Do calcareous dominated shelf foraminferal assemblages leave worthwhile ecological information after their dissolution?

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1 311 Do calcareous dominated shelf foraminferal assemblages leave worthwhile ecological information after their dissolution? JOHN W. MURRAY 1 and ELISABETH AL VE 2 1. School of Ocean and Earth Science, Southampton Oceanography Centre, European Way, Southampton 514 3ZH, UK 2. Department of Geology, University of Oslo, P.O.Box 147 Blindern, N-316 Oslo, Norway ABSTRACT This study strongly indicates that in the shelf environments SW of Britain, the organic cemented agglutinated foraminifera have a community structure comparable to that of the whole original dead foraminiferal community even though they are present only as subordinate components «5%). This is manifested through similarities in faunal distributions, the relative abundances of attached and clinging forms, and the diversity patterns, particularly the alpha index. The agglutinated assemblages have been obtained by dissolving the original dead assemblages (ODAs) in weak acid, and this leaves residual (organic cemented agglutinated) acid treated assemblages (ATAs). The new diversity data have been combined with similar, previously published data and show that there is a significant positive correlation between the ODAs and ATAs; there is increasing diversity from marginal marine to abyssal environments and the alpha index shows a clear separation between the major environmental settings. These findings are of fundamental importance for palaeoenvironmental interpretations because they imply that some fossil agglutinated assemblages with an ecologically meaningful faunal composition can represent the residues left after dissolution of originally calcareous dominated assemblages. They also show that useful ecological information can be obtained by analysing solely the organic cemented agglutinated assemblages in those cases where there is reason to believe that parts of the calcareous components have been selectively dissolved. Therefore, the answer to the question posed by the title is 'yes'. INTRODUCTION The enigma of fossil assemblages composed exclusively or almost exclusively of non-calcareous foraminfera has been addressed by us in a series of experimental studies (Alve & Murray, 1994; 1995; Murray & Alve, 1994; 1999a,b). In order to shed some light on this problem, we have simulated possible postmortem dissolution loss of calcareous tests through controlled dissolution of modern assemblages from various environments. In the present study we have extended the range of our investigation by examining the high energy, continental shelf assemblages from the west of southern England. In contrast to our previously investigated areas, many of the dead assemblages here are dominated by calcareous cemented agglutinated taxa and these, of course, are lost if the material is subjected to dissolution although they may leave traces as glauconitic chamber infillings (see George & Murray, 1977). The aim is to determine whether the organic cemented agglutinated assemblages left after acid treatment (acid treated assemblage = ATA) carry as much ecological information as the original dead assemblages (ODAs) from which they were drawn. If this is the case, it will have two major implications for the use of benthic foraminifera in palaeoecological interpretations: 1) It will represent a strong argument for inferring that some agglutinated fossil assemblages, which otherwise would be interpreted as primary, represent the residues left after carbonate dissolution of the original assemblages. 2) It will extend the application of benthic foraminifera in palaeoenvironmental investigations as it will allow interpretations to be made solely based on the agglutinated assemblages if there is reason to believe that carbonate dissolution has removed important components of the calcareous assemblages. In addition, there is a very positive benefit that investigations like this provide unique information about the relative abundance and distribution of organic cemented agglutinated taxa which are normally swamped by calcareous tests. AREA INVESTIGATED The continental shelf to the west of southern Britain slopes gently from the nearshore area to the shelf In: Hart, M.B., Kaminski, M.A., & Smart, C.W. (eds.) 2. Proceedings of the Fifth International Workshop on Agglutinated Foraminifera. Grzybowski Foundation Special Publication, 7,

2 312 J,W. Murray & E. Alve lo"w 9"W 8"W 7"W 6"W 5"W 4'W 3"W 2'W 5l'N 'N 49'N Figure I, Map of the continental shelf to the west and south of SW England with stations and bathymetry, Depth contours in metres, break at around 18 m. It has a long geological history but the most recent influences have been subaerial exposure during the Last Glacial Maximum of those regions now submerged from the shoreline to a depth of between 11 and 12 m on the shelf (Bouysse et al., 1976) followed by flooding during the Flandrian transgression (Hamilton et al., 198). At water depths greater than around 12 m, elongate sand bodies some tens of metres high and with a NE SW trend are superimposed on the gently sloping shelf (Figure 1). These are thought to have formed under the influence of tidal currents during an early Holocene period of lower sea level and are now not actively forming (Stride, 1982, p. 113). The study region is divided into 6 geographic areas (Figure 2); some of the environmental features are summarised in Table 1. All areas are fully marine but they show varying ranges of bottom water temperatures. This is in relation to the presence or absence of thermal layering of the water column during the summer months. A thermocline is present at depths down to around 5 m in the areas having a water depth greater than around 8 m while areas shallower than this are vertically mixed throughout the year, The cause of mixing is tidal and wave energy. Because warm surface water is not mixed down to the bottom until the autumn, that is the time of slightly higher bottom temperatures. Tidal energy is particularly high in the Approaches to the Bristol Channel and it is quite high in the Western Approaches and Western Channel. The slightly sheltered areas of coastal Cornwall and Lyme Bay are of low to medium energy. The area with the lowest tidal energy is the Celtic Sea. The bottom waters are well oxygenated throughout the region ( ml Odl; data from ICES). The sediment distribution pattern is irregular and patchy (see British Geological Survey map, 1987). The sedimentary substrates are much influenced by the tidal energy. In the Western Approaches and Western Channel at depths of <1 m the superficial sediments are discontinuous in their distribution and often only a few cm thick (Hamilton et al., 1974). There are no published dates on the ages of the sediments. In theory, they could range in age from a maximum of around 18, years to recent but where the sediment succession is thin, it is assumed that the sediment is mixed so some particles will be old and some young. This is true of almost all shelves where sedimentation is slow. In the deeper parts of the Celtic Sea, where there is a greater thickness of sediments, the surface sediments are almost certainly younger than those of the Channel in the sense that they are unlikely to include the oldest sediment grains. The sediments are not yet in equilibrium with the rapid rise in sea level so readjustment in distribution is still taking place (Stride, 1963). Also, the estuaries are sediment sinks so the shelf is starved of modern terrigenous sediment input. The mobile sea-floor sediments are derived from biogenic material (Boillot, 1965; Channon & Hamilton, 1975, 1976) and reworked Quaternary and older detrital sediments (Hamilton et al., 198). Velocity gradient measurements and grain size analyses were made by Hamilton et al. (198) at 3 stations that are close to samples discussed in this paper (see Table 2). The authors noted that their measured velocity values were not necessarily the

