Nielsen (1973) reported this species from Maastrichtian sediments of Madagascar and in our material it was found in the Cenomanian rocks of the Kef section. Composite range: Cenomanian-Maastrichtian. Corollithion exiguum Stradner, 1961, p. 83, textfig ; Stradner, 1963, pi. 1, fig. 12; Bramlette and Martini, 1964, p. 308, pi. 5, fig. 8-9; Reinhardt, 1966a, pi. 19, fig. 5; Gartner, 1968, p. 35, pi. 10, fig. 26; Bukry, 1969, p. 40, pi. 18, fig. 12; pi. 19, fig. 1; Manivit, 1971, p. 109, pi. 5, fig, 1-3; Risatti, 1973, p. 23, pi. 1, fig. 4-5; Verbeek, 1976a, p. 75, pi. 1, fig. 4. Stephanolithion sp. Stephanolithion laffitei Noel. Gartner, 1968, p. 35, pi. 5, fig. 14; pi. 22, fig. 18. Remarks: This species has six bars running from the centre of the coccolith to the middle of the ribs of the hexagonal margin, whereas Corollithion ellipticum Bukry shows a more elliptical outline with a central structure of six bars, which connect the centre with the middle of the long sides. Corollithion rhombicum (Stradner and Adamiker) has a smaller number of bars and Corollithion signum Stradner a larger number. As stated by Verbeek (1976a) C. exiguum appears in the Middle Cenomanian, but it is too rare to have any value as a zonal marker. Composite range: Middle Cenomanian-Maastrichtian.

111 Corollithion signum Stradner, 1963, p. 11, pi. 1, fig. 13; Bukry, 1969, p. 41, pi. 19, fig. 5-8; Manivit, 1971, partim, p. 110, pi. 5, fig. 6 non pi. 5, fig. 7-10; Thierstein, 1971, p. 480, pi. 8, fig Remarks: This species is distinguishable from all other species of this genus by a square to hexagonal outline and a central structure composed of four bars. Composite range: Upper Albian-Campanian. Genus Cylindralithus Bramlette and Martini, 1964 Type species: Cylindralithus serratus Bramlette and Martini, Remarks: In this genus the central structure may have different constructions or it is missing. The elements of the margin do not separate at their ends, contrary to the elements in the genus Lithastrinus Stradner. The margin is flaring at both sides or at one end. The elements of the proximal margin cycle have a sideward extension. Remarks: This species is very similar to Cylindralithus coronatus Bukry, but it has curved bars and C. coronatus has straight bars. Composite range: Upper Cenomanian-Maastrichtian. Cylindralithus serratus Bramlette and Martini (pi. 10, fig. 5-8) Cylindralithus serratus Bramlette and Martini, 1964, p. 309, pi. 5, fig ; Gartner, 1968, p. 47, pi. 10, fig. 9; Bukry, 1969, p. 43, pi. 20, fig ; Manivit, 1971, p. 111, pi. 10, fig ; Perch-Nielsen, 1973, pi. 5, fig. 2, 4, 6. Cylindralithus crassus Stover, 1966, p. 141, pi. 4, fig ; pi. 9, fig Remarks: This species is distinguishable from all other species of this genus by the lack of a central structure. The circular margin is more or less flaring at the distal side and shows a sideward extending cycle at the proximal side. Composite range: Turonian-Maastrichtian. Genus Lithastrinus Stradner, 1962 Type species: Lithastrinus grilli Stradner, Remarks: Cylindralithic coccoliths with concave sides composed of long elements, which are separated at the outer ends, and which have little rays towards the middle forming a shield in the center.

112 Lithastrinus floralis Stradner (pi. 10, fig. 10) Lithastrinus floralis Stradner, 1962, p. 370, fig. 6-11; Stradner, 1963, pi. 2, fig. 8-8a; Gartner, 1968, p. 47, pi. 21, fig. 13; pi. 22, fig ; pi. 24, fig. 12; Bukry, 1969, p. 43, pi. 21, fig. 1-2; Manivit, 1971, p. 139, pi. 15, fig. 3, 7-11, 15-16; Thierstein, 1971, p. 481, pi. 7, fig Eprolithus floralis (Stradner) Stover, 1966, p. 149, pi. 7, fig. 4-7; pi. 9, fig. 21. Lithastrinus moratus Stover, 1966, p. 149, pi. 7, fig. 20. Remarks: L. floralis is differentiated from Lithastrinus grilli Stradner by having symmetrical proximal and distal sides. The eleme~ts of the margin show obtuse ends, which are not elongated. In L. grilli these ends are acute and elongated, and the proximal and distal sides are often not symmetrical. Composite range: Upper Aptian-Campanian. Lithastrinus grilli Stradner (pi. 10, fig. 9) Lithastrinus grilli Stradner, 1962, p. 370, pi. 2, fig. 1-5; Stradner, 1963, pi. 2, fig. 9-9a; Gartner, 1968, partim, p. 47, pi. 18, fig. 1-2; pi. 20, fig. 17; pi. 21, fig. 1,11; pi. 22, fig. 26 non pi. 25, fig ; Bukry, 1969, p. 43, pi. 21, fig. 3-6; Roth and Thierstein, 1972, pi. 16, fig Remarks: L. grilli is characterized by its sharp and elongated ends of the elements. Composite range: Upper Cenomanian-Campanian. Remarks: Perch-Nielsen assigned this species to the genus Lithastrinus, though its number of elements is rather high and the holotype seems to have two cycles of elements in the margin (her pi. 5, fig. 7). The plate in the center, however, very much resembles those of Lithastrinus species. Composite range: Middle Campanian-Maastrichtian. Genus Stephanolithion Deflandre, 1939 Type species: Stephanolithion bigoti Deflandre, 1939 Remarks: The long protuberances on the margin are diagnostic for this genus. The central structure is composed of radial or near radial bars.

