ROYAUME DE BELGIQUE MINISTERE DES AFFAIRES ECONOMIQUES Administration des Mines -Service geologique de Belgique 13, Rue Jenner. 1040 Bruxelles

QUANTITATIVE DISTRIBUTION AND PALEOECOLOGY OF BENTHONIC FORAMINIFERA RECORDED FROM SOME EOCENE DEPOSITS IN BELGIUM

By

M: GERITS, H. HOOYBERGHS and R. VOETS

PROFESSIONAL PAPER 1981/3

N° 182 BELGISCHE GEOLOGISCHE DIENST- PROFESSIONAL PAPER 1981/3 - N° 182

QUANTITATIVE DISTRIBUTION AND PALEOECOLOGY OF BENTHONIC FORAMINIFERA

RECORDED FROM SOME EOCENE DEPOSITS IN BELGIUM.

M. GERITS, H. HOOYBERGHS and R. VOETS

Laboratorium voor Mikropaleontologie Katholieke Universiteit Leuven Redingenstraat 16bis 3000 LEUVEN. - 2 -

CONTENTS

Part I : Quantitative distribution of benthonic foraminifera In the Ledc and Asse Formations (Eocene) at Zemst (Belgium). t. Sununary. 2. Introduction. Fig. t : Locality map. 3. Description of the studied sections. a) well n° 28 Fig. 2. Figs. 2a - 2b Grain-size analysis b) outcrop Fig. 3. 4. Lithostratigraphy. a) Lede Formation b) Asse Formation 5. Quantitative distribution of the benthonic foraminifera. Tables t and 2 6. Paleoecological interpretation. a) Introduction. b) Paleoecological conclusions.

Part II Quantitative distribution of benthonic foraminifera recorded from the Middle Eocene Brussels and Lede Formations at Haasrode and Nederokkerzeel (Belgium).

1 • Sununa ry. 2. Description of the sections and lithostratigraphy. a) Haasrode Fig. 4. b) Nederokkerzeel Fig. 5. 3. Quantitative distribution of the benthonic foraminifera. Tables 3 - 9 a) Haasrode b) Nederokkerzeel 4. Paleoecological conclusions.

Part III Quantitative distribution of the benthonic foraminifera re­ corded from the Lower Eocene leper Formations at Egem (Bel­ gium). t • Sununary. 2. Description of the Ampe clay and sandpit at Egem Fig. 6. 3. Lithostratigraphy. - 3 -

4. Quantitative distribution of the benthonic fora­ ·minifera in the Ampe clay and sandpit. Tables 10 and 11 5. Paleoecological conclusions.

Part IV Quantitative distribution of the benthonic foraminifera recorded from the Eocene Panisel Formation and Asse Formations at Zee­ brugge (Belgium).

I. Summary. 2. Introduction. Fig. 7 3. Lithostratigraphy. a) Panisel Formation. b) Asse Formation. 4. Quantitative distribution of the benthonic forami- fera. Tables 12 - 19 a) Panisel Formation ~) Asse Formation 5. Paleoecological conclusions. a) Panisel Formation b) Asse Formation

Acknowledgments Systematics. Superfamily Lituolacea Superfamily Miliolacea Superfamily Nodosariacea Superfamily Buliminacea Superfamily Discorbacea Superfamily Rotaliacea Superfamily Globigerinacea -- Superfamily Orbitoidacea Superfamily Cassidulinacea Bibliography - 4 -

Part I Quantitative distribution of benthonic foraminifera in the Lede and Asse Formations (Eocene) at Zemst (Belgium).

I. Summary.

Quantitative countings of benthonic foraminifera, recorded from the Lede and Asse Formations, have resulted in distribution charts of the most frequently occurring taxa. These distribution charts show five different foraminiferal assemblages within the Lede Sands and two different assemblages within the Asse Formation, corresponding to the Wemmel Sands respectively the Asse Clay. Using some general information from studies on Recent foraminiferal assem~ blages, a paleoecological interpretation of the different associations is worked out.

2. Introduction.

In prospecting the construction of a new sealock on the canal Brussels-Rupel, near to Kapelle-op-den-Bos, but still on the territory of Zemst (locality map in fig. 1), a few wells have been made to explore the subsoil of the region. The geological interpretation of the profile, constructed on the base of these wells, is published by GULINCK (1971) (Fig. 2). The Belgian Geological Survey delivered us samples from well n° 28 in order to study the benthonic foraminiferal assemblages in some striked Tertiary deposits. In 1969, the upper part of these deposits could be sampled in a temporary outcrop, caused by the digging works of the sealock. The study of the bent­ honic foraminifera in this outcrop allows us to control the local validity of some results, obtained from the well samples. The main aim of this study is to detail the vertical fluctuations in the dis­ tribution pattern of the benthonic foraminifera. Such fluctuations can be ex­ pected in the studied sections with distinctly changing sedimentological features. While observing some regular patterns within the vertical faunal distribution, we can try to work out a paleoecological interpretation, com­ paring our results with data from the literature on Recent assemblages.

3. Description of the studied sections. a) Well n° 28 (Fig. 2)

The Belgian Geological Survey delivered us samples from the interval in well 28 between -36,5 m and -17 m beneath the mowing field. In the interval -36,5 m and -36 m in the well, a very coarse heterogeneous quartz sand with nummulites has developed. - , -

Between -36 m and -35,5 m, the sand is still heterogeneous, but less coarse. It is followed up by rather fine calcareous sand between -35,5 m and -34,5 m. A calcareous sandstone has developed between -34,5 m and -34 m. The sediment is again distinctly coarser between 32,5 m and 32,3 m, and it is very rich in nummulites. In the rather heterogeneous calcareous and slightly glauconitic sand, developed between -32,3 m and -27,6 m, three sandy limestone beds, each 20 em thick, have developed. Between -27,6 m and -27,4 m, a fine calcareous sediment is slightly obdurated to a calcareous sandstone with nummulites. It is followed up by a coarser heterogeneous sand, rich in nummulites, developed between -27,4 m and-26m. In the interval -26 m to -20,5 m, a silty calcareous sand is observed. It is generally glauconitic, but it becomes richer in glauconite in the upper part. Between -20,5 m and -18,5 m a very sandy clay, extremely rich in coarse glau­ conite grains, has developed. MOlluscs and nummulites are observed between -20 m and -19,5 m. A sandy, slightly compact glauconitic clay occurs in the interval -18,5 m to -17m. The grainsize analysis of well n° 28 at Zemst is represented on figs. 2a and 2b. The suspention fraction smaller than 62w is drafted on the right side. On the left side, the remaining detrital sediment coarser than 62~ is brought to 100% and the half-phi fractions are joined. In this way, the variable im­ portance of the mixture of suspention fraction does not influence the charac­ teristics of the transported sand. Four sedimentological environments can clearly be distinguished.

-Layer A (samples 1 - 6). At the base, this layer is very coarse but rapidly it becomes a very fine sand with a mode around lOOp in samples 4, 5 and 6. Curve 5 shows the typical bimodality with a coarse bottom load, having a mode above 250~. The suspention fraction increases regularly. The environment is one of low energy but waves are still influencing the bottom.