3 Do shelf assemblages leave worthwhile information after dissolution? W s"w B W 7"W B W 5"W 4"W 3"W 2 W 51 N SO Western Approaches. Western Channel 49 N _.. Figure 2. Map of the 6 sampling areas. Each area is denoted with a letter used in Figures 4 and 5. The bathymetric contours are at 8 and 1 m. maximum values experienced at the stations. In the Western Channel, sample B1966 is regarded as typical of the sediment in the area. They considered that the high level of sorting suggested that the sediments may be in equilibrium with the sorting agents. The sands form ripples which migrate over a pavement of shells and pebbles (illustrated in Hamilton et al., 198, plate I, fig. 1). In the Celtic Sea, their stations B2239 and B2245 were described as muddy sediments with a high carbonate content and with a dense infauna. These sediments lie between the relict banks made of clean sands which rise up to 5 m above the adjacent sea floor. The infauna produces sediment mounds which makes the sea floor rough (illustrated in Hamilton et al., 198, plate I, fig. 4). MATERIAL AND METHODS The 54 samples used in this study were selected from a suite of surface (-1 cm) samples previously studied for living and dead assemblages. The methods of collection and processing have previously been described and are only briefly summarised here: samples (Murray, 197), (Murray, 1979), (Murray, 1986). These were collected either with a Shipek grab or with a specially designed sampler (Murray & Murray, 1987). The foraminifera in the >76 Jlm fraction of samples and >63 Jlm fraction of the remainder of the samples had previously been concentrated by heavy liquid flotation in carbon tetrachloride for the former and trichloroethylene for the latter. For this study, a part or all of the flotation was digested in acetic acid (ph 3) for at least 24 hours to remove the calcareous material. Where possible, an assemblage of at least 25 dead agglutinated individuals was picked from each sample but some were too small to give this number (see Appendix 2). We call these acid-treated assemblages (ATA; Alve & Murray, 1994). Thus, for each sample we distinguish two assemblages, one ada (data already available from the publications listed above) and one AT A. With the exception of three AT A samples yielding fewer than 5 individuals, species diversity was calculated for samples with 5 individuals using the information function H(S) (Shannon & Weaver, 1963) and for those with 1 individuals using the Fisher alpha index (Fisher et al., 1943). The ada and ATA faunas have been defined by non-metric multidimensional scaling analyses (MDS ordination; Shepard, 1962; Kruskal, 1964a,b) by use of the PRIMER (Plymouth Routines In Multivariate Ecological Research) package (Clarke & Warwick, 1994). This is a statistical method of determining the similarities between samples and the results are plotted in two dimensions. The similarity matrix was calculated using the Bray-Curtis similarity coefficient (Bray & Curtis, 1957), without transformation of the data as this gave the lowest stress factors. Samples having similar characteristics plot close to one another. The reliability of the results is shown by a stress value which ideally should be <.1 but values of <.2 still give a potentially useful two-dimensional picture. Most of the common organic cemented species are illustrated in Plates 1 and 2. RESULTS Agglutinated taxa are common in most of the ada samples examined in this study but it is important to

4 314 J.W. Murray & E. Alve Table 1. Summary of environmental parameters based on Lee & Ramster (1981), except for the sediment data (British Geological Survey, 1987, plus Murray, unpublished data). Lee & Ramster (1981) plus ICES data for Area Winter Summer Autumn Winter Summer letter Area Bot. T. C Bot. T. C Bot. T. C Bot. Sal. % Bot. Sal. % A Approaches to Bristol Channel B Celtic Sea C Western Approaches D Western Channel E Cornwall - coast F Lyme Bay BGS map + own information Lee & Ramster (1981) plus ICES data for Max. tidal Max. tidal 5 year Area current knots current cm/sec wave height Summer letter Sediment Depth m Spring Spring m thermocl. a sand some b f-m sand + some mud <1 < yes c f-m sand yes d biogenic sand and gravel yes e sand yes f muddy sand and gravel 3-54 <1->1 <5->5 2 none Table 2. Velocity gradient measurements and grain size analyses at 3 stations close to samples discussed in this paper. From Hamilton et al. (198). Station Lat. N 49 27' 5 25' 5 2' Long. W 5 ' r 2' 8 1' Md () Mz () Sorting Mud % Carbonate % Depth m maximum current U1 cm sec friction velocity U* cm sec roughness boundary length shear Zo stress cm N m edform ripples ripples ripples Setting flat floor flat floor interbank make a distinction between those which have a calcareous and those which have an organic cement, as the latter are the only ones which will remain after acid treatment. Calcareous cemented agglutinated taxa are common in the ODAs at water depths >4 m. They make up 1% in 42 of the 54 samples but a particularly high relative abundance is found in nine samples at m water depth where they make up >4% (maximum 74%) of the ODAs (Appendix I, Figure 3). On the other hand, the organic cemented agglutinated taxa are never common and they make up only ;:::,5% in 38 and ;:::,1 % in 13 of the 54 samples (Appendix 2). The ATA data set comprises a total of at least 45 organic cemented species (many are unidentified scaly trochamminids) but only the common ones are included in Appendix 2. The MDS defined six ODA faunas which coincide with the six geographical areas from which they were collected (Figure 4). The inner shelf assemblages (from areas a, e, and f), are separated into three distinct faunas whereas the outer shelf ones (from areas b-d) plot closer together and show a higher degree of similarity. The ATAs show the opposite pattern with the inner shelf ATAs forming one fauna, whereas the three outer shelf areas each have separate faunas. We have distinguished epifaunal attached and clinging taxa in both the ODAs and the ATAs (Table 3). By attached we mean species that are fixed in one position and immobile, in contrast to clinging, which implies that the individuals hold on to the substrate by their pseudopodia and are mobile. Attached forms typically have a flattened apertural face whereas clinging forms do not necessarily have this form. There are 12 ODA and 6 ATA attached! clinging species. Additionally, the scaly trochamminids include several different species so the total number of attached!clinging ATA taxa is probably much the same as for the ODAs. The inner shelf areas (a, e, and ) have low to moderately high abundances (generally <5%) of attached! clinging forms in both the ODAs and the AT As (Figure 5, top). In two of the outer shelf areas, the Western Approaches and the Western Channel (areas c and d