113 pi. 6, fig. 3-5, textfig ; Bukry, 1969, p. 43, pi. 21, fig. 7-11; Roth and Thierstein, 1972, pi. 16, fig Remarks: This species is characterized by its narrow circular margin with irregularly placed protuberances and a central structure composed of radial bars. Composite range: Tithonian-Maastrichtian. Family THORACOSPHAERACEAE Deflandre, 1952 Remarks: This small family includes one genus. Genus Thoracosphaera Kampter, 1927 Type species: Thoracosphaera pelagica Kamptner, 1927 Remarks: In this genus hollow globular calcareous nannofossils are grouped, which are composed of small sub circular units and show an aperture closed by an operculum. Thoracosphaera operculata Bramlette and Martini (pi. 10, fig. 11) Remarks: Complete specimens were found to be rare; generally only fragments were observed. The species differs from Thoracosphaera sp. by a fine irregular extinction pattern caused by the smaller units. Composite range: Upper Maastrichtian-Danian. Thoracosphaera Remarks: Rare small fragments with a coarse extinction pattern are placed here. Composite range: Upper Maastrichtian. sp. Genus Calculites Prins and Sissingh, 1977 Type species: Tetralithus obscurus Deflandre, Remarks: Calculites includes species, which are composed of a narrow margin of one cycle and a central area closed by a plate constructed of four

114 to eight elements. Prins and Sissingh (in Sissingh, 1977) describe this plate as a wall and thus as a part of the margin. Tetralithus obscurus Deflandre, 1959, p. 138, pi. 3, fig ; Bramlette and Martini, 1964, p. 320, pi. 4, fig ; Bukry, 1969, p. 63, pi. 37, fig Tetralithus ovalis Stradner, 1963, p. 12, pi. 3, fig Calculites obscurus (Deflandre) Prins and Sissingh, in Sissingh, 1977, p. 60. Calculites ovalis (Stradner) Prins and Sissingh, in Sissingh, 1977, p. 60. Remarks: As stated by Prins and Sissingh (in Sissingh, 1977) a wide and badly understood variation occurs in the genus Calculites. Only larger forms can be assigned to C. obscurus or C. ovalis on the basis of the position of the four large elements in the central area. For small specimens such assignments are doubtful, for which reason all our specimens with four large elements in the central area are placed in one group. Composite range: Middle Turonian-Maastrichtian. Genus Ceratolithoides Bramlette and Martini, 1964 Type species: Ceratolithoides k amp tneri Bramlette and Martini, Remarks: This genus includes cone-shaped calcareous nannofossils and nannofossils with the outline of a horseshoe. The fossils are composed of two layers, each of two to six elements, which layers are not equal in shape and not divided in a margin and a central area. An evolutionary lineage was recognized (see remarks on evolution). Ceratolithoides aculeus (Stradner) Prins and Sissingh (pi. 1, fig. 1-10, 12) Zygrhablithus aculeus Stradner, 1961, partim, p. 81, fig. 53, non fig. 54. Tetralithus sp. aff. T. aculeus (Stradner) Gartner, 1968, p. 43, pi. 9, fig. 5; pi. 13, fig. 5. Tetralithus aculeus (Stradner) Gartner, Manivit, 1971, p. 143, pi. 25, fig Ceratolithoides kamptneri Bramlette and Martini, Manivit, 1971, p. 132, pi. 12, fig Ceratolithoides aculeus (Stradner) Prins and Sissingh, in Sissingh, 1977, p. 60, pi. 1, fig. 8. Remarks: Six types could be recognized in this species (see remarks on evolution). Composite range: Lower Campanian-Maastrichtian.

115 Remarks: C. arcuatus shows an angle between the two long proximal elements of far more than 90, whereas in the other species of Ceratolithoides this angle is about 90 or less. These other species also have a slightly reduced top cycle. Composite range: Campanian-Maastrichtian. Ceratolithoides kamptneri Bramlette and Martini (pi. 1, fig. 11) Ceratolithoides kamptneri Bramlette and Martini, 1964, p. 308, pi. 6, fig ; non Manivit, 1971, p. 132, pi. 12, fig Tetralithus kamptneri (Bramlette and Martini) Verbeek, 1976b, p. 146, pi. 3, fig. 6. Remarks: This species is characterized by two long proximal elements and four very small distal elements. Composite range: Upper Maastrichtian. Genus Hayesites Manivit, Type species: Hayesites albiensis Manivit, Remarks: Hayesites differs from Rucinolithus Stover by a conical shape and sideward extending arms. Remarks: This species is rare in the Albian rocks of EI Burrueco. It differs from Hayesites bulbus Thierstein by its short and pointed arms. Composite range: Albian. Genus Lucianorhabdus Deflandre, 1959, emend. Type species: Lucianorhabdus cayeuxi Deflandre, Description: Rhabdoliths without a basal disc or with a closed basal disc, which is neither differentiated into a margin and a central area nor in shields or rim tiers. Four to eight ridges extend from the central process. A plug or a cycle of four to twelve crystals are sometimes present at the distal end of the central process. The surface of the coccolith is granulate. Comparison: The genus Lucianorhabdus differs from all genera of the families Eiffellithaceae and Podorhabdaceae by the absence of a basal disc or one which is not divided in a margin and a central area or in tiers and shields. This emendation means that the genus Isocrystallithus Verbeek

116 (1976a) becomes a junior synonym of Lucianorhabdus, as was proposed by Prins and Sissingh (in Sissingh, 1977). Remarks: Deflandre (1959) described four long and broad elements as the only feature for the genus, in addition to a great number of types of shape. Our emendation adapts his description to the information obtained by other authors afterwards. Specimens without secondary calcification show a crystallographic construction similar to the holococcoliths described by Gartner and Bukry (1969). The species assigned to Lucianorhabdus may be the motile stage of other species, as for instance Crystallolithus hyalinus Gaarder and Markali is the motile stage of Coccolithus pelagicus (Wallich) (see Parke and Adams, 1960). Lucianorhabdus arcuatus Forchheimer (pi. 11, fig. 1) Lucianorhabdus cayeuxi Deflandre, 1959, partim, p. 142, pi. 4, fig. 20, 25 non pi. 4, fig , 22-24; Gorka, 1963, partim, p. 24, pi. 2, fig. 7, textpi. 2, fig. 8 non pi. 2, fig. 6, 8-9, textpi. 2, fig Lucianorhabdus arcuatus Forchheimer, 1972, p. 69, pi. 10, fig. 5. Remarks: L. arcuatus is the only species of the genus showing a curved central process. A small basal disc and a plug may be present. Composite range: Santonian-Maastrichtian. Lucianorhabdus cayeuxii Deflandre (pi. 11, fig. 2-3) Lucianorhabdus cayeuxi Deflandre, 1959, partim, p. 142, pi. 4, fig , non pi. 4, fig. 20,25. Remarks: Only conical or pillar-shaped forms are included in this species. The basal disc is thin and about as broad as the central process, or it is absent. The composite range given here is only based on the results of the present study, because the ranges reported in the literature are perhaps doubtful, because other forms may have been included, which are not in agreement with the restricted species interpretation used in this paper. Composite range: Campanian-Maastrichtian. Lucianorhabdus compactus (Verbeek) Prins and Sissingh (pi. 11, fig. 4) Isocrysta11ithus compactus Verbeek, 1976a, p. 78, pi. 2, fig Lucianorhabdus compactus (Verbeek) Prins and Sissingh, in Sissingh, 1977, p. 61.