-Layer B (samples 7- 20). This is characterized by an ill sorted sand, the sand-medium fluctuating around 170w. Curve 16 shows a mixture of three sand populations, proving a strong diversity of energy with suspention material mostly washed away. The energy is fluctuating : the mixture of a rapid succession of well sorted sands results in heterogeneous samples. It is a longshore undeep water en­ vironment.

-Layer C (samples 24- 35). This is a very homogeneous very fine sand, with an extraordinary fine mode around SOw • The fraction under 62w increases up to 25%. The sand is very well sorted and remains homogeneous over 6 m. The environment was one of low but rather constant energy. Between B and C, a layer of coarse sand with only 20% below 250w occurs (samples 22 and 23). The suspention fraction represents only 3%. It is a high energy level with strong currents and waves. It can not be the normal transi­ tion from B to C or from medium to low energy. It is considered as the high energy base of layer C, reworking the material of B. - 6 -

-Layer D (samples 36- 41).

The sand becomes much coarser againg. About 20% is coarser than 250~ and the mode is around 180~. The sand is fairly well sorted and unimodal (curves 36 - 39). Towards the top, the suspention fraction increases to a heavy cJay. The sand retains its same characteristics. The energy of transporting currents remains equal, but the sedimentation of suspention material increases. It can be explairted by a diminishing wave activity in a deeper sea.

b) Outcrop (Fig. 31).

In order to construct the sea-lock, a pit was dug along the canal Brussels - Rupel. In this temporary outcrop, about 3,75 m of Tertiary deposits could be observed beneath a Quaternary alluvium of 15 m thickness. The Tertiary deposits have been sampled every 0,25 m. The 15 samples are registered in the sample book of the Micropaleontological Laboratorium of the K.U.LEUVEN under the numbers B140 to Bl54. In the lowermost 1,25 m of the pit, a silty homogeneous calcareous and more or less glauconitic sand was visible. Small clay lenses have been observed in the sand between 1,25 m and 1,5 m above the base of the pit. The silty sand contains nummulites. Higher up, between 1,5 m and 2,25 m, a sandy and very glauconitic clay, rich in molluscs and nummulites can be found. Nummulites still occur in the lower part of the less glauconitic, more com­ pact clay between 2,25 m and 3,75 m above the base of the pit.

4. Lithostratigraphy.

a) Lede Formation

GULINCK (1971) recognized in well n° 28 the "Ledian" in the interval between -36,5 m and -27,6 m. A more detailed analysis however shows that the fine calcareous sand and calcareous sandstone from samples 20 and 21 can be in­ cluded in the Lede Formation. The coarse heterogeneous sand from sample 23 between -26,5 m and -26 m in the well, corresponds to the basal gravel of the Wemmel transgression. The basal gravel of the Lede Formation (KAASSCHIETER, 1961) contains coarse quartz grains and many reworked nummulites. Higher up, in samples 2 to 6 from well n° 28 at Zemst, a fine calcareous sand has developed. On top of this, a first sandy limestone bed occurs. This part of the section corresponds to the former "Laekenien s.s." of RUTOT (1878). A second pebble bed with nummu­ lites is observed in sample 7. It corresponds to the reoccurrent basal gravel of the Lede transgression. Above this reoccurrent basal gravel, the Lede Sands consist of ill sorted calcareous sands. Three thin sandy limestone beds occur in the middle part of the Lede Sands.' In the upper part of these Sands, a very fine heteromorf sandlayer has deve­ loped. The fine sediment is partly obdurated to a calcareous sandstone (samples 20 and 21). - 7 -

b) Asse Formation

The formal lithostratigraphic name "Asse Formation" is introduced by KAAS­ SCHIETER (1961). Three members are distinguished : the Wemmel Sands, the Asse Clay and the Asse Sands. In well n° 28 at .Zemst, the Wemmel Sands and the Asse Clay are developed.

- Wemmel Sands Member (-27,1 m -20,5 m) The coarse sediment from sample 22 corresponds to the basal gravel of the Wemmel transgression. Between -26 m and -20,5 m in well n° 28, the Wemmel Sands consist of silty homogeneous, calcareous and glauconitic sands with nummulites. In the temporary outcrop, the upper part of the Wemmel Sands could.be ob­ served (samples 1-6). It comprises a silty homogeneous calcareous and glau­ conific sand. Clay lenses are intercallated in the uppermost part of the Wemmel Sands.

- Asse Clay Member The coarse glauconitic clayey sand with molluscs (Pecten corneus) and nummu­ lites, developed between -20,5 m and -17 m in well n° 28, corresponds to the Asse Clay Member. In the temporary outcrop, this "Bande Noire" is about 1m thick (samples 7 to 9). Above this glauconite rich layer, the sandy Asse Clay becomes more compact. The Asse Clay Member is overlain by a Pleistocene deposit.

5. Quantitative distribution of the benthonic foraminifera. (Tables 1 and 2)

After treatnent with H2o2, the sediment was sieved. Countings of 200 speci­ mens per sample have been made in the sieve fractions larger than 125 micron. Altogether 97 species and subspecies were recognizee. In tables I and 2, the frequencies of the taxa reaching 5% of the foraminiferal assemblage in one or more samples are indicated. l.JeH n ° 28 at Zemst. -Levels I - 21 (Lede Formation). This interval is characterized by a number of species with distinct fluctua­ tions in the quantitative distribution. Five different characteristic assem­ blages can be distinguished. -Level 1. The foraminiferal population in this sample is characterized by the dominant occurrence of broken Miliolacea and of Quinqueloculina carinata. It is typi­ cal for this assemblage that no other taxa are of significant importance. - 8 -

- Levels 2 - 6. The frequencies of the broken Miliolacea and of Quinqueloculina carinata de­ crease distinctly in favour of some other taxa such as Triloculina angularis, Cibicides tenellus tenellus, Reusella limbata, Bifarina selseyensis, Rotalia propingua and a few frequently occurring taxa as Textularia agglutinans and Globulina gravida. gravida. Within this interval the frequency of Triloculina angularis decreases upwards, while those of Bifarina selseyensis and Rotalia propingua increase. Reussella limbata, Textularia agglutinans and Globulina gravida gravida occur more constantly. Remarkable is the fact that the fre­ quency of Cibicides tenellus tenellus changes in an opposite way to that of the broken Miliolacea.

- Levels 7 - 10. After the increase of the broken Miliolacea and of Quinqueloculina carinata in level 7, which is followed again by the increase of Triloculina angularis in the lower part of the interval, their frequencies in higher levels de­ crease. Remarkable is the fact that the limited occurrence of those taxa is compensated by other taxa than those in the samples 2 to 6. Instead of Cibi­ cides tenellus tenellus, Bifarina selseyensis and Rotalia propingua, especiaily Globulina gibba gibba and Asterigerina bartoniana occur, and partly or less distinctly Reussella limbata, Textularia agglutinans, Globulina gravida gravida and Guttulina irregularis.