5 Do shelf assemblages leave worthwhile information after dissolution? 315 Table 3. Attached/ clinging forms with references to sources. ODA Organic cemented agglutinated Cribrostomoides jeffreysii Cribrostomoides sp. Lepidotrochammina ochracea Portatrochammina murrayi Calcareous agglutinated Gaudryina rudis Textularia sagittula/truncata ATA Organic cemented agglutinated Cribrostomoides jeffreysii Cribrostomoides sp. A Deuterammina (D.) rotaliformis Portatrochammina murrayi Tritaxis britannica Tritaxis fusca Trochamminids (scaly) Calcareous Asterigerinata mamilla Cibicides lobatulus Gavelinopsis praegeri Planorbulina mediterranensis Rosalina anomala SpiriUina vivipara Attached = fixed, immobile Cibicides lobatul us Planorbulina mediterranensis Rosalina anomala Tritaxis fusca Clinging = mobile Asterigerinata mamilla Cribrostomoides jeffreysii Gave/inopsis praegeri Spirillina vlvzpara Textularia truncata Nyholm, 1961; Dobson & Haynes, 1973 Kitazato, 1988 Dobson & Haynes, 1973 (clinging, Sturrock & Murray, 1988) Bronnimann & Whittaker, 1984 Dobson & Haynes, 1973 Dobson & Haynes, 1973 Sturrock & Murray, 1981 Sturrock & Murray, 1981; Kitazato, 1988 Haward & Haynes, 1976 respectively), and in the northern part of the Celtic Sea (area b), the attached/clinging forms make up >5%. Maximum values are present in the Western Channel and northern Celtic Sea. Overall, there is a significant positive correlation (r =.66, P <.1) between the relative abundance of the attached/ clinging taxa in the ATAs and ODAs (Figure 5, bottom). Two species of Eggerelloides have been distinguished. Eggerelloides medius is confined to water depths greater than around 9 m (Figure 6, top) but it occurs mainly where there is some mud in the sediments and is absent from comparable depths in the Western Channel where mud is virtually absent. Eggerelloides scaber is present from shallow waters to 15 m but is most abundant at depths of less than around 9 m (Figure 6, top). Portatrochammina murrayi occurs in all areas but is common only at >8 m water depth (Figure 6, middle). Adercotryma wrighti is abundant in the muddy sands of the Celtic Sea and absent from the clean sands of the Western Channel and coastal areas (Figure 6, middle). We have separated two species of Cribrostomoides and these have different distributions. Cribrostomoides jeffreysii is abundant over a broad depth range and is a major component in a number of ATA samples from all areas except the Approaches to the Bristol Channel (Figure 6, bottom). On the other hand, Cribrostomoides sp. A is confined to depths greater than around 8 m and is abundant only in the northern, shallower part of the Celtic Sea and in the Western Approaches (Figure 6, bottom).

6 316 J.W. Murray & E. Alve.s.c li (j) "..l!l til :s: , <> o.. It> 4 t 6 _ 8 '.$.o 1 I -.<> 12 e!o <b It. 14' <b % I Calcareous cementedl Q Organic cemented 16L Figure 3. Relative abundance of calcareous cemented and organic cemented agglutinated taxa in the ODAs plotted against water depth. Alpha index 3r r =.856 n = = new data x {g 2 c til "E «5 o o ODA, alpha index H S) '---' , r.665 bathyal-abyssal n = = new data 2.5 (j) ]:,2. ci I- 1.5 «1..5 _' o., \ \ Cb / <9Shelf. ' ' ODA, H(S) % o o 2 4 Iso a.. {g 8. Q) , C r= n = 54 8 ;:: 6 «en c o Att.lcling. ODA (%) Figure 5. Top: depth distribution (relative abundance) of attached/clinging taxa in ODAs and ATAs. The lower case letters refer to the sampling areas (shown on Figure 2). Bottom: Linear correlation between relative abundance of attached/clinging taxa in ODAs and ATAs. ClIneata arctica is restricted to depths <1 m (Figure 7) and is abundant only in the three inner shelf areas (a, e, and f, Figure 2). Haplophragmoides bradyi occurs in all samples from the Celtic Sea (except one) but is absent from all the other areas. Recllrvoides trochaminiforme basically occurs in the Approaches to the Bristol Channel, the Celtic Sea, and the Western Approaches. Both species are abundant only at >9 m water depth (Figure 7). Figure 4. MDS plots. Top: ODA and Bottom: ATA. Each lower case letter represents a sample and the different letters indicate the geographic areas whence the samples were collected (shown on FIgure 2).

7 Do shelf assemblages leave worthwhile information after dissolution? 317 low 9'W 8W r w 6W 5W 4W 3W 2W Eggerelloldes medius Eggerelloides scaber t o. ]>3% 51"N. <3%. eo SO"N o ' 49"N O. n [ I. '.. D II 49"N li. [ J o Crlbrosllomold-.J >1% 51"N <1% SO"N '. I f 49"N Figure 6" Geographical and depth (inset graph) distributions of selected organic cemented agglutinated species in the AT As" Top: Eggerelloides medius and E" scaber" MIddle: Portatrochammina mllrrayi and Adercotryma wrighti" Bottom: Cribrostomoides jeffreysii and Cribrostomoides sp" A. The bathymetric contours are at 8 and 1 m" Where a species is absent the sample point has been omitted from the map"

8 318 J.W. Murray & E. Alve DO 4 IP D Ql - E 6 '-'..c -a. rb 8 Ib Q). X X D td< >s< CU1 U Xx l.x x 12 XX.1II x x. 14 X x 16 x D DC. arctica H. bradyi x R. trochamminiforme Figure 7. Depth distribution (relative abundance) of Cuneata arctica, Haplophragmoides bradyi, and Recurvoides trochamminifonne. The diversity values for the ODAs (alpha index ; H(S) ) are always higher than those of the ATAs (alpha index.9-7.; H(S) ). There is no correlation between the H(S) values but there is a weak but significant correlation (r =.32, P <.5) between the alpha values, and the distributional trends show the same pattern with minimum values around 8 m water depth (Figure 8, Appendix 1 and 2). The new diversity data have been plotted together with previously published data (Figure 9). There is a moderate overlap between environmental fields in the alpha-diagram and a higher overlap between fields in the H(S) diagram. DISCUSSION It is well established that 1) the distribution and faunal characteristics of benthic foraminiferal assemblages are determined by the prevailing environmental conditions and 2) most foraminiferal assemblages in modern marine environments, except intertidal marshes and the deep sea below the ceo, generally are strongly dominated by calcareous taxa. Based on these facts, we want to address the following question: Is the ecologically controlled distributional pattern and community structure seen in modern calcareous dominated assemblages also reflected in the organic cemented agglutinated taxa even when they only make up a very subordinate part of the original assemblages? The answer to this question is of fundamental importance for interpreting fossil agglutinated assemblages. If the answer is no, fossil agglutinated assemblages formed as a residue after carbonate dissolution of Alpha index g ij 6.c - a. Q) o. 8 f» "C. f Q) o 8 - ('i :.. oo 12.. o 14,.ATA ooda 16 H(S) COo E - 6.c. Q) -a 8 soc o Q) o o 1.: ooo ".4) 12. ". 14 I. 16 ATA ooda Figure 8. Species diversity plotted against water depth. Top: Fisher alpha. Bottom: information function. original calcareous assemblages are not likely to be ecologically meaningful. On the other hand, if the answer is yes, it certainly opens the possibility that many fossil agglutinated assemblages represent the end product left after dissolution. It will also add a new perspective to palaeoecological studies of benthic foraminiferal assemblages in that interpretations can be carried out solely on the agglutinated taxa if there is reason to assume that parts of the calcareous assemblages have been (selectively) dissolved.