117 Remarks: After the emendation of Lucianorhabdus this species can be placed in this genus. It is recognizable by a distinct basal disc, a straight central process and a plug at the distal side of the central process. In older forms the basal disc is smaller than in the forms found by Verbeek (197 6a) in the Cenomanian type area. There seems to be an increase in length of the central process. Composite range: Albian-Santonian. Lucianorhabdus maleformis Reinhardt (pi. 11, fig. 6) Lucianorhabdus cayeuxi Deflandre. Cohen, 1965, partirn, p. 35, pi. 5, fig. a-c non pi. 5, fig. d-e; Thierstein, 1976, p. 350, pi. 5, fig Lucianorhabdus maleformis Reinhardt, 1966a, p. 42, pi. 21, fig. 5, 7; Thierstein, 1971a, p. 36, pi. 3, fig ; Risatti, 1973, p. 29, pi. 7, fig Remarks: L. maleformis is characterized by its rather short and conical central process and the distinct basal disc. The specimens recorded in this study have a shorter central process than figured by Reinhardt. All species of the genus Semihololithus differ from L. maleformis by the presence of large elements in the basal disc. Composite range: Turonian-Maastrichtian. Lucianorhabdus quadrifidus F orchheimer (pi. 11, fig. 7) Remarks: Diagnostic features are the cycle of elements with irregular ridges and the thin basal disc. Composite range: Upper Santonian-Lower Campanian. Lucianorhabdus scotus (Risatti) n. comb. (pi. 11, fig. 5) Remarks: L. scotus is distinguished by a narrow and small basal disc with a long and pointed central process. It has the same granulate structure as L. cayeuxii, which is the reason to place this species in the genus Lucianorhabdus. Ridges which are present in the other species of Lucianorhabdus, were not observed. Composite range: Upper Turonian-Middle Campanian.

118 Genus Marthasterites Deflandre, 1959 Type species: Discoaster (?) furcatus Deflandre, Remarks: This genus comprises all three-rayed calcareous nannofossils constructed of one element. Marthasterites furcatus (Deflandre) Deflandre (pi. 11, fig. 8, 9) Discoaster (?) furcatus Deflandre, 1954, p. 168, pi. 13, fig. 14. Marthasterites furcatus (Deflandre) Deflandre, 1959, p. 139, pi. 2, fig. 3-12; pi. 3, fig Marthasterites furcatus var. crassus Deflandre, 1959, p. 139, pi. 2, fig. 17; pi. 3, fig Marthasterites furcatus var. bramlettei Deflandre, 1959, p. 139, pi. 3, fig. 2. Marthasterites jucundus Deflandre, 1959, p. 140, pi. 2, fig ; Bukry, 1969, p. 66, pi. 39, fig. 8. Marthasterites jucundus var. dentiferus Deflandre, 1959, p. 140, pi. 2, fig ,22. Marthasterites furcatus furcatus (Deflandre), Deflandre, Bukry, 1969, p. 65, pi. 39, fig Marthasteritesfurcatus crassus Deflandre. Bukry, 1969, p. 65, pi. 39, fig. 5. Marthasterites furcatus simplex Bukry, 1969, p. 66, p. 39, fig Remarks: M. furcatus shows a large variation in size and in number of protuberances at the end of the arms. This number may even vary in one specimen. On several types of this variation range two species and five subspecies have been erected, but in most of the samples from our Coniacian to Lower Campanian sediments transitional forms were found. Therefore all these species and subspecies, except Marthasterites inconspicuus Deflandre, are placed in synonymy. M. inconspicuus is different by its smooth, slender and pointed arms. Composite range: Lower Coniacian-Lower Campanian. Marthasterites inconspicuus Deflandre (pi. 11, fig. 10) Marthasterites inconspicuus Deflandre, 1959, p. 140, pi. 3, fig. 6-14; Bramlette and Martini, 1964, p.314, pi. 6, fig. 6; Gartner, 1968, p. 42, pi. 2, fig. 9; pi. 10, fig. 10; Manivit, 1971, p. 141, pi. 16, fig Remarks: Although the original figures of Deflandre only show almost triangular specimens, Bramlette and Martini, Gartner and Manivit figured and.d.escribed small forms with three thin, smooth and pointed arms as M. inconspicuus. Only such forms were found in our material. Composite range: Middle Turonian-Maastrichtian. Genus Micula Vekshina, Type species: Micula decussata Vekshina, 1959.

119 Remarks: Some confusion exists about the structure of the fossils assigned to Micula. A paper on this subject and on the evolution of this genus is in preparation by Sissingh. In our material the ultrastructure was not well visible, because of overgrowth with secondary calcite. The cube-shaped and "open umbrella-shaped" fossils with high birefringence and a cross-shaped extinction pattern in cross-polarized light have been assigned to Micula. Micula concava (Stradner) Bukry (pi. 11, fig. 11) Nannotetraster concavus Stradner, in Martini and Stradner, 1960, p. 269, fig. 18a-d; Stradner, 1961, p. 83, fig ; Stradner and Papp, 1961, p. 102, pl. 31, fig. 1a-d, textfig. 10-1, 19-1, Micula staurophora (Gardet) Stradner, 1963, partim, p. 14, pi. 4, fig. 12, 12b-c non pl. 12, fig. 12a. Micula decussata concava (Sradner) Bukry, 1969, p. 67, pl. 40, fig Micula concava (Stradner) Bukry, Verbeek, 1976b, p. 147, pi. 2, fig. 3. Remarks: The processes at the corners of this nannofossil distinguish M. concava from M. decussata. M. concava shows longer processes and more strongly depressed edges in Upper Campanian and Maastrichtian sediments. Composite range: Santonian-Maastrichtian. Micula decussata Vekshina (pi. 11, fig. 12) Micula decussata Vekshina, 1959, p. 71, pl.1, fig. 6;pl. 2, fig. 11; Bukry, 1969, p. 67, pl. 40, fig Micula staurophora (Gardet) Stradner, 1963, partim, p. 14, pi. 4, fig. 12a non pi. 4, fig. 12, 12b-c. Remarks: The cube-shape and slightly depressed edges are characteristic for this species. Gardet (1955) described Discoaster staurophorus as a plate with ridges parellel to the diagonals of that plate. Many authors consider D. staurophorus as a senior synonym of M. decussata. Since M. decussata is not a plate and has no ridges,d. staurophor"us cannot be synonymous with M. decussata; probably it is a species of the genus Nannotetraster Achuthan and Stradner (1969). Composite range: Middle Coniacian-Maastrichtian. Micula murus (Martini) Bukry (pi. 11, fig. 13) Tetralithus murus Martini, 1961, p. 4, pl. 1, fig. 6, pl. 4, fig. 42; Bramlette and Martini, 1964, p. 320, pi. 6, fig Micula mura (Martini) Bukry, 1973, p. 679.