-Levels 11- 19 In this interval the frequencies of broken Miliolacea and of Quinqueloculina carinata gradually increase. As in samples 2 - 6, the frequency of Cibicides tenellus tenellus, which becomes important again, changes in the opposite way to this of the Miliolacea. Another important fact is the distinct appea­ rance of Spiroloculina tricarinata belgica. A number of taxa as f.i. Reussella limbata, Bifarina selseyensis, Globulina gravida gravida, Globulina gibba gibba, Guttulina irregularis, Rotalia pro­ pingua and Asterigerina bartoniana occur fairly constantly, but less fre­ quently than before. -Levels 20- 21. In the fine heteromorf sand, developed at the top of the Lede Sands, a parti­ cular foraminiferal assemblage occurs. Some taxa, occurring in samples 11 to 19, still occur in nearly the same frequencies : Spiroloculina tricarinata belgica, Globulina gravida gravida and Asterigerina bartoniana. On the other hand, a renewal of the foraminiferal population is observed. Textularia agglutinans, Planulina burlingtonensis, Bolivina anglica and Nonion affine reappear.

- Levels 22 - 35 of well n° 28 and levels 1 - 6 of the outcrop. (Wemmel Sands Member). In this interval a homogeneous assemblage of benthonic foraminifera is ob­ served. It is characterized by the occurrence of Reussella limbata, Bifarina selseyensis, Textularia agglutinans, Planulina burlingtonensis, Bolivina an­ glica, Rotalia propingua, Asterigerina bartoniana, Cibicides tenellus crassus, Cibicides dutemplei and Nonion affine. However, the frequency of Asterigerina bartoniana strongly increases in sample 35. - 9 -

- Levels 36 - 40 of well n° 28 and levels 7 - IS of the outcrop (~~~~-.f.!2J_!f~.!!lE~E) • ------~------Asterigerina bartoniana and Cibicides dutemplei dominate the benthonic fora­ miniferal assemblage in the "Bande Noire". However, a renewal of the popu­ lation is observed : Bolivina cookei, Loxostomum teretum and Cibicides pygmeus appear in the assemblage. This renewal is distinctly consolidated higher up. The frequency of Bolivina cookei increases and Trifnrina wilcoxensis and Karreriella siphonella appear. Some other taxa as Globulina gibba punctata, Spiroplectammina carinata deper­ dita, Cibicides lobatulus and less distinctly Globulina gibba gibba and Guttulina irregularis occur more frequently.

6. Paleoecological interpretation.

a) Introduction.

From studies on Recent benthonic foraminifera, we know that based on generic associations different biofacies can be distinguished. These associations are controlled by environmental features. In studying fossil assemblages, problems arise concerning the validity of ecological criteria, known from studies on Recent assemblages. (WALTON, 1964) It could be possible that the adaptation to environmental circumstances changed through the geological time. It is considered however as unlikely that, during the Tertiary, generic distribution and mean population characters are significantly affected by changes in tolerance on specific levels. In trying to explain the paleoecological factors determining the fluctuations in the associations of benthonic foraminifera in the studied sections, we consequently mainly used the distribution of the most frequently occuring genera in the population. Rarely occurring taxa are less important to explain the paleoecological circumstances, controlling the composition of the popu­ lations. Some species may occur in distinctly different environments, but preferably and thus more frequently in some of them (f.i. at a distinct depth). The depth distribution of some genera can slightly change from one area to another. Other changing ecological factors as f.i. temperature, salinity, turbidity, foot supply and kind of substrate can interfere with the depth at which a species preferably occurs. Consequently, we can only try to indicate some trends in the depth distri­ bution of the populations.

b) Paleoecological conclusions.

The distinct dominance of broken Miliolacea and of Quinqueloculina carinata in level I of the Lede Sands, reflects a typical near-shore or littoral facies (BANDY, 1964). Quinqueloculina especially dominates as euryhaline genus in this littoral facies, in which the salinity distinctly changes un­ der the influence of run-off. In this turbulent environment, the thick walled miliolids are attached to coarse sand grains (PHLEGER, 1960). - 1() -

It is typicalfor this biofacies that other smaller benthonic foraminifera survive with difficulty. This level marks the basal transgression layer of the Lede Formation. The important enrichment of the foraminiferal assemblages in samples 2 - 6 reflects a changing environment. The more restricted occurrence of miliolids and the appearance of different other taxa indicate a deepening of the sea. In this slightly'deeper sea Triloculina (Triloculina angularis), which is also euryhaline appears, but its frequency decreases upwards with increasing depth of the sea. Cibicides (Cibicides tenellus tenellus) becomes the domi­ nant genus, but the faunal dominance is lower in this inner shelf zone than in the littoral environment observed below. The faunal variability however becomes larger in this inner shelf zone : Reussella, Bifarina and Rotalia occur. The new increase in miliolids in level 7 corresponds to the reoccur­ rence of the basal transgression layer. Again, Triloculina reaches its maximum frequency after the decrease of the miliolids. It disappears nearly completely with the new increasing depth of the sea. Asterigerina becomes the dominant genus in level 10, which indicates a more stable salinity in an inner to central shelf zone (BANDY, 1964). At this depth the faunal dominance is lower than before the reoccurrence of the basal transgression layer. In this environment the morphological simple agglutinated Textularia occurs more frequently (BANDY, 1964). The gradual increase of the miliolids in the interval 10- 19 reflects a regression of the sea. The distinct appearance on the euryhaline Spiroloculina also indicates a more distinctly changing salinity. In this inner shelf en­ vironment with ill sorted sediments, the frequencies of other genera as f.i. Asterigerina and .Textularia decrease. Cibicides, which dominates the foraminiferal population when the regression starts, is gradually superseded by the miliolids, with the decreasing depth of the sea. Remarkable is the renewal of the foraminiferal assemblages in the fine sediment, observed in samples 20 and 21. A mixture of the foramini­ feral associations from the upper part of the Lede Sands and from the Wemmel Sands is observed. The definitive transgression of the Wemmel sea is indi­ cated by the presence of a coarser sediment in level 22. The foraminiferal populations are remarkably constant in the interval 22 - 36. The diversity of the faunal association is distinctly higher than before. Agglutinated and calcareous perforated foraminifera coexist. Textularia and Asterigerina occur again more frequently. Those revivals are due to ~ morP silty sedimentation, with periodical turbidities, and to the more stable salinity in the inner to central shelf zone. In thiscentral shelf zone the coarsely perforate planispiral Planulina (BANDY, 1964) occurs as well. The presence of non-striated Bolivina (B. anglica) is another typical fea­ ture of the population at this depth (BANDY, 1964). Agglutinated foraminifera with more complex morphological features such as Spiroplectammina and Karreriella (with siphonate aperture) occur preferably at greater depth in the sea (BANDY, 1964). Their frequencies increase in the Asse Clay. In the central to outer shelf zone Bolivina species with striate surface (BANDY, 1964), Trifarina and Loxostomum occur. - 11 -

Part 2 Quantitative distribution of benthonic foraminifera recorded from the Middle Eocene Brussels and Lede Formations at Haasrode and Nederokkerzeel (Belgium).