9 Do shelf assemblages leave worthwhile information after dissolution? 319 Lymoe Bay f f f : b b f f f offcornwall J e aa Ab bb a a b" bb Western.;; """ O Channel :' ODA, no transformation stress =.15 b bb b b:bbb b b b Bristol a,b Channel \ Western Bristol Channel off Cornwall Lyme Bay f Western ChanneG:Y dd d a b Approaches Celtic Sea ATA, no transformation stress =.12 Celtic Sea Figure 9. Summary diagrams for diversity. The new data are plotted in the shaded field delimited by the dashed line. The other fields are based on data in Alve & Murray (1994; 1995), Murray & Alve (1994; 1999a,b). Although many of the ODAs presented here have a high proportion of agglutinated tests (Figure 3), only those with an organic cement (which make up 5% in most ODAs) will remain to make up the ATAs after carbonate dissolution. The following discussion focuses on a comparison between the ecological features of the ODAs and ATAs. In addition to this ecological aspect, we also discuss some aspects of the fact that certain fossil, basically agglutinated, assemblages contain some calcareous microfossils and/ or macrofossils. This is used by several authors as an argument to prove that their assemblages have not been subject to carbonate dissolution. Assemblages There is some overlap in water depth and also considerable overlap in environmental parameters such as temperature and salinity between the six geographic areas and all, except the Celtic Sea, have sand-dominated substrates. Despite these overlaps and the fact that some of the ODA species are common to several areas (e.g., Textularia sagittula and Cibicides lobatulus), the MDS plots show that each inner shelf area (a, e, and f) has a unique ODA fauna. However, the ATA faunas for the inner shelf plot as one field because they are all dominated by a single species (Eggerelloides scaber). This implies that the calcareous taxa in the ODAs are better discriminators of these shallower areas than are the agglutinated taxa. A similar situation is present in the shallow waters of the Skagerrak/Kattegat (eastern North Sea) where a single Miliammina fusca dominated ATA replaces 1 different ODAs (Murray & Alve, 1999a). Nevertheless, even here it is possible to distinguish between these shallow water environments if the whole assemblage is considered rather than just the predominant species. The fact that the faunal composition of the ODAs and ATAs from the outer shelf areas (b-d, Figure 4) each define three different faunas, characteristic of the same three geographical areas, shows that the assemblage structures of the ODAs are reasonably well preserved in the ATAs. A comparable pattern was found in the Skagerrak, eastern North Sea, where the main faunal boundaries between ODAs (faunas defined based on the most common 1-2 species) were reflected in the ATAs (Alve & Murray, 1995). We think the similarity in faunal distributional patterns for the ODAs and ATAs is really remarkable because it means that the ATA, which is only a small sub-assemblage of the whole original assemblage, still holds as much ecological information. In other words, the faunal characteristics of samples that cause them to be be grouped together are faithfully preserved in the ATAs. This is a very significant conclusion. A comparable trend has recently been reported for metazoans. In order to test if only a small part of the data set provides information comparable with the original data set, Somerfield & Clarke (1995) reexamined data on nematodes and macrofauna from two areas. They found that whereas nematode data aggregated to generic level provided results comparable with those at species level, aggregation into higher taxonomic units led to loss of resolution. For the macrofauna, aggregation to higher taxnomic levels, even to phylum level, gave adequate results. The nematode pattern may be analogous to using ATAs instead of ODAs in benthic foraminiferal studies. ada attached/clinging High abundances of attached and clinging forms are often associated with moderate to high energy environments (e.g., Sturrock & Murray, 1981; Schonfeld, 1997; Peebles et al., 1997) where they live on pebbles, shells, algae, hydroids and other structures which project above the sediment surface (e.g., Dobson & Haynes, 1973; Lipps, 1983; Freiwald,

10 32 J.W. Murray & E. Alve 1995). In the present study area, both the attached immobile and the clinging mobile forms are represented by taxa with calcareous tests as well as organic cemented agglutinated tests (Table 3). Furthermore, there is a significant positive correlation between the relative abundance of attached/ clinging forms in the ODAs and ATAs (Figure 5). It is reasonable to assume that the taxa with these modes of life also reflect similar or related trophic strategies, irrespectively of their test wall construction material. If this is the case, it means that they also playa related role in the community structure. Consequently, it seems that the environmental characteristics reflected by the occurrence and distribution of attached and clinging forms in the ODAs are similarly reflected in the ATAs. Diversity "The commonest-used measure of community structure is the diversity of a community" (Gray, 1974) and in the foraminiferal literature the Fisher alpha index and the information function are most commonly used (Murray, 1991, pp. 3 and 319). In our previous comparative studies of ODAs and ATAs from other areas, we have concluded that the information function does not seem to discriminate between environments as well as the Fisher alpha index does. This certainly is the case for the new data set from off SW England too as there is no correlation between the two data sets for the H(S), while a low but significant positive correlation exists for the alpha index. However, when plotted together with our previous results from marginal marine to abyssal environments, the correlation improves dramatically for both diversity indices (Figure 9) but the correlation is still stronger for the alpha index than for the H(S). The new H(S) results partly overlie the fields previously defined for shelf seas including shelf basin and fjords and they also show considerable overlap with both marginal marine and bathyal! abyssal fields. On the other hand, the alpha values not only show a very clear pattern of increasing diversity from marginal marine to abyssal environments but also a much clearer separation between fields. Consequently, the new results show that the community structure in the ODA, as described by the faunal diversity, is reasonably well preserved in the AT A. Furthmore, they confirm very clearly our previous conclusion that the alpha index is the better discriminator between environments. Apparent depth related boundary at -8-1 m The six sampling areas show some overlap in bathymetry (Table 1) yet some of the faunal data appear to show a boundary between 8 and 1 m. In the ODAs the percentage of calcareous cemented agglutinated tests peaks at this depth (Figure 3), both the ODAs and AT As show a separation between inner and outer shelf faunas (Figure 4, areas a, e, f and b, c, d respectively), there is a low in the attached/ clinging abundances at around 8 m (Figure 5) and likewise in the diversity (Figure 8). In the ATAs, E. medius, A. wrighti, P. murrayi, Cribrostomoides sp. A, H. bradyi and R. trochamminiforme are restricted to depths >8-1 m whereas E. scaber and C. arctica are abundant only at depths shallower than this (Figures 6, 7). However, closer examination of the data suggests that the pattern may be apparent rather than real. The main area contributing data to the 8-1 m depth zone is area a, the Approaches to the Bristol Channel. Here the substrate is mobile sand due to the powerful tidal currents (speeds of up to 2 cm/sec in an area of sand waves, Stride, 1982, p. 68), and it generally lacks larger fragments of shells. Therefore, it does not provide suitable substrates for attached/clinging taxa (hence the absence of calcareous agglutinated taxa in the ODA). This is a highly stressed environment so the species diversity is low. At comparable depths in areas band d, shell fragments are present, and both attached/clinging and calcareous agglutinated taxa are common. Hamilton et al. (198) noted that in the Western Channel (area d), the sand-sized sediment grains are entrained on both the flood and ebb tides. Although areas c and d are still subject to some sediment mobility, they are less stressed than area a. Each MDS plot shows 4 major faunal groupings but they have different geographic distributions from ODA to ATA (ODA: a, e, f, and b, c, d combined; ATA: b, c, d, and a, e, f combined). Adercotryma wrighti and E. medius are not uniformly common throughout areas b, c and d; they are both common in area b where the substrate contains some mud and often absent at comparable depths in areas c and d. Thus, in summary, it may be concluded that if area a had not been included in the study, the distribution patterns would show a progression from inner to outer shelf. Consequently, this represents a nice example of how a seemingly clear faunal depth distribution is only apparent (due to the vagaries of sample distribution) rather than real (due to ecological differences). Comments on dissolution Despite the fact that some or many fossil agglutinated assemblages might be the result of dissolution, most authors still consider the lack of calcareous forms to be primary. This is frequently because the samples contain some calcareous microfossils or macrofossils. However, unless there has been 1% dissolution of calcareous material, the presence of some calcareous tests is to be expected. For example, Hald & Steinsund (1996) found that in the surface sediments of the Barents and Kara seas, the abundance of calcareous tests could be related to the relative corrosivity of the bottom waters. Dissolution is known to be selective between species (although this was disputed by Wefer & Lutze, 1978), and between different taxonomic groups including planktonic and