120 Remarks: Doubt is raised about the species concept of M. murus of Verbeek (197 6b), who placed all specimens in which the four large elements have a spiral arrangement with some of the elements elongated, in Tetralithus mutus. This operational definition did not work, though it seemed in accordance with the original description of Martini (1961). Therefore only those specimens in which the elements are distincly elongated and curved (cf. Bramlette and Martini, 1964) are recorded now as M. murus. As a consequence the lower limit of the M. murus Zone has to be shifted to younger sediments. Composite range: Upper Maastrichtian. Genus Nannoconus Kamptner, 1931 Type species: Nannoconus steinmanni Kamptner, Remarks: These column or basket-shaped microfossils are usually represented by fragments only. Nannoconus truitti Bronnimann (pi. 12, fig. 3,4) Nannoconus truitti Bronnimann, 1955, p. 38, pi. 2, fig. 2-5, 7; Trejo, 1960, p. 298, textfig ; Deflandre and Deflandre-Regaud, 1959, p. 177, pi. 1, fig. 1-6; Manivit, 1971, p. 136, pi. 32, fig. 6,8,10, Remarks: Basket-shaped forms and rare short cylindrical specimens and fragments with a broad central canal resemble the third nannoconus group of Aubry (1974). Composite range: Lower Berriasian-Campanian. Genus Polycladolithus Deflandre, 1954 Type species: Polycladolithus operosus Deflandre, Remarks: All small irregular calcite bodies with irregular to circular depressions are included in Polycladolithus. Polycladolithus sp. (pi. 12, fig. 1-2) Remarks: The irregularly shaped calcite bodies with oval de'pressions, which were found in samples Kef 27 and 46, are assigned to the genus Polycladolithus, though this genus is only known from Tertiary rocks. Composite range: Lower Santonian-Lower Campanian.

121 Genus Polycostella Thierstein, 1971 Type species: Polycostella senaria Thierstein, Remarks: The ridges on the surface of the type species are too evident to consider the type species as a synonym of Nannoconus colomi (de Lapparent), as was suggested by Griln and Allemann (1975). Polycostella? sp. (pi. 12, fig. 5) Remarks: The short, sometimes slightly conical, but generally straight, columns with four to eight ridges are listed as Polycostella? sp. Previously this genus was known only from Lower Tithonian to Upper Berriasian sediments. Composite range: Middle Albian-Middle Cenomanian. Genus Quadmm Prins and Perch-Nielsen, 1977 Type species: Quadrum gartneri Prins and Perch-Nielsen, 1977 Remarks: This genus was introduced by Prins and Perch-Nielsen (in Manivit et al., 1977) to replace the genus Tetralithus Gardet, of which the type species is not well known from Cretaceous sediments. This gave the opportunity to make a new subdivision of the group of species, so far included in Tetralithus) into three genera: Calculites) Ceratolithoides and Quadrum. Calculites includes the species with a margin and a central area, Ceratolithoides the cone- and horseshoe-shaped species, and Quadrum the species composed of one or two layers of four radiating calcite units. Quadmm gartneri Prins and Perch-Nielsen (pi. 12, fig. 6-8) Tetralithus gothicus Deflandre. Gartner, 1968, p. 42, pl. 24, fig. 4. Micula staurophora (Gardet) Stradner. Thierstein, 1974, partim, pl. 12, fig. 4-8 non pl. 12, fig. 1-3, Tetralithus pyramidus Gardet. Verbeek, 1976b, pi. 1, fig. 4, 6. Quadrumgartneri Prins and Perch-Nielsen, in Manivit et al., 1971, p. 177, pl. 1, fig Remarks: The cube-shape and the absence of protuberances on the corners are characteristic for this species, which may be constructed of one or two layers. Rare specimens with three instead of four calcite units were found as well. Composite range: Upper Cenomanian-Maastrichtian.

122 Quadrum gothicum (Deflandre) Prins and Perch-Nielsen (pi. 12, fig. 10) Tetralithus gothicus Deflandre, 1959, pi. 3, fig. 25; Stradner, in Stradner and Papp, 1961, p. 124, pi. 14, fig. 13, textfig. 13/2; Martini, 1961, p. 4, pi. 1, fig. 4; Verbeek, 1976b, partim, p. 145, pi. 2, fig. 8 non pi. 3, fig. 1. Quadrum gothicum (Deflandre) Prins and Perch-Nielsen, 1977, p Remarks: Q. gothicum is distinguished by its four elongated elements that give the fossil a star-shaped outline. Because of its distinctly different appearance level Quadrum trifidum (Stradner) is also recognized, although both species have basically the same construction. Q. gothicum differs from Q. trifidum by its four elements instead of three and from Quadrum nitidum (Martini) in being composed of one layer. Prins and Perch-Nielsen (in Manivit et ai., 1977) include in Q. gothicum only specimens with four very long arms and they assign specimens with shorter arms to Q. nitidum. In the present study both these types have been incorparated in Q. gothicum, whereas for Q. nitidum a different species concept is used. Composite range: Middle Campanian-Lower Maastrichtian. Quadrum nitidum (Martini) Prins and Perch-Nielsen (pi. 12, fig. 9) Tetralithus nitidus Martini, 1961, p. 4, pi. 1, fig. 5; pi. 4, fig. 41; Verbeek, 1976b, p. 146, pi. 2, fig. 4. Quadrum nitidum (Martini) Prins and Perch-Nielsen, in Manivit et al., 1977, p Remarks: This species is constructed of two layers of four elements; the elements of one of these layers are elongated. This species concept is in accordance with the original description of Martini (1961). Specimens composed of one layer of four more or less elongated elements have to be placed in Q. gothicum. Composite range: Middle Santonian-Lower Maastrichtian. Tetralithus quadratus Stradner, 1961, p. 86, fig. 2; Bukry, 1969, p. 64, pi. 38, fig. 2; Manivit, 1971, p. 145, pi. 25, fig. 9, 10. Remarks: This species is characterized by four triangular elements forming a square outline. Because a margin is missing this species cannot be assigned to the genus Calculites, but must be placed in Quadrum. Composite range: Lower Santonian-Maastrichtian.