1. Summary.

Benthonic foraminifera are recorded from two sandpits. The first is situated at Haasrode, where the Brussels sands are outcropping ; the second is situa­ ted at Nederokkerzeel (locality map in fig. 1.). In this second one, the Brussels Sands are overlain by the Lede Sands. The quantitative distribution charts of the benthonic foraminifera recorded from the Brussels Sands at Haasrode show a homogeneous association. At Nederokkerzeel, vertical fluctuations in the foraminiferal assemblages are observed. In the Lede Sands, a typical population of benthonic forami­ nifera occurs. A paleoecological interpretation of the different associations is worked out.

2. Description of the sections and lithostratigraphy. a) Haasrode.

In this sandpit, two profiles have been sampled : HI and H2, about 15 m apart (fig. 4). In both sections, a calcareous,slightly glauconitic yellow sand has developed. This fairly homogeneous sand shows a fine lamination. At different levels, sandstone beds are intercalated. Especially in profile H2, the sand is clayey in the lower part of the section. Thin clay lenses have developed here. On top of profile HI, a bed about 20 em thick and rich in molluscs, occurs. The sands outcropping in this sandpit correspond to the Brussels Formation. b) Nederokkerzeel.

In this sandpit, three different profiles have been sampled : NI, N2 and N3 (fig. 5). In the lowermost 4 m of N1 and at the base of the N2 and N3 sections, a homo­ geneous, calcarous yellow sand has developed. This sand is rich Ln molluscs. Thin sandstone beds occur in the NI profile. Higher up in the Nt profile, a gully-like structure has developed. This structure is filled up with a white sand which is especially rich in molluscs in the upper part. This sand is about 2 m thick in the studied profile. This part of the studied sections corresponds to the Brussels Formation. - 12 -

Above the Brussels Sands, a coarse sandstone layer about 25 em thick and rich in reworked nummulites and fish-teeth, has developed. It corresponds to the basal layer of the Lede transgression. Higher up, the Lede Sands are white in color and they contain scarse shell fragments.

3. Quantitative distribution of the benthonic foraminifera.

Countings of 200 specimens per sample have been made in sieve fractions = larger than 74 micron. The frequencies of taxa, representing at least 2% of the foraminiferal population in one or more samples, are indicated in tables 3-9. a) Haasrode.

The Quantitative distribution charts of benthonic foraminifera recorded from the Brussels Sands at Haasrode, show a homogeneous assemblage in the studied profiles. The population is dominated by Cibicides, especially C. westi, C. tallahatensis and C. tenellus tenellus. Less frequently, but also con­ stantly Elphidium laeve and Hanzawaia boueana occur. b) Nederokkerzeel.

- Brussels Sands The foraminiferal populations in the Brussels Sands at Nederokkerzeel show distinct fluctuations. Within the Brussels Sands, the assenililages are dominated by Cibicides. However Elphidium laeve and Hanzawaia boueana also occur constantly but less frequently. Within the genus Cibicides C. tenellus tenellus dominates in . samples N1 1-14. Higher up its frequency decreases and C. tallahatensis in­ creasingly dominates the population. C. tenellus tenellus however occurs again more frequently in the upper part of the Brussels Sands in profile N1 (samples N1 19-21). - Lede Sands A distinct enrichment of the foraminiferal assemQlage is observed in the Lede Sands. Besides the appearance of f.i. Asterigerina, Bifarina selseyen­ sis, Bolivina anglica, Reussella limbata, Reussella terquemi, Rotalia audouini and Textularia agglutinans, the revival of Miliolacea is especially important. Cibicides carinatus occurs more frequently, while other Cibicides species become less important in the foraminiferal assemblage. - 13 -

4.Paleoecological conclusions.

The benthonic foraminiferal assemblages recorded from the Brussels Sands are characterized by a remarkably dominant occurrence of Cibicides. At Haasrode, C. westi is the dominating species. In the lower part of the N1 profile at Nederokkerzeel, C. tenellus tenellus dominates,while higher up, C. tallahatensis becomes more important. According to BANDY (1960), the dominant occurrence of Cibicides is characteristic of a central shelf zone, where hyaline calcareous foraminifera most frequently occur at moderate temperature and salinity. In the central shelf zone, the occurrence of Cibicides is favoured by the large amount of sea-weed and shells of molluscs to which Cibicides is attached. The enrichment of the foraminiferal assemblages in the Lede Sands and espe­ cially the important occurrence of Miliolacea are explained by the littoral to inner shelf environment, marking the transgression on the Lede sea. - 14 -

Part 3 Quantitative distribution of the benthonic foraminifera recorded from the Lower Eocene Ieper Formation at Egem (Belgium).

I. Summary.

Quantitative countings have been made of the benthonic foraminifera recorded from the ~l~nders Clay and Mons-en-Pevele Sands, outcropping in the Ampe clay­ and sandpit at Egem. The vertical fluctuations in the quantitative distri­ bution of the benthonic foraminifera reflect a gradual regression of the sea.

2. Description of the Ampe clay and sandpit at Egem (figs. I and 6).

In the lowermost part of this quarry, a compact plastic micaceous gray clay is visible over about 2,5 m. Above this clay, a bed very rich in nummulites occurs (sample A7). It is succeeded by alternating beds of micaceous silts and clays (samples A8- A12). Shell fragments occur frequently above the first clay bed (sample AIO). Higher up, a fine grained micaceous and glauconitic silty sand with two beds rich in nummulites (samples A13 and AlS) has developed (samples AI3- AI8). Molluscs occur frequently higher up in this silty complex (sample Al7). On top of this complex a coarser sand layer with cross lamination and a bed very rich in molluscs occurs. In the uppermost part of the section, a sandstone layer has developed.

3. Lithostratigraphy.

The compact micaceous gray clay in the lower part of the quarry corresponds to the Flanders Clay. The alternating beds of silts and clays are considered to be the gradual transition from the Flanders Clay to the Mons-en-Pevele Sands. In the silty Mons-en-Pevele Sands different beds with molluscs and nummulites occur. These Mons-en-Pevele Sands are covered in the Ampe clay-and sandpit: by the Panisel Formation, the thickness of which is however very restricted here.

4. Quantitative distribution of the benthonic foraminifera 1n the Ampe clay and sandpit.

After treatement with H202, the sediment was sieved. Countings of 200 speci­ mens per sample were made in the sieve fractions larger than 74 micron. - 15 -

The foraminifera were concentrated by the CCL4 method in v1ew of the fact that these samples were extremely poor in foraminifera. The quantitative frequencies of the benthonic foraminifera are indicated 1n tables 10 and II. The distribution charts of the benthonic foraminifera, recorded from the Ampe quarry, show distinct fluctuations in the foraminiferal assemblages. Generally, three· different associations can be distinguished. a) Levels AI - A3.

The foraminiferal populations of the Flanders Clay are remarkably dominated by Cibicididae. In sample AI, they even constitute 74% of the whole assem­ blage, especially with C. tenellus tenellus (20%), C. proprius (18%), C. lobatulus (10%), and less frequently, C. carinatus and C. westi. Noniodjdae are also well represented, especially with N. scaphum (6%) and N. affine (5%). Higher up, the frequency of Cibicididae decreases (45% in sample A2, 42% ~n sample A3) in favour of Nonionidae (30% in sample 23% in sample A3). The frequency of Polymorphinidae, especially with Guttulina irregularis, Glo­ bulina gibba gibba and Globulina gravida gravida, increases gradually to 20% in level A3. b) Levels A7- All.