11 Do shelf assemblages leave worthwhile information after dissolution? 321 benthic foraminifera (see the classic papers in Sliter et ai., 1975). Carbonate minerals have been described as 'among the most chemically reactive common minerals under Earth surface conditions' (Morse & Mackenzie, 199). In aqueous solutions, the degree of disequilibrium (under saturation or supersaturation) is a primary control on the rate of reaction. There may be partial selective dissolution which removes certain components and leaves others untouched. The rate and amount of dissolution that takes place depends on a plexus of factors which include the mineralogy (aragonite, low or high magnesian calcite), any structural disorder within the crystal components, the overall size of the object, and the microstructure of the biogenic material whether or not material has been adsorbed onto the grain surfaces, and the complex chemistry of the surrounding seawater (e.g., including the inhibiting effects of magnesium ions). Dissolution is likely to be more active in open systems (such as in seawater or in sediment that is well flushed by bioturbating organisms) because the dissolved material is removed and undersaturation can be maintained. It is less active in closed systems (such as stagnant bottom waters or sediments lacking bioturbators) because after initial dissolution the waters may become saturated with respect to calcium carbonate and dissolution will cease (as in the western part of Long Island Sound, USA, Green et al.,1993).thus some calcareous material may be locally present even when severe dissolution has affected much of a sequence. Where dissolution takes place in sediment pore waters, heterogeneity due to varying local intensity of bioturbation may cause some parts to undergo more active dissolution than others. Under such conditions, calcareous microfossils are more likely to be well preserved within large calcareous macrofossils than in the surrounding sediment. Also, some tests can bypass the zone of active dissolution (just beneath the sediment surface) by being transported downwards by deeper bioturbators (Green et ai., 1993). Relicts of calcareous tests The Celtic Sea and the English Channel are sites of modern glauconite/ glaucony formation. The mineral fills the cavities of foraminiferal tests, the stereom of echinoderms and microborings in shells (Dangeard, 1928; Murray, 1965; George & Murray, 1977). Many of the shelf ATAs include glauconitic internal moulds especially of the calcareous agglutinated Textularia sagittula group. The presence of internal moulds in natural assemblages provides firm evidence that dissolution has taken place. Comparison with modern examples From the work of several authors (e.g., Murray, 1989; Culver et al., 1996, and references therein), it is known that natural dissolution is taking place today, especially in intertidal areas and we have recorded it as an important process in both the shallow waters of the Skagerrak and Kattegat, eastern North Sea, (Murray & Alve, 1999b) and in the deep Skagerrak Basin (Alve & Murray, 1995; 1997). No exclusively agglutinated assemblages have been described from temperate shelf seas. However, in polar seas, carbonate dissolution seems more active and there are assemblages composed largely of agglutinated taxa. For example, Corner et ai. (1996) presented data on living and total assemblages from a delta and adjacent fjord at Tana, northern Norway. The delta slope and basin sandy sediments from m and m water depth have 73-98% and 86-93% agglutinated tests in the dead assemblages and the dominant taxa are Adercotryma glomera tum (4 chambers in the final whorl) and Spiroplectammina biformis. The environment is fjordic with bottom salinities of 33-34% and temperatures of 2-8 D C so it is rather different from that of this area. In the Barents Sea the occurrence of the Reophax assemblage at depths of around 25-3 m was attributed to carbonate dissolution in the mixing zone between Atlantic and Arctic waters (Hald & Steinsund, 1992). Likewise, Schafer & Cole (1986) attributed the high dominance of agglutinated taxa (especially Textularia earlandi and Spiroplectammina biformis) in fjords off Baffin Island, Arctic Canada, to the presence of Arctic bottom water, but apart from being cold this must also be corrossive to carbonate. In addition to these more or less syndepositional taphonomic changes, it is also necessary to keep in mind diagenetic dissolution at various stages throughout the history of the fossil assemblages. Fossil examples of dissolution of originally calcareous assemblages Even though most authors consider the lack of calcareous forms to be primary, others have interpreted their agglutinated assemblages to be a result of dissolution of originally partly calcareous assemblages. In the Cretaceous of Colombia there are low diversity, high dominance assemblages of Ammobaculites and Haplophragmoides in muddy sediments interpreted as inner to outer shelf deposits which formed under high terrigenous influx in waters undersaturated with calcium carbonate during times of maximum flooding (Vergara et al., 1997). Therefore, even if calcareous forms originally lived in the area they have not been preserved. In a mudrock sequence spanning the late Palaeocene - early Eocene, Laursen & Andersen (1997) distinguished three agglutinated interval zones sandwiched between two zones also containing calcareous forms. They attributed the faunal succession to changes in the bottom waters and the agglutinated assemblages were thought to represent periods of slight acidity although in the case of their assemblage 2B it was thought that some secondary