123 Quadrum trifidum (Stradner) Prins and Perch-Nielsen (pi. 12, fig. 11) Tetralithus gothicus trifidus Stradner, in Stradner and Papp, 1961, p. 124, textftg. 23/3. Tetralithus trifidus (Stradner) Bukry, 1973, p Tetralithus gothicus Deflandre. Verbeek, 1976b, partim, p. 145, pi. 3, ftg. 1 non pi. 2, ftg. 8. Quadrum trifidum (Stradner) Prins and Perch-Nielsen, in Manivit et ai., 1977, p Remarks: Q. trifidum is distinguishable by its three elongated arms. Its appearance level is somewhat higher than that of Q. gothicum, which is an additional argument to separate both species. Composite range: Upper Campanian-Lower Maastrichtian. Genus Rucinolithus Stover, 1966 Type species: Rucinolithus hayii Stover, 1966 Remarks: All flat coccoliths with five or more strongly imbricate elements are included in this genus. Rucinolithus hayii Stover (p. 12, fig. 13) Rucinolithus hayii Stover, 1966, p. 156, pi. 7, ftg. 21; pi. 9, fig. 22; Cepek and Hay, 1969a, ftg. 4, fig. 2. Discoaster? hayii Bukry, 1969, p. 65, pi. 38, ftg Rucinolithus cf. hayii Stover, Manivit, 1971, p. 142, pi. 25, flg Remarks: This species is characterized by its five or six elongated elements. It may have a knob in the center. Composite range: Middle Santonian-Campanian. Rucinolithus irregularis Thierstein (pi. 12, fig. 12) Rucinolithus irregularis Thierstein, in Roth and Thierstein, 1972, p. 438, pi. 2, fig ; Thierstein, 1973, p. 45, pi. 3, ftg Remarks: Thierstein (1972) described this species in detail and differentiated it from Rucinolithus wisei Thierstein by its anti-clockwise imbrication of the elements. Composite range: Lower Aptian-Upper Albian.

124 In review, it was found that the model describing two developments in the evolution of Eiffellithus had to be revised. The discussions over the gradual changes in the angle between the longer bar of the central structure and the major axis of the elliptical disc, called a and ~ (as presented in figs. 18 and 19) remain valid. However, as seen from a standard orientation, the turning of the bars is different from what is presented in the text. The two rotations measured, involve the same bar rather than the rotation of one bar and then the other. As viewed from the distal side, the longer bar orientated in the direction of the major axis of the ellipse begins to gradually turn anti-clockwise in successive samples from the EI Burrueco section (SP 411-SP 310). The transition from Vekshinella angusta to Eiffellithus turriseiffeli is chosen when this bar makes an angle of more than 20 with the longer axis of the ellipse (SP 415). The same bar continues to turn anti-clockwise until the average angle approaches 45 which is typical for Eiffellithus turriseiffeli (fig. 18). \trend Opening \rend Closing ~~~~~ In the section from Kat el Hamra, successive Eiffellithus populations begin to be more variable in the position of the bars in relation to the axes of the elliptical disc. This is shown by the greater variation in the angle between the rotating bar measured and the major axis of the ellipse, called ~ in fig. 19 (samples Kef 9 - Kef 15). Those specimens with ~ values greater than 20 remain in Eiffellithus turriseiffeli; specimens with values less than 20 are considered to represent the first Eiffellithus eximius (Kef 12-15). As viewed from the distal side, the rotating bar measured turns clockwise and positionally represents the same bar as in the Vekshinella angusta-eiffellithus turriseiffeli lineage. From a standard orientation, the angles called a and ~ are measured from the same bar in relation to the longer axis of the ellipsoid disc and there is no need to distinguish an a and a ~ angle. It thus appears that E. eximius resembles v. angusta in bar pattern. Differentiation of both may be based on our observations that the former is accompanied by E. turriseiffeli, the latter is not. In addition, E. eximius commonly shows bifurcation at the ends of the bars, and the bars tend to be broader. In V. angusta the central area is more open.

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132 Fig. 1~3 Ceratolithoides oculeus (Stradner), type I, AFN 182, Utrecht slide CH 3833, location V + 7, + 2, fig. 1 side view, fig. 2 oblique distal view, fig. 3 oblique proximal view, 5000 x. Ceratolithoides aculeus (Stradner), type II, AFN 184, Utrecht slide CH 3774, location V + 3, + 7, side view, 5000 x. Ceratolithoides aculeus (Stradner), type III, AFN 188, Utrecht slide CH 3776, location V + 1, + 2, side view, 5000 x. Ceratolithoides aculeus (Stradner), type IV, AFN 189, Utrecht slide CH 3834 location V + 6, + 4, side view, 5000 x. Ceratolithoides aculeus (Stradner), type IV, AFN 199, Utrech t slide CH 3769, location V + 4, - 6, side view, 5000 x. Ceratolithoides aculeus (Stradner), type V, AFN 199, Utrecht slide CH 3778, location V - 1, + 1, side view, 5000 x. Ceratolithoides aculeus (Stradner), type V, AFN 199, Utrecht slide CH 3773, location V + 3, + 5, side view, 5000 x. Ceratolithoides aculeus (Stradner), type V, AFN 199, Utrecht slide CH 3773, location V - 2, + 5, side view, 5000 x. Fig. 11 Ceratolithoides kamp tneri Bramlette and Martini, AFN 199, Utrecht slide CH 3773, location V - 4, - 3, side view, 5000 x. Fig. 12 Ceratolithoides aculeus (Stradner), type VI, AFN 194, Utrecht slide CH 3855, location V - 7, ~ 5, side view, 5000 x.