Cibicididae (about 45%) and Nonionidae (about 20%) still dominate the associa­ tion. Cibicides westi however is recorded only from sample AlO, while Cibici­ .des carinatus disappears completely. The frequency of Cibicides lobatulus increases to about 23% in sample AIO. Polymorphinidae, still important in sample A7, decrease distinctly higher up in this interval, while especially Bolivinidae, with B. anglica (19% in level A9), Buliminidae, with B. pari­ siensis (9% in sample A9) and Elphidiidea, with E. laeve (10% in sample All) become more important. c) Levels Al3- Al7.

The frequencies of Cibicididae increase distinctly (65% in sample Al5). C. lobatulus gradually becomes more important in the foraminiferal assemblage, while C. proprius occurs less frequently. The Nonionidae also occur less fre­ quently in favour of Elphidiidae in the lower part and Rotaliidae in the upper part of this interval.

5. Paleoecological conclusions.

According to PHLEGER (1960), the benthonic foraminiferal assemblage observed in samples AI - A3 occurs typically in a central shelf zone, with moderate - In -

temperature and constant salinity. The increase in Buliminidae and Elphidii­ dae, observed in samples A7- All can be explained by the shallowing of the water. The regression of the sea continues. This is indicated by the more frequent occurrence of Elphidiidae and Rotaliidae in the upper part of the Mons-en-Pevele Sands. - 17 -

Part 4 Quantitative distribution of the benthonic foraminifera recorded from the Eocene Panisel Fqrmation and Asse Formation at Zeebrugge (Belgium)

I. Summary.

This contribution deals with the quantitative distribution of benthonic foraminifera recorded from the Panisel Formation and the Asse Formation at Zeebrugge (locality map in fig. 1). Within the Panisel Formation, three different associations of benthonic foraminifera are recognized. The succee­ ding characteristic populations indicate a gradual regression of the sea. Within the Asse Formation they reflect a greater seadepht subsequently followed by a shallowing of the water.

2. Introduction.

In prospecting the construction of a new seaport at Zeebrugge, a few wells have been made to explore the subsoil (fig. 7). The Belgian Geological Survey provided us with samples from some of them in order to study the quantita­ tive distribution of the benthonic foraminifera in the striked Tertiary deposits. Samples have been studied from wells n° 235 (B5), n° 237 (B8), n° 239 (BIO) and n° 240 (BII).

3. Lithostratigraphy. a) Panisel Formation.

The Panisel Formation was studied in well n° 235 (B5) and n° 237 (B8). In the lower part, silty clays rich in shell fragments have develope~. The silty glauconitic sand higher up is less fossiliferous. The tickness of the observed sandstone beds varies (max. I min well n° 235). b) Asse Formation.

The Asse Formation is studied in wells n° 239 (BIO) and n° 240 (BII). Two members of this formation can be distinguished : the Wemmel Sands Member and the Asse Clay Member. At the base of the Wemmel Sands, a small gravel bed is developed. (BII). It contains black gravel pebbles and reworked nummulites. The Wemmel Sands consist of homogeneous calcareous glauconitic silty sands. - 18 -

In the wells at Zeebrugge, the transition between the Wemmel Sands Member and the Asse Clay Member is very distinct due to the presence of the "Bande Noire" at the base of the Asse Clay (B 10, B1 I). This "Bande Noire" is very rich in glauconite and contains a lot of nummulites and molluscs. The Asse Clay itself is a greenish gray, glauconitic and less fossiliferous clay.

4. Quantitative distribution of the benthonic foraminifera.

After treatment with H2o2, the sediment was sieved. Countings of 200 speci­ mens per sample were made in the sieve fractions larger than 74 micron. The foraminifera were concentrated by the CCL4 method in the samples of the Panisel Formation , this view. of the fact that these samples are extremely poor in foraminifera. The quantitative distributions of the benthonic foraminifera are given in tables 12 - 19.

a) Panisel Formation.

The quantitative distribution of the benthonic foraminifera in the Panisel Formation shows three distinctly different assemblages within this unit.

-Levels 19- 20 from well n° 235 (BS). This interval is characterized by a frequent occurrence of Polymorphinidae (32%), especially with Globulina gibba gibba and Guttulina irregularis. Nodosariidae (13%), especially with Lagena hexagona occur less frequently. Cibicididae (11% in level 19 and 36% in level 20), Anomalinidae (10%) especially with Hanzawaia producta and Discorbidae (11% in level 19) are also important.

-Levels 21 and 22 from well n° 235 (BS). The foraminiferal population is characterized by important revivals of Tex­ tulariidae (T. agglutinans) and Eponididae (E. schreibersi), each representing 20% of the assemblage. Polymorphinidae, Anomalinidae and Discorbidae are insignificant or even completely absent. Cibicides tenellus tenellus distinctly dominates within the Cibicides group. The occurrence of Nodosariidae remains constant.

-Level 23 from well n° 235 (BS). Remarkable in this assemblage is the distinct appearance of Miliolidae (20%), with Quinqueloculina seminula and Q. impressa. Elphidiidae (lR%), Rota­ liidae (Ammonia beccarri, 15%), Textulariidae (7%), Nodosariidae (9%), Eponidae (5%) and Cibicididae occur less frequently. C. tenellus tenellus disappears completely. - 19 -

b) Asse Formation.

-Levels 31 and 32 from well n° 239 (B10), and levels 38- 41 from well n° 240 (B11) (Wemmel Sands Member). In the Wemmel Sands Member, the foraminiferal population comprises especially Cibicididae, Bolivinidae, Uvigerinidae, Bagginidae, Discorbidae, Asterige­ rinidae, Eponididae and Nonionidae, without dominance of one or more of these groups. This population is consequently more diversified.

-Level 33 from well n° 239 (BIO) and levels 42- 43 from well n° 240 (Bl1) (Bande Noire). Typical of the benthonic foraminiferal assemblage in the "Bande Noire" at the base of the Asse Clay Member is the fairly high frequency of Textulariidae (15 to 20%) and the occurrence of f.i. Uvigerinidae, Bolivinidae and Baggi­ nidae.

- Levels 34 - 35 from well n° 239 (BlO) and levels 44 - 46 from well n ° 240 (B 11). The high frequencies of Bolivinidae and Uvigerinidae are especially impor­ tant in this assemblage. Trifarina muralis, occurring in the Wemmel Sands and in the "Bande Noire" disappears ·and is replaced by Trifarina wilcoxensis.

-Levels 36- 37 from well n° 239 (BIO) and level 47 from well n° 240 (Btl). A renewal of the foraminiferal population is observed. Ammonia beccarii, Elphidium minutum and Cibicides westi appear. The frequencies of other taxa as f.i. Bolivina anglica, Cancris subconicus and Trifarina wilcoxensis de­ crease distinctly.