12 322 }.W. Murray & E. Alve dissolution had taken place. They considered an assemblage of Glomospira and Haplaphragmoides to represent outer shelf, and Evolutinella and Verneuilinoides as mid-shelf. The Boom Formation (Early Oligocene) in Northern Belgium is a clay succession. The lower 35 m are calcareous and contain assemblages which are predominantly calcareous but the top 3 m have been decalcified and yield only organic cemented agglutinated foraminifera. However, the agglutinated forms are the same throughout the succession so Hooyberghs and Moorkens (pers. comm., 1997) concluded that the differences are due to preservation with acidic waters affecting the upper part. In all these cases the substrates were fine grained and the assemblages differ somewhat in faunal composition from those descibed in the present study. However, they demonstrate that the process of natural carbonate dissolution forms analogous agglutinated assemblages. Calcareous foraminifera can also be destroyed to leave an organic cemented agglutinated assemblage in carbonate rocks. Wightman (199) noted that the organic cemented genus Haplaphragmoides was the only common form in Lower Cretaceous dolomitic limestones in Portugal. He suggested that the calcareous forms had been destroyed during dolomitisation. A test for dissolution in the fossil record In certain stratigraphic successions there is a faunal change, either laterally or vertically, from predominantly calcareous to predominantly or entirely organic cemented agglutinated assemblages. In order to assess whether the organic agglutinated assemblage is the residue from the dissolution of an original calcareous assemblage it is possible to carry out a simple test. Take the >63 mm fraction from one or more calcareous samples, place it in weak acid (e.g., acetic acid ph 2.5) until all the carbonate material has been dissolved. Compare the residue with the the agglutinated components in the otherwise calcareous dominated assemblages. Their similarity or dissimilarity will be a guide as to whether or not dissolution has occurred naturally. Of course, in circumstances where there has been an environmental change such as a from subtidal to marsh, the agglutinated assemblages will be different anyway. In order to test this, Hooyberghs and Moorkens provided two samples from the calcareous Tergagen Member of the Early Oligocene Boom Formation. These were processed in the normal way to give the ODA and part of this was then treated with acetic acid ph 2.5 to give the ATA. Sample R7 had an ODA with 93% calcareous foraminifera (Fisher alpha 1.5, H(S) 2.75) and this yielded an ATA (Fisher alpha 1.4, H(S).6). Sample R9 had an ODA with 86% calcareous foraminifera (Fisher alpha II, H(S) 3.) and this yielded an AT A (Fisher alpha 1., H(S).3). The principal ATA species in both was Spiroplectammina carinata which was corroded, infilled with pyrite, and poorly preserved. The ODAs are clearly from a shelf environment (from the high alpha and H(S) values and from the abundance of planktonic tests: 15-16%). The ATA for R7 plots on the margin and R9 close to the field for shelf seas on the alpha diagram while both plot outside but close to the field for shelf seas on the H(S) diagram (Figure 9). This is a clear demonstration that exclusively agglutinated assemblages can be obtained from original predominantly calcareous fossil assemblages. CONCLUSIONS The key question posed in this paper is: do the ODAs, which contain the whole data set, and the ATAs, which represent only small subsets of the original data, have comparable faunal structures? We can confidently say yes for the following reasons: 1. The MDS plots have defined 3 ODA and 3 ATA faunas (former less clearly defined than the latter) for the outer shelf, and each ODA/ ATA pair is characteristic of the same 3 geographical areas. For the inner shelf, 3 distinct ODA faunas are defined (one per geographic area), whereas the ATAs plot together in one faunal field. This reflects that the faunal characteristics of the ODAs, which cause them to be grouped together in distinct faunas, are generallly well preserved in the ATAs. However, the ATAs seem to be better discriminators between outer shelf environments whereas the ODAs are better discriminators for those of the inner shelf. 2. There is a significant positive correlation in the distribution and relative abundance of attached and clinging taxa between the ODAs and ATAs. 3. There is a low, but significant positive correlation between the alpha diversity index in the ODAs and ATAs. An important conclusion is that even if the proportion of organic cemented agglutinated tests in the ODAs is only a few percent, when these are concentrated as ATAs they reveal ecological information comparable with that of the ODAs. To put this in a broader context, we have recalculated the correlation between the diversities of the ODAs and AT As for our previously published data to also include the new data presented here. The result is a significant, positive correlation, particularly for the alpha index, with a clear pattern of increasing diversity from marginal marine to abyssal environments. Consequently, we believe that a faunal structural relationship exists between the ODAs and ATAs of all the samples we have studied so far. In addition, this kind of study is important as it provides information on the relative abundance and distribution of agglutinated taxa which are normally too rare to be properly studied in calcareousdominated recent assemblages.