133

134 Fig. 1 Arkhangelskiella specillata Vekshina, AFN 182, Utrecht slide CH 3388 location V + 3, + 9, oblique distal view, 5000 x. Fig. 2 Arkhangelskiella specillata Vekshina, AFN 182, Utrecht slide CH 3388 location V + 2, + 3, distal view, 2500 x. Fig. 3 Arkhangelskiella cymbiformis Vekshina, AFN 200, Utrecht slide CH 3770 location V - 3, + 4, distal view, 5000 x. Fig. 4 Arkhangelskiella cymbiformis Vekshina, AFN 200, Utrecht slide CH 3399 location V + 3, + 9, distal view, 2500 x. Fig. 5 Broinsonia enormis (Shumenko), Fr 1537, Utrecht slide CH 3746 location V - 5, + 3, oblique distal view, 5000 x. Fig. 6 Broinsonia jurtiva Bukry, Kef 37, Utrecht slide CH 3398 location V + 2, + 7, distal view, 5000 x. Fig. 7 Broinsonia furtiva Bukry, Kef 37, Utrecht slide CH 3398, location V + 1, + 4, distal view, 5000 x. Fig. 8 Broinsonia lacunosa Forchheimer, Kef 45, Utrecht slide CH 3759 location V + 4, + V, distal view, 5000 x. Fig. 9 Broinsonia lacunosa Forchheimer, Kef 29, Utrecht slide CH 3395, location V - 6, - 7, distal view, 5000 x. Fig. 10 Broinsonia parca (Stradner), Kef 46, Utrecht slide CH 3761, location V - 5, + 6, distal view, 2500 x. Fig. 11 Broinsonia parca (Stradner), AFN 189, Utrecht slide CH 3390 location V - 8, + 5, distal view, 5000 x. Fig. 12 Broinsonia signata (Noel), Kef 9, Utrecht slide CH 3777, location V - 4, + 1, distal view 5000 x.

135

136 Fig. 1 Gartnerago obliquum (Stradner), Kef 23, Utrecht slide CH 3392 location V + 3, + 6, distal view, 5000 x. Fig. 2 Gartnerago obliquum (Stradner), Kef 45, Utrecht slide CH 3759 location V - 4, - 3, proximal view, 5000 x. Fig. 3 Gartnerago sp., SP 323, Utrecht slide CH 3771, location V - 6, - 2, distal view, 5000 x. Fig. 4 Kamptnerius magnificus Deflandre, AFN 200, Utrecht slide CH 3763 location V + 1, + 7, distal view, 5000 x. Fig. 5 Kamptnerius magnificus Deflandre, AFN 200, Utrecht slide CH 3762 location V - 5, + 4, proximal view, 2500 x. Fig. 6 Kamptnerius tabulatus Perch-Nielsen, AFN 200, Utrecht slide CH 3389 location V - 8, - 4, distal view, 5000 x. Fig. 7 Kamptnerius tabulatus Perch-Nielsen, AFN 200, Utrecht slide CH 3389 location V - 5, - 6, proximal view, 5000 x. Fig. 8 Braarudosphaera bigelowi (Gran and Braarud) SP 413, Utrecht slide CH 3756 location V - 4, + 1, distal view 5000 x. Fig. 9 Bidiscus ignotus (Gorka), SP 122, Utrecht slide CH 3764 location V - 2, + 7, distal view, x. Fig. 10 Bidiscus rotatorius Bukry, AFN 199, Utrecht slide CH 3778 location V - 3, + 4, coccosphaere, 5000 x.

137

138 Biscutum cons tans (Gorka), SP 323, Utrecht slide CH 3765 location V + 1, - 5, proximal view, x. Cyclagelosphaera perforata (Perch-Nielsen), AFN 199, Utrecht slide CH 3775, location V-I, + 5, proximal view, x. Cyclagelosphaera margereli Noel, SP 415, Utrecht slide CH 3755 location V -2, -4, distal view, 5000 x. Manivitella pemmatoidea (Deflandre in Manivit), Fr 1140, Utrecht slide CH 3752, location V + 4, + 8, proximal view, 2500 x. Watznaueria biporta Bukry, AFN 199, Utrecht slide CH 3778 location V - 2, + 2, distal view, 5000 x. Watznaueria barnesae (Black), Fr 1140, Utrecht slide CH 3753 location V + 5, + 5, coccosphaere, 5000 x. Watznaueria communis Reinhardt, Fr 1144, Utrecht slide CH 3780 location V + 4, - 2, distal view, 5000 x. Ahmuellerella octoradiata (Gorka), Kef 27, Utrecht slide CH 3393 location V 6, + 8, distal view, 5000 x. Ahmuellerella regularis (Gorka), AFN 200, Utrecht slide CH 3763 location V + 4, - 6, distal view, 5000 x.

139

140 Fig. 1 Chiastozygus amphipons (Bramlette and Martini), AFN 184, Utrecht slide CH 3774, location V - 5, + 5, distal view, 5000 x. Fig. 2 Chiastozygus litterarius (Gorka), Fr 1144, Utrecht slide CH 3780 location V + 4, + 1, proximal view, 5000 x. Fig. 3 Chiastozygus litterarius (Gorka), Kef 45, Utrecht slide CH 3759 location V -6, - 3, distal view, 5000 x. Fig. 4 Chiastozygus interruptus Bukry, Kef 27, Utrecht slide CH 3393 location V - 7, - 6, distal view, 5000 x. Fig. 5 Discolithina spiralis (Pienaar), AFN 193, Utrecht slide CH 3769 location V + 3, - 7, proximal view, 5000 x. Fig. 6 Eiffellithus eximius (Stover), Kef 27, Utrecht slide CH 3393, location V + 8, + 5, distal view, 5000 x. Fig. 7 Eiffellithus eximius (Stover), Kef 17, Utrecht slide CH 3748 location V + 2, - 9, oblique distal view, 5000 x. Fig. 8 Eiffellithus turriseiffeli (Deflandre), AFN 199, Utrecht slide CH 3778, location V - 3, + 5, oblique distal view, 5000 x. Fig. 9 Eiffellithus turriseiffeli (Deflandre), AFN 199, Utrecht slide CH 3778, location V - 6, - 4, distal view, 5000 x. Fig. 10 Eiffellithus parallelus Perch-Nielsen, AFN 199, Utrecht slide CH 3775, location V + 4, + 5, distal view, 5000 x. Fig. 11 Parhabdolithus embergeri (Noel), SP 122, Utrecht slide CH 3764 location V - 7, - 3, distal view, 5000 x. Fig. 12 Parhabdolithus embergeri (Noel), Kef 13, Utrecht slide CH 3391 location V - 2, + 8, central process, 2500 x.