5. Paleoecological conclusions. a) Panisel Formation.

According to BANDY (1960) and PHLEGER (1960), a benthonic foraminiferal population as observed in levels 19 and 20 from well n° 235 is characte­ ristic of a central shelf zone. The revival of E. schreibersi in levels 21 and 22 reflects a r~gression of the sea. BANDY (1960) noted that this species preferably occurs at a depth of -SO m. The important occurrence of Textulariidae could be explained by periodical turbidities in this environ­ ment, where silty sediments accumulated. The distinct revivals of Miliolidae, Elphidiidae and Rotaliidae reflect a continuing regression of the sea (PHLEGER, 1960). In this more littoral environment Textulariidae, Nodosarii­ dae, Eponididae and Cibicididae occur less frequently. - !(l -

b) Asse Formation.

The presence of, in particular Bolivinidae, Uvigerinidae and Bagginidae in the Wemmel Sands, can be explained by the fact that these sands are depo­ sited in a central shelf zone (PHLEGER, 1960). In the "Bande Noire" Spiroplectammina deperdita as morphological more com­ plex agglutinated species appears. This is due to the increasing depth of the sea. The increasing frequencies of Bolivinidae and Uvigerinidae in the Asse Clay are typical of a considerably deep sea. At this greater depth, Trifarina muralis is replaced by the competitive species T. wilcoxensis. The appearance of Ammonia beccarii and of Elphidium minutum however suggests a shallowing of the water. From this it may be concluded that the upper part of the Asse Clay Member in this locality has deposited in a less deep sea.

Acknowledgments.

The authors owe gratitude to the Belgian Geological Survey for providing them with samples from the boreholes at Zemst and Zeebrugge. They are greatly indebted to Prof. J. BOUCKAERT, Dr. DE MEUTER and Dr. LAGA for their stimulating interest and the careful readings of the manuscript. Special thanks are due to Prof. F. GULLENTOPS for his contribution to the grainsize analysis of the samples from well n° 28 at Zemst• and to Prof. F. GEUKENS in whose laboratories all studies have been carried out. - 21 - Systematics.

Superfamily Lituolacea DE BLAINVILLE, I825

Family Textulariidae EHRENBERG, I838 Subfamily Spiroplectammininae CUSHMAN, I927 Genus Spiroplectammina CUSHMAN, I927 Spiropl,ectammina carinata deperdita CUSHMAN, I927 + 1846 Textularia deperdita d'Orbigny- d'ORBIGNY, p. 244, pl. 14, figs. 23 - 25. v 196I Spiroplectammina carinata (d'ORBIGNY) var. deperdita d'ORBIGNY- KAASSCHIETER, p. 140, pl. I, fig. I9. 1974 Spiroplectammina deperdita (d'ORBIGNY) - MURRAY & WRIGHT, p. I21, pl. 1, figs. 4- 5.

Remarks As observed by KAASSCHIETER, the median ridge of our ·deperdita specimens varies from broad and granulated to narrow and smooth. Sp. carinata carinata (d'ORBIGNY, 1846), which differs from Sp. carinata deperdita by the dentate to spinose keeled periphery, has not been observed in our material.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation leper Formation : Flanders Clay Member

Subfamily Textulariinae EHRENBERG, 1838 Genus Textularia DEFRANCE, 1824 Textularia agglutinans d'ORBIGNY, 1839 + I839 Textularia agglutinans d'Orbigny- d'ORBIGNY, p. I44, pl. I, figs. 17, 18, 32, 33, 34 v 196I Textularia agglutinans d'Orbigny- d'ORBIGNY, p. 144, pl. I, figs. I4 - 16. 1974 Textularia agglutinans d'Orbigny- MURRAY & f,JRIGHT, p. I2l, pl. 1, figs. 7- 8.

Remarks Besides typical specimens with elongated test, nearly horizontal sutures and slightly inflated chambers, smaller individuals with more compressed test and divergent sides occur.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation. Panisel Formation.

Family Ataxophra.gmiidae SCHWAGER, 1877 Subfamily Globotextulariinae CUSH't-'f.AN, I927 Genus Karreriella CUSHMAN, 1933 Karreriella siphonella (REUSS, 185I) + I85I Gaudryina siphonella n. sp. -REUSS, p. 78, pl. 5, figs. 40 - 42. v I96I Karreriella siphonella (Reuss) - KAASSCHIETER, p. 143, figs. 21 - 23.

Remarks Both chilostoma type (with more inflated chambers and coarser agglutinated wall) and siphonella type occur in our material. - 22 -

Besides the conical microsferic form, the megalosferic form with rather parallel sides is also observed. In the megalospheric form, the initial triserial part of the test is more restricted than in the microspheric form.

Occurrence Asse Formation : Wemmel Sands Member and Asse Clay Member. - 23 -

Superfamily Miliolacea EHRENBERG, 1839

Miliolacea undet. spp.

Remarks : A lot of broken Miliolacea individuals occur. They could not be determined as species. Mostly, they represent specimens of Quin­ queloculina, but, though less frequently, also of Spiroloculina and Triloculina. In order to avoid a too subjective identification, these broken individuals are generally considered as "Miliolacea".

Occurrence : Asse Formation : Wemmel Sands Member Lede Formation Brussels Formation

Family Nubeculariidae JONES, 1875 Subfamily Spiroloculininae WIESLER, 1920 Genus Spiroloculina d'ORBIGNY, 1826 Spirolocul'ina canaliculata d'ORBIGNY, 1846 + 1846 Spiroloculina canaliculata d'Orbigny - d'ORBIGNY, p. 269, pl. 16, figs. 10 - 12 v 1961 Spiroloculina canaliculata d'Orbigny - KAASSCHIETER, p. 154, pl. 3, figs. 20 - 23.

Remarks Some of our specimens resemble S. obscura CUSHMAN & TODD, 1944, with less distinct sutures and with chambers which increase more rapidly in size.

Occurrence : Lede Formation

Spiroloculina tricarinata belgica KAASSCHIETER, 1961 v + 1961 Spiroloculina tricarinata Terquem var. belgica, nov. var. KAASSCHIETER, p. 153, pl. 3, figs. 12 - 14

Remarks : Our specimens mostly have a well rounded periphery.

Occurrence : Asse Formation : Wemmel Sands Member Lede Formation.

Spiroloculina tricarinata tricarinata TERQUEM, 1882 + 1882 Spiroloculina tricarinata Terq.(part) - TERQUEM, p. 158, pl. 16, figs. 19- 20. v 1961 Spiroloculina tricarinata Terquem - KAASSCHIETER, p. 153, pl. 3, fi figs. 9 - 11.

Remarks Most of our specimens have three well developed peripheral keels. Transitional forms to Sp. tricarinata belgica KAASSCHIETER, 1961 with a rounded periphery occur as well.

Occurrence : Asse Formation : Wemmel Sands Member Lede Formation. - 24 -

Family Miliolidae EHRENBERG, 1839 Subfamily Quinqueloculininae CUSHMAN, 1947 Genus Quinqueloculina d'ORBIGNY, I826 Quinqueloculina carinata d'ORBIGNY, 1850 + I850 Quiqueloculina carinata d'Orbigny - d'ORBIGNY, p. 4IO, fide ELLIS & MESSINA) v 1961 Quinqueloculina carinata d'ORBIGNY - KAASSCHIETER, p. 147, pl. 2, figs. 9 - 11. 1974 Quinqueloculina carinata d'ORBIGNY - MURRAY & WRIGHT, p. I20, pl. 2, figs. 13 - 15.