13 Do shelf assemblages leave worthwhile information after dissolution? 323 For fossil assemblages, it is now possible to confidently state that useful ecological information can be obtained by analysing just the organic cemented agglutinated assemblages in those cases where there is reason to believe that parts of the calcareous components have been selectively dissolved. The major conclusion is that organic cemented agglutinated foraminifera, which make up only a small part of the overall foraminiferal community, still record the major attributes of the environments. This is a remarkable and important conclusion which has great relevance for interpreting palaeoecology. ACKNOWLEDGEMENTS First of all, we want to express a sincere thank you to John E. Whittaker for help with the taxonomy. We also thank Dr A Tabor, British Oceanographic Data Centre, for help in obtaining oceanographic data from ICES, Bob Whitmarsh and Peter Hunter (SOC, Challenger Division) for advice on the preparation of maps using Gmt, and Barry Marsh and Geir Holm for printing SEM photographs. The study was partly funded by NERC Small Grant GR9/2282. REFERENCES Alve, E., & Murray, J.W Experimet to determine th.e origin and p':lleoenvironmental sigmficanc of gglutinated foramimferal assemblages. In: KamIIskI, M.A, Geroch, S., & Gasinski, M.A., (eds), Proceedmgs of the Fourth International Workshop on gglutna!ed Foraminifera. Grzybowski FoundatIOn Special PublicatIOn, 3, I-II. Alve, E., & Murray, J.W High benthic fertility and taphonomy of foraminifera: a case study of the Skagerrak, North Sea. Marine Micropaleontology, 31, Alve, E., & Murray, J.W Marginal marine environments of the Skagerrak and Kattegat: a baseline study of living (stained) benthic foraminiferal ecology. Palaeogeography, Palaeoecology, Palaeoclimatology, 146, Boillot, G Organogenic gradients in the study of neritic deposits of biological origin: the example of the western English Channel: Marine Geology, 3, " Bouysse P., Horn, R, Lapierre, F., & Le Lann, F Etude des grnds bancs de sable du sud-est de la mer Celtique. Manne Geology, 2, Bray, J.R, & Curtis, J.T An ordation?f the uplnd forest communities of Southern Wisconsm. Ecological Monographs, 27, British Geological Survey Sea bed sediments around the United Kingdom (South sheet). Bronnimann, P., & Whittaker, J.E !- revision of the foraminiferal genus Adercotryma Loebhch and Tappan, with a description of A. wrighti sp. nov. from Bntish waters. Bulletzn of the British Museum of Natural History (Zoology), 52, Channon, RD., & Hamilton, D.H.,1975. Wave and tidal-current sorting of shelf sediments southwest. of England. Philosophical Transactions of the Royal Society, London, 1279, Channon, RD., & Hamilton, D.H.,1976. Wave and tidal-current sorting of shelf sediments southwest of England. Sedimentology, 23, Chaster, G.W., Report upon the Foraminifera of the Southport Society of Natural Science District. First Report of the Southport Society for Natural Science, (189-91), Clarke, K.R, & Warwick, RM Changes in arine communities: an approach to statistical analysis and interpretation. Natural Environment Research Council, UK,144pp. Corner, G.D., Steinsund, P.I., & Aspeli, R 199. Dstribution of recent benthic foraminifera in a subarctic fjord-delta: Tana, Norway. Marine Geology, 134, Culver, S.J., Woo, H., Oertel, G.F.!.& Buzas,!vI.A Foraminifera of coastal depositional envlroni?ents, Virginia, U.S.A: distribution and taxonomy. PalalOs, 11, Dangeard, L Observation de geologie sous-marie et d'oceanographie relatives a la Manche. Annales Institute Oceanographlque, NS 6, Dobson, M., & Haynes, J Associaon of foraminifera with hydro ids on the deep shelf. Micropaleontology, 19, Fisher, RA, Corbet, AS., & Williams, C.B The relationship between the number of species ru:d the numbe.r of individuals in a random sample of an ammal population. Journal of Animal Ecology, 12, Freiwald, A Bacteria-induced carbonate degradaon: a taphonomic case study of Cibicides lobatulus from a high Boreal carbonate setting. Palaios, 1, George, M., & Murray, J.W Glauconite in Celtic Sea sediments. Proceedings of the Ussher Society, 4, 94-1I. Gray, J.S Animal-sediment relatir:tships. Oceanography and Marine Biology Annual ReView, 12, Green, M.A, Aller, RC., & Aller, J.Y <;:a.rbonte dissolution and temporal abundances of forammlfera m Long Island Sound sediments. Limnology and Oceanography, 38, Hald, M., & Steinsund, P.I Distribution of surface sediment benthic foraminifera in the southwestern Barents Sea. Journal of Foraminiferal Research, 22, Hald, M., & Steinsund, P.I Benthic fora?linifera and carbonat (sic) dissolution in the surface sediments o the Barents and Kara sea. In: Stein, R, Ivanov, G.I., LeVItan, M.A, & Fahl, K. (eds), Surface sediment composition and sedimentary processes in the central A:ctic Oean and along the Eurasian continental margm. Benchte zur Polaiforschung, 212, Hamilton, D.H., Channon, R.D., Griffiths, E.C., & Sommerville, J.H Sediments and tidal energy in the South Western Approaches to Britain an the Seven Estuary. Memoire de I'Institut de Geologie du Basszn d'aquitaine, 7, Hamilton, D.H., Sommerville, J.H., & Stanford, P.N. 9. Bottom currents and shelf sediments, southwest of Bntam. Sedimentary Geology, 26, Haward, J.B., & Haynes, J.R Chlamlls opercularis (Linnaeus) as a mobile substrate for forammifera. Journal of Foramaminiferal Research, 6, Kruskal, J.B. 1964a. Multidimensional scaling by optimizng goodness of fit to a non-metric hypothesis. Psychometnka, 29, Kruskal, J.B. 1964b. Nonmetric multidimensional scaling: a numeric method. Psychometrika, 29, Laursen, G.V., & Andersen, S.B A Late Palaeocene - Early Eocene benthic foraminiferal record from Bolvstrup, Denmark, showing a remarkable agglutinated fauna. Journal of Micropalaeontology, 16, Lipps J.H Biotic interactions in benthic foraminifera. In: Travesz, M.J.S. & McCall, P.L. (eds), Biotic interactions in Recent and Fossil Benthic Communities. Plenum Press, New York, Morse, J.W., & Mackenzie, F.T Geochemistry of sedimentary carbonates. Elsevier, Amsterdam. 77 pp. Murray, J.W On the F?ramnife:ida of th \lymouth region. Journal of the Manne BIOlogical ASSOCiatIOn of the United Kingdom, 45, Murray, J.W Foraminifers of the Western Approaches to the English Channel. Micropaleontology, 16, Murray, J.W Recent er:tthic foraminiferids of the Celtic Sea. Journal of Foramzniferal Research, 9,

14 324 J.W. Murray & E. Alve Murray, J.W Living and dead Holocene foraminifera of Lyme Bay, southern England. Journal of Foraminiferal Research, 16, Murray, J.W Syndepositional dissolution of calcareous foraminifera in modem shallow-water sediments. Marine Micropaleontology, 15, Murray, ).W Ecology and palaeoecology of benthic forammifera. Longman, Harlow, Essex. 397 pp. Murray,.r,w., & Alve, E High diversity agglutinated foramlmferal assemblages from the NE Atlantic: dissolution experiments. Cushman Foundation Special Publication, 32, Murray, J.W., & Alve, E. 1999a. Taphonomic experiments on marginal marine foraminiferal assemblages: how much ecological information is preserved? Palaeogeography, Palaeoecology, Palaeoclimatology, 149, Murray, J.W., & Alve, E. 1999b. Natural dissolution of shallow water benthic foraminifera: a case study of ecology and taphonomy. Palaeogeography, Palaeoecology, Palaeoclimatology, 146, Murray, W.G., & Murray, J.W A device for obtaining representative samples from the sediment water interface. Marine Geology, 76, Peebles, M.W., Hallock, P., & Hine, A.e Benthic foraminiferal assemblages from current- swept carbonate platforms of the norhtern Nicaraguan Rise, Caribbean Sea. Journal of Foraminiferal Researcn, 27, Schafer, e.t., & Cole, F.E Reconnaissance survey of benthonic foraminifera from Baffin Island fjord environments. Arctic, 39, Shannon, e.e., & Weaver, W.W The mathematical theory of communication. University of Illinois Press, Urbana, Shepard, R.N The analysis of proximities: multidimensional scaling with an Ul1known distance function. II. Psychometrika, 27, Schonfeld, J The impact of the Mediterranean Outflow Water (MOW) on benthic foraminiferal assemblages and surface sediments at the southern Portuguese continental margin. Marine Micropaleontology, 29, Sliter, W.V., Be A.W.H., & Berger, W.H (eds) Dissolution of deep sea carbonates. Cushman Foundation Special Publication, 13, Somer field, P.J., & Clarke, K.R Taxonomic levels, in marine community studies, revisited. Marine Ecology Progress Series, 127, Stride, AH Current-swept sea floors near the southern half of Great Britain. Quarterly Journal of the Geological Society, London, 119, Stride, AH. (ed.), Offshore tidal sands: processes and deposits. Chapman and Hall, London. 222 pp. Sturrock, S., & Murray, J.W Comparison of low energy and high energy marine middle shelf foraminiferal faunas; Celtic Sea ancf western English Channel. In: Neale, J.W.. & Brasier, M.D: (eds), Microfossils from Recent and Fossil Shelf Seas. Elhs Horwood Ltd., thichester, Vergara, L., Rodriguez, G., & Martinez, Agglutinated foraminifera and sequence stratigraphy from the Chipaque Formation (Upper Cretaceous) of EI Cruero section, Colombia, South America. Micropaleontology, 43, Wefer, G., & Lutze, G.F Carbonate production by benthic foraminifera and accumulation in the western Baltic. Limnology and Oceanography, 23, Wightman, W.e Estuarine and marsh foraminifera from the lower Cretaceous of the Lusitanian Basin, West Portugal. In: Hemleben, e., Kaminski, M.A, Kuhnt, W., & Scott, D.B. (eds), Paleoecology, biostratigraphy, J?aleoceanography and taxonomy of agglutinated foraminifera. Kluwer, Amsterdam, TAXONOMIC COMMENTS Adercotryma wrighti (Plate 1, Figs 1, 2). Bronnimann & Whittaker (1987) distinguished between A. glomeratum (4 chambers in the final whorl, 3 visible on each side) and A. wrighti (3 chambers in the final whorl, 3 seen on the apertural and 2 on the antapertural side). In the original paper on the Celtic Sea Murray (1979) referred them to A. glomerata because A. wrighti had not yet been named. Cribrostomoides sp. A (Plate 1, Figs 9-12). This species resembles C. jeffreysii (Plate 1, Figs. 5-7) but the wall is thinner, smoother, and shiny in appearance. These have been included in C. jeffreysii in previous papers by both authors. This separation is justified by the different distribution patterns as seen in the present study. Cuneata arctica (Plate 1, Figs 13, 14). Previous studies from this area have termed this form Clavulina obscura Chaster. According to Chaster (1892), C. obscura has a triserial initial part which develops into a uniserial growth. We have not been able to see a triserial growth pattern in our specimens. Eggerelloides scaber (Plate 2, Figs 14, 15) and Eggerelloides medius (Plate 2, Figs 16, 17). In previous studies of the living and dead assemblages from the study area, Eggerelloides scaber (as E. scabrus) also included Eggerelloides medius but in this study we have separated them ,

15 Do shelf assemblages leave worthwhile information after dissolution? 325 FAUNAL LIST OF AGGLUTINATED TAXA Adercotryma glomeratum (Brady) = Lituola glomerata Brady, 1878 Adercotryma wrighti Bronnimann and Whittaker, 1987 Ammobaculites filiformis (Earland) = Ammobaculites agglutinans var. filiformis Earland, 1934 Ammoscalaria pseudospiralis (Williamson) = Proteonina pselldospiralis Williamson, 1858 Ammoscalaria runiana (Heron-Allen and Earland) = Haplophragmium runianum Heron-Allen & Earland, 1916 Cribrostomoides jeffreysii (Williamson) = Nonionina jeffreysii Williamson, 1858 Cuneata arctica (Brady) = Reophax arctica Brady, 1881 Deuterammina (Deuterammina) rotaliformis (Heron-Allen & Earland) = Trochammina rotaliformis Heron Allen & Earland, 1911 Eggerella europeum (Christiansen) = Verneuilina europeum Christiansen, 1958, new name for Verneuilina advena Cushman of Hoglund, 1947 Eggerelloides medius (Hoglund) = Verneuilina media Hoglund, 1947 Eggerelloides scaber (Williamson) = Bulimina scabra Williamson, 1858 Eratidus foleaceus (Brady) = Haplophragmium foleaceum Brady, 1881 Glomospira gordialis (Jones & Parker) = Trochammina squamata var. gordialis Jones & Parker, 186 Haplophragmoides bradyi (Robertson) = Trochammina bradyi Robertson, 1891 Jadammina macrescens (Brady) = Trochammina inflata Montagu var. macrescens Brady, 187 Leptohalysis gracilis (Kiaer) = Reophax gracilis Kiaer, 19 Leptohalysis scottii Chaster, 1892 Liebllsella goesi Hoglund, 1947 Portatrochammina murrayi Bronnimann & Zaninetti, 1984 Protoschista findens (Parker) = Lituola findens Parker, 187 Recurvoides trochamminiforme Hoglund, 1947 Reophax fusiformis (Williamson) = Proteonina fusiformis Williamson, 1858 Saccammina d. atlantica (Cushman) = Proteonina atlantica Cushman, 1944 Technitella legumen Norman, 1878 Textularia kattegatensis (Hoglund) = Textularia gracillima Hoglund, 1947 Textularia skagerakensis Hoglund, 1947 Textularia tenuissima Earland, 1933 Tritaxis britannica Bronnimann & Whittaker, 199. Tritaxis fusca (Williamson) = Rotalina fusca Williamson, 1858 Trochamminopsis quadriloba Hoglund, 1948 = Trochammina pusilla Hoglund, 1947 Usbekistania charoides (Jones & Parker) = Repmanina charoides (Jones & Parker) = Trochammina squamata Jones & Parker var. charoides Jones & Parker, ,

16 I.W. Mu rny" E. Aln P1a ' 1. Unl.bcl!cd ",,Ie l>al""i are 1 m. Sample numbo-no.", giv..., In pa'...,th... I, 2. IoJtrro"ym ".. ighli Brn;mann &. WhlHaker (2573 and 269 ""rectl, ely). 3, T.I,",,;, fusf:a (Williamson) (2573). 5 Rtpu fw5lfr"''' (Willi.ml<ln) (1432). ro 8 C"b.o.'"",id'l j'f!"y';; (W,Ili.mson) (285). 8 Delail of,he.p.-rtul"f' situated abo\ 1M ba", of the.periu ' faa.. 9, 1. C'ib 'o.. o'j... p. A (In",). 11-1l C"br...,onNliJI"S"p. A (265). 12 [too,ai] of the.p"rtu,... situated abo, e the b.lse of,he ap.-ttur.' lac"!! U, 14 CII"""..., (Brady) (]432). IS- I? [gg<'trll.,w,..,... Chri$tiansen (2573) 18 Lit-bu.. I'" g<jn' H6glun.d (l]).

17 Do shelf assemblages luye..,.'hwhile infom,.'i,,". fter dl.""lu,ion? M.'e 2- UnL>bel Kale ba.. 1 m. 5.>mp'" numbers are gi.. u, I'"""" 1 3 P"r,.,.",h.",,,,m. "'.".1" Bronnimann " l.>m",,' ti (l4j.4). 4, 5. T",;r,.,,'nnU". Bronnimann " Whittaker (IHf ) 6. Tatul.". 1m.,,,,;,,,. f;lflond (1441). 7, B /1.pJphf.g"'O,Jts.p. 1 (27)., 1 HOI,Joph'QgmoMrf br.dy; (Robertson) (1441) R«"""dt'$ I.",h.",,,,i.i!v.m, HOglund (257J). 14, 15. [u"rll<lid-s ",.w, (Willia",son) (2OS.'i and re'spi.'<clivciy). 16, 17, f.g:(,'r(limdt'$ mtdlu, (Hilgtund) (U41 and 285 fesp«tiv, ly) TatuJ.". sp 1 (ls?3). 2\ 23. o..u'r ",,,,'." (Dru". ",,,,i ) ' I. 'if"'''''' II leron-aii " Orland) (1434). 24, 25. H.plarh gmmde< sp 2 ( )