141

142 Fig. 1 Reinhardtites anthophorus (Deflandre), AFN 188, Utrecht slide CH 3780 location V - 2, + 6, distal view, 5000 x. Fig. 2 Reinhardtites anthophorus (Deflandre), AFN 184, Utrecht slide CH 3774 location V - 6, + 5, distal view, 5000 x. Fig. 3 Reinhardtites brooksii (Bukry). AFN 182, Utrecht slide CH 3388 location V - 3, + 8, distal view, 5000 x. Fig. 4 Reinhardtites miniporus (Reinhardt and Gorka), SP 300, Utrecht slide CH 3768, location V - 6, + 3, distal view, x. Fig. 5 Reinhardtites miniporus (Reinhardt and Gorka) SP 300, Utrecht slide CH 3767, location V + 7, + 2, proximal view, x. Fig. 6 Rhagodiscus angustus (Stradner), AFN 199, Utrecht slide CH 3773 location V + 1, + 5, distal view, 5000 x. Fig. 7 Rhagodiscus asper (Stradner), Fr 1140, Utrecht slide CH 3752 location V + 6, + 7, oblique distal view, 5000 x. Fig. 8 Rhagodiscus asper (Stradner), Fr 1140, Utrecht slide CH 3752 location V + 7, + 6, distal view, 5000 x. Fig. 9 Rhagodiscus splendens (Deflandre), Fr 1140, Utrecht slide CH 3752 location V - 2, + 6, distal view, 5000 x. Fig. 10 Rhagodicus reniformis Persch-Nielsen, AFN 200, Utrecht slide CH 3389, location V - 4, - 6, distal view, 5000 x. Fig. 11 Vekshinella angusta (Stover), SP 413, Utrecht slide CH 3756 location V - 4, - 7, distal view, 5000 x. Fig. 12 Vekshinella angusta (Stover), Fr 1140, Utrecht slide CH 3752 location V + 7, + 3, distal view, x.

143

144 Fig. 1 Tegumentum stradneri Thierstein, Fr 1140, Utrecht slide CH 3752 location V + 8, + 4, distal view, 5000 x. Fig. 2 Tranolithus orionatus (Reinhardt), Fr 1537, Utrecht slide CH 3746 location V - 4, + 9, distal view, 5000 x. Fig. 3 Tranolithus orionatus (Reinhardt), Fr 1537, Utrecht slide CH 3746 location V - 1, + 2, distal view, 5000 x. Fig. 4 Tranolithus orionatus (Reinhardt), Fr 1537, Utrecht slide CH 3749 location V + 2, + 9, distal view, 5000 x. Fig. 5 Vekshinella bochotnicae (Gorka), SP 122, Utrecht slide CH 3765 location V + 2, + 1, distal view, 5000 x. Fig. 6 Vekshinella crux (Deflandre and Fert), AFN 199, Utrecht slide CH 3775, location V - 2, + 6, oblique distal view, 5000 x. Fig. 7 Zygodiscus acanthus (Reinhardt), SP 300, Utrecht slide CH 3767 location V + 5, + 3, distal view, 5000 x. Fig. 8 Zygodiscus diplogrammus (Deflandre), Fr 1140, Utrecht slide CH 3752 location V + 6, + 5, proximal view, 5000 x. Fig. 9 Zygodiscus minimus Bukry, SP 300, Utrecht slid.e CH 3767 location V + 7, + 2, distal view, x. Fig. 10 Zygodiscus elegans Gartner, Fr 1537, Utrecht slide CH 3746 location V + 4, - 3, distal view, 5000 x. Fig.11 Zygodiscus spiralis Bramlette and Martini, AFN 200, Utrecht slide CH 3399, location V + 7, + 2, distal view, 5000 x. Fig. 12 Zygodiscus spiralis Bramlette and Martini, Kef 44, Utrecht slide CH 3750, location V + 4, - 9, proximal view, x.

145

146 Zygodiscus theta (Black), Fr 1537, Utrecht slide CH 3749, location V + 5, - 6, distal view, 5000 x. Lithraphidites alatus Thierstein, SP 413, Utrecht slide CH 3782, location outside grid, side view, 5000 x. Lithraphidites acutum Verbeek and Manivit, Kef 9, Utrecht slide CH 3757, location V + 7, + 1, side view, 5000 x. Lithraphidites carniolensis Deflandre, Fr 1140, Utrecht slide CH 3752, location V + 3, + 7, side view, 2500 x. Lithraphidites quadratus Bramlette and Martini, AFN 199, Utrecht slide CH 3775, location V - 4, + 7, side view, 5000 x. Microrhabdulus belgicus Hay and Towe, Kef 23, Utrecht slide CH 3392, location V - 7, + 5, side view, 5000 x. Microrhabdulus decoratus Deflandre, AFN 188, Utrecht slide CH 3776, location V + 1, + 6, side view 2500 x. Cretarhabdus loriei Gartner, Kef 1, Utrecht slide CH 3747, location V - 7, + 7, distal view, 5000 x. Cretarhabdus surirelles (Deflandre), Fr 1140, Utrecht slide CH 3752, location V + 3, - 2, distal view, 5000 x. Fig Cribrocorona gallica (Stradner), AFN 199, Utrecht slide CH 3775 location V - 2, + 6, 10 oblique distal view, 11 distal view, 5000 x. Cribrocorona gallica (Stradner), AFN 200, Utrecht slide CH 3399, location V + 2, - 4, distal view, 5000 x.