Remarks The cross section of the test of our specimens is more or less distinctly triangular, but we did not observe a clear transition to Q. lamarckiana d'ORBIGNY, 1839, which has very acute triangular cross-section. Specimens with a more angular periphery resemble Q. ludwigi REUSS, 1866.

Occurrence : Asse Formation : Wernrnel Sands Member Lede Formation Brussels Formation.

Quinoueloculina crassa d'O"RBIGNV, 1RSO + I850 0uinqueloculina crassa d'Orhigny - d'OR:RIGNV, p. 4()q v I96I Quinqueloculina crassa d'ORBIGNY - KAASSCHIETER, p. 151, pl. 3, figs. 3a - c. I970 Quinqueloculina crassa d'ORBIGNY - LE CALVEZ, p. 35, pl. 4, fig. I

Remarks Q. crassa differs from Q. grignonensis LE CALVEZ, I947 because of the more subcircular test.-

Occurrence : Lede Formation.

Quinqueloculina costata KARRER, I867 + 1867 Quinqueloculina costata Karrer - KARRER, p. 362, pl. 3, figs. 4a- c (fide ELLIS & MESSINA). v I96I Quinqueloculina costata KARRER- KAASSCHIETER, p. ISO, pl. 2, figs. I7a- I8c. I970 Quinqueloculina costata KARRER- LE CALVEZ, p. 34, pl. 3, figs. 7 - 8. I974 Quinqueloculina costata KARRER- MURRAY & WRIGHT, pl. 3, figs. 1 - 3.

Remarks In our specimens, the thickness and number of costae vary. Some specimens are difficult to distinguish from Q. juleana d 'ORBIGNY, I846

Occurrence : Lede Formation. - 25 -

Quinqueloculina impressa REUSS, 1851 + 1851 Quinqueloculina impressa Reuss- REUSS, p. 87, pl. 7, fig. 59 v 1961 Quinqueloculina impressa REUSS- KAASSCHIETER, p. 151, pl. 3, fig. 4a - 6c 1974 Quinqueloculina impressa Reuss - MURRAY & WRIGHT, pl. 3, figs. 7 - 9.

Remarks In our specimens, the sutures are less deeply depressed. A few specimens have a triloculine appearance since one side shows only two chambers.

Occurrence : Panisel Formation.

Quinqueloculina juleana d'ORBIGNY, 1846 + 1846 Quinqueloculina juleana d'Orbigny- d'ORBIGNY, p. 298, pl. 20, figs. I - 3. v 1961 Quinqueloculina juleana d'ORBIGNY- KAASSCHIETER, p. 149, pl. 2, figs. I4a - l5c. 1970 Quinqueloculina juleana d'ORBIGNY - LE CALVEZ, p. 36 1974 Quinqueloculina juleana d'Orbigny - MURRAY & WRIGHT, pl. 3, figs. 10 - I 2.

Remarks The elongated tests have a well developed neck and an angular periphery.

Occurrence : Lede Formation. Brussels Formation.

Quinqueloculina seminula (LINNE, 1758) + 1758 Serpula seminulum Linnaeus -LINNE, p. 736 (fide ELLIS & MESSINA) v 1961 Quinqueloculina seminula (LINNE) - KAASSCHIETER, p. 147, pl. 2, figs. Sa - 6c. 1970 Quinqueloculina seminulum (LINNE) - LE GALVEZ, p. 40, figs. 6 - 7. 1974 Quinqueloculina seminulum (Linne) -MURRAY & WRIGHT, pl. 2, figs. 19 - 21.

Remarks Some specimens are difficult to distinguish from Q. ludwigi REUSS, 1866, which has a wore elon~ated test and a well developed neck. Other individuals with a more angular periphery resemble Q. carinata (d'ORBIGNY, 1850). Specimens with more elongated tests resemble Q. vulgaris CUSHMAN, 1929.

Occurrence : Lede Formation. Brussels Formation Panisel Formation.

Quinqueloculina ludwigi REUSS, 1866 + 1866 Quinqueloculina ludwigi Reuss- Reuss, p. 126, pl. 1, figs. 12a - c. - ?.fi -

v 1961 Quinqueloculina ludwigi REUSS - KAASSCHIETER, p. 148, pl. 2, figs. 7a - 8c. 1970 Quinqueloculina ludwigi REUSS - LE GALVEZ, p. 37, pl. 4, figs. 2 - 3. 1974 Quinqueloculina ludwigi Reuss - MURRAY & WRIGHT, pl. 3, figs. 13 - IS.

Remarks Sometimes it is difficult to distinguish this species from Q.semi­ nulum (LINNE, 1758) which normally has a more prolonged test and an apertural neck. Transition forms are found in our materi:J1.

Occurrence : Lede Formation Brussels Formation.

Quinqueloculina striata d'ORBIGNY, 1843 1826 Quinqueloculina striata d'Orbigny - d'ORBIGNY, p. 301 (nom. nud.) + 1843 Quinqueloculina striata d'Orbigny- GUERIN- MENEVILLE, p. 10, pl. 3, figs. lOa- b (fide ELLIS & MESSINA) v 1961 Quinqueloculina striata d'ORBIGNY- KAASSCHIETER, p. 151, pl. 3, figs. Ia - 2c. 1970 Quinqueloculina striata d'ORBIGNY- LE GALVEZ, p. 41, pl. 3, fig. s.

Remarks As mentioned by KAASSCHIETER (1961) , this species differs from Q. costata KARRER, 1876 by its less elongated test with more and finer costae. Only a few specimens of our material could be distinctly classified under this species.

Occurrence : Lede Formation

Genus Triloculina d'ORBIGNY, 1826 Triloculina angularis d'ORBIGNY, 1850 + 1850 Triloculina angularis d'Orbigny - d'ORBIGNY, p. 409 v 1961 Triloculina angularis d'ORBIGNY - KAASSCHIETER, p. 166, pl. 5, fig. 15. 1970 Triloculina angularis d'ORBIGNY - LE GALVEZ, p. 49, pl. 13, fig. 9. 1974 Triloculina angularis d'Orbigny- MURRAY & WRIGHT, pl. 4, figs. 4 - 5.

Remarks Besides more typical specimens with slightly elongated tests, in­ dividuals, the width and length of which are equal in size occur. We did not observe specimens with a more subangular cross-section as hasT. trigonula (LAMARCK, 1804), instead of a triangular one, typical of T. angularis. Specimens with a more rounded periphery resemble T. gibba d'ORBIGNY, 1846.

Occurrence : Lede Formation. - 27 -

Triloculina gibba d'ORBIGNY, 1846 + 1846 Triloculina gibba d'Orbigny - d'ORBIGNY, p. 274, pl. 16, figs. 22 - 24. v 1961 Triloculina gibba d'ORBIGNY- KAASSCHIETER, p. 165, pl. 5, figs. 12a - 14c. 1970 Triloculina gibba d'ORBIGNY - LE CALVEZ, p. 49, pl. 8, figs. 3 - 4.

Remarks Specimens with more inflated chambers resemble T. trigonula (LAMARCK, 1804).

Occurrence : Lede Formation. - /8 -

Superfamily Nodosariacea EHRENBERG, 1838

Family Nodosariidae EHRENBERG, 1838 Subfamily Nodosariinae EHRENBERG, 1838 Genus Lagena WALKER & JACOB, 1798 Lagena h.exagona (WILLIAMSON, 1848) + 1848 Entosolenia squamosa (Montagu) var. hexagona Williamson - Williamson, p. 20, pl. 2, fig. 23 (fide ELLIS & MESSINA). 1974 Lagena hexagona (Williamson)- MURRAY & WRIGHT, p. 119.

Remarks The size of the hexagonal pattern of ribs varies in our specimens. A few specimens have a less distinct hexagonal pattern of ribs. They resemble L. squamosa (MONTAGU, 1803).

Occurrence : Brussels Formation Panisel Formation leper Formation : Mons-en-PeviHe Sands Member

Family Polymorphinidae d'ORBIGNY, 1839 Subfamily Polymorphininae d'ORBIGNY, 1839 Genus Globulina d'ORBIGNY, 1839 Globulina' gibba gibba d 1 ORBIGNY, 1826 + 1826 Globulina gibba Nob. - d'ORBIGNY, p. 266, Mod. n° 63. 1846 Globulina gibba d'Orbigny- d'ORBIGNY, p. 277 v 1961 Globulina gibba (d'ORBIGNY) - KAASSCHIETER, p. 183, pl. 7, figs. 6 - 7. 1970 Clobulina gibba d'ORBIGNY- LE GALVEZ, p. 84, pl. 17, figs. 3 - 4. 1974 Globulina gibba (d'Orbigny)- MURRAY & WRIGHT, p. 118.

Remarks The size of the central chamber varies in our material. This results in a variable outline of the test. Specimens with more compressed tests resemble G. inaequalis (REUSS, 1850).

Occurrence ; Asse Formation : Asse Clay Member, Wemmel Sands Member. Lede Formation Panisel Formation leper Formation Mons-en-Pevele Sands Members Flanders Clay Member.

Globulina gibba punctata d'ORBIGNY, 1~46 + 1846 Globulina punctata d'ORBIGNY- d'ORBIGNY, p. 229, pl. 13, figs. 17- 18. 1846 Globulina rugosa d'Orbigny- d'ORBIGNY, p. 229, pl. 13, figs. 19 - 20. 1846 Globulina tuberculata d'Orbigny- d'ORBIGNY, p. 230, pl. 13, figs. 21 - 22. v 1961 Globulina gibba (d'ORBIGNY) var. punctata d'ORBIGNY - KAASSCHIETER, p. 183, pl. 8, figs. 8 - 9. - 20 -

Remarks The kind of punctation varies. Specimens with punstations arranged in longitudinal rows represent the rugosa-type. Individuals with coarse punctations represent the tuberculata type of d'ORBIGNY.

Occurrence : Asse Formation Wemmel Sands Member, Asse Clay Member. Lede Formation.

Globulina gravida (TERQUEM, 1878). + 1878 Guttulina gravida Terq. - TERQUEM, p. 47, pl. 4, figs. 28- 32. v 1961 Globulina gravida (TERQUEM) - KAASSCHIETER, p. 184, pl. 8, fig. I I. 1970 Globulina gravida (Terquem) - LE CALVEZ, p. 87. 1974 Globulina gravida (Terquem)- MURRAY & WRIGHT, p. 119.

Remarks Specimens with a more rounded basal part of the test and deep su­ tures resemble G. ampulla (JONES, 1882) p. 267. Some specimens from the Wemmel Sands and from the Asse Clay show a very indistinct, fine striation. They are considered to be transi­ tional forms between this species and G. lineata (KAASSCHIETER, I 961) .

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member. Lede Formation. Panisel Formation leper Formation : Flanders Clay Member

Genus Guttulina d'ORBIGNY, 1839. Guttulina irregularis d'ORBIGNY, 1846. + 1846 Guttulina irregularis d'Orbigny- d'ORBIGNY, p. 226, pl. 13, figs. 9 - 10. v 1961 Guttulina irregularis (d'ORBIGNY) - KAASSCHIETER, p. 181, pl. 8, fig. 23. 1970 Guttulina irregularis (d'ORBIGNY) - LE CALVEZ, p. 92, pl. 20, fig. 3.

Remarks Some variation is observed in the lenght/width proportion of the test as well as in the size of the last chamber. Specimens with a slightly elongated test resemble G. bulloides REUSS, as figured by BATHIA, 1955, p. 676,_ pl. 67, fig. 28.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member. Lede Formation. Panisel Formation leper Formation Flanders Clay Member, Mons-en-Pevele Sands Member.

Guttulina lactea (WALKER & JACOB, 1798). + 1798 Serpula lactea Walker & Jacob -WALKER & JACOB, p. 634, pl. 14, fig. 4. v I 961 Guttulina lac tea nvALKER & JACOB) - KAASSCHIETER, p. I 82, pl. 8, fig. 5. 1970 Guttulina lactea (WALKER & JACOB) - LE CALVEZ, p. 93 - 30 -

Remarks Small specimens with a less distinct elongate test are rather difficult to distinguish from G. problema.

Occurrence : Lede Formation Brussels Formation Pani~el Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Guttulina problema d'ORBIGNY, 1846. 1826 Polymorphina (Guttulina) problema d'Orbigny- d'ORBIGNY, p. 266 (nom. nud.) + 1846 Guttulina problema d'Orbigny- d'ORBIGNY, p. 224, pl. 12, figs. 26 - 28. v 1961 Guttulina problema (d'Orbigny)- KAASSCHIETER, p. 181, pl. 7, figs. 30 - 32, pl. 8, fig. 1. 1970 Guttulina problema d'ORBIGNY- LE CALVEZ, p. 94, pl. 19, fig. 4. 1974 Guttulina problema d'Orbigny- MURRAY & WRIGHT, p. 129.

Remarks This species resembles G. austriaca, but it should have more typical elongated chambers and the bases of the secondary cham­ bers are less embracing.

Occurrence : Panisel Formation leper Formation Flanders clay Member, Mons-en-Pevele Sands Member.

Genus Pyrulina d'ORBIGNY, 1839 Pyrulina thouini (d'ORBIGNY, 1826) Polymorphina gutta d'Orbigny- d'ORBIGNY, p. 167, pl. 12, figs. 5 - 6. v 1961 Pyrulina thouini (d'ORBIGNY) - KAASSCHIETER, p. 185, p 1. 8, figs. 13, 14. 1970 Pyrulina thouini (d'ORBIGNY) - LE CALVEZ, p. 97, 1974 Pyrulina thouini (d'Orbigny) - MURRAY & WRIGHT, p. 120.

Remarks Specimens with a less elongate test resemble P. cylindroides (ROEMER, 1839).

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member

Family Glandulinidae REUSS, 1860 Subfamily Oolinae LOEBLICH & TAPPAN, 1961 Genus Fissurina REUSS, 1850 Fissurina marginata (WALKER & JACOB, 1784). + 1784 Serpula marginata Walker & Boys -WALKER & JACOB, p. 2, pl. 1, fig