147

148 Cribrosphaerella ehrenbergii (Arkhangelsky), AFN 188, Utrecht slide CH 3781, location V + 5, + 4, distal view, 5000 x. Cribrosphaerella pelta Gartner, AFN 199, Utrecht slide CH 5773, location V + 1, + 6, distal view, 5000 x. Cribrosphaerella circula (Risatti), AFN 199, Utrecht slide CH 3773, location V + 3, + 7, distal view, 5000 x. Cribrosphaerella circula (Risatti), AFN 199, Utrecht slide CH 3778, location V - 2, + 6, proximal view, 5000 x. Cruciellipsis chiasta (Worsley), Fr 1140, Utrecht slide CH 3752, location V + 9, + 2, distal view, 5000 x. Cruciellipsis cuvillieri (Manivit), Fr 1547, Utrecht slide CH 3754, location V + 7, + 3, distal view, 5000 x. Gaarderella granulifera Black, Fr 1149, Utrecht slide CH 3779, location V - 4, + 6, 7 oblique proximal view, 8 proximal view, 5000 x. Prediscosphaera columnata (Stover), Fr 1149, Utrecht slide CH 3779, location V - 3, + 6, distal view, x. Podorhabdus coronadventis (Reinhardt), Fr 1140, Utrecht slide CH 3752, location V - 7, + 7, distal view, 5000 x. Podorhabdus decorus (Deflandre), AFN 200, Utrecht slide CH 3772, location V + 3, + 7, distal view, 5000 x. Podorhabdus dietzmannii (Reinhardt), Fr 1537, Utrecht slide CH V + 4, + 2, distal view, 5000 x.

149

150 Fig. 1 Prediscosphaera cretacea (Arkhangelsky), AFN 199, Utrecht slide CH 3771, location V + 3, + 6, distal view, 5000 x. Fig. 2 Prediscosphaera cretacea (Arkhangelsky), AFN 199, Utrecht slide CH 3775, location V - 1, + 5, side view, 5000 x. Fig. 3 Prediscosphaera quadripunctata (Gorka), AFN 200, Utrecht slide CH 3762, location V - 5, + 1, distal view, x. Fig. 4 Corollithion? completum Perch-Nielsen, Kef 9, Utrecht slide CH 3757, location V - 6, + 2, distal view, 5000 x. Fig.5-7 Cylindralithus serratus Bramlette and Martini, AFN 199, Utrecht slide CH 3775, location V - 3, - 6, 5 and 6 oblique proximal views, 7 proximal view, 5000 x. Fig. 8 Cylindralithus serratus Bramlette and Martini, Fr 1544,Utrecht slide CH.3751, location V + 1, + 3, oblique distal view, 5000 x. Fig. 9 Lithastrinus grilli Stradner, Kef 27, Utrecht slide CH 3393, location V + 8, + 3, distal view, 5000 x. Fig. 10 Lithastrinus floralis Stradner, Kef 13, Utrecht slide CH 3391, location V - 4, + 9, distal view, 5000 x. Fig. 11 Thoracosphaera operculata Bramlette and Martini, AFN 202, Utrecht slide CH 3760, location V + 5, + 4, 2500 x.

151

152 Lucianorhabdus arcuatus Forchheimer, AFN 184, Utrecht slide CH 3774, location V - 4, + 5, side view, 2500 x. Lucianorhabdus cayeuxii Deflandre, AFN 188, Utrecht slide CH 3781, location V - 3, + 6, side view, 2500 x. Lucianorhabdus cayeuxii Deflandre, AFN 188, Utrecht slide CH 3781, location V - 2, + 7, side view, 2500 x. Lucianarhabdus compactus (Verbeek), Kef 23, Utrecht slide CH 3758, location V + 6, - 3, side view, 2500 x. Lucianorhabdus scotus (Risatti), AFN 182, Utrecht slide CH 3389, location V - 1, + 10, side view, 2500 x. Lucianorhabdus malefarmis Reinhardt, Kef 23, Utrecht slide CH 3758, location V + 4, + 5, side view, 5000 x. Lucianarhabdus quadrifidus Forchheimer, Kef 45, Utrecht slide CH 3759, location V - 4, + 5, side view 2500 x. Marthasterites furcatus Deflandre, Kef 45, Utrecht slide CH 3759, location V - 5, + 5, 2500 x. Marthasterites furcatus Deflandre, Kef 23, Utrecht slide CH 3392, location V + 4, + 2, 2500 x. Marthasterites inconspicuus Deflandre, AFN 200, Utrecht slide CH 3391, location V + 7, + 3,5000 x. Fig. 11 Fig. 12 Fig. 13 Micula concava (Stradner), AFN 202, Utrecht slide CH 3760, location V - 6, - 2, 2500 x. Micula decussata Vekshina, AFN 199, Utrecht slide CH 3373, location V + 1, + 6, x. Micula murus (Martini), AFN 202, Utrecht slide CH 3760, location V - 7, + 1, distal view, 5000 x.

153

154 Fig 1 Polycladolithus sp., Kef 27, Utrecht slide CH 3393, location V - 4, - 2, distal view, 2500 x. Fig. 2 Polycladolithus sp., Kef 27, Utrecht slide CH 3393, location V - 9, + 2, side? view, 2500 x. Fig. 3 Nannoconus truitti Bronnimann, SP 323, Utrecht slide CH 3766, location V - 4, + 5, side view, 5000 x. Fig. 4 Nannoconus truitti Bronnimann, Fr 1547, Utrecht slide CH 3754, location V - 3, + 4, side view, 2500 x. Fig. 5 Polycostella? sp., SP 323, Utrecht slide CH 3771, location V - 6, + 2, proximal? view, 2500 x. Fig. 6-8 Quadrum gartneri Prins and Perch-Nielsen, Kef 17, Utrecht slide CH 3778, location V - 2, - 7, different views same specimen, 5000 x. Fig. 9 Quadrum nitidum (Martini), AFN 189, Utrecht slide CH 3390, location V - 2, + 4, distal? view, 5000 x. Fig. 10 Quadrum gothicum (Deflandre), AFN 188, Utrecht slide CH 3791, location V + 4, + 6, distal? view, 5000 x. Fig.11 Quadrum trifidum (Stradner), AFN 188, Utrecht slide CH 3776, location V + 2, + 2, distal? view, 2500 x. Fig. 12 Rucinolithus irregularis Thierstein, SP 413; Utrecht slide CH 3756, location V - 1, - 5, distal? view, 5000 x. Fig. 13 Rucinolithus hayii Stover, AFN 182, Utrecht slide CH 3388, location V + 2, + 8, distal view, 5000 x.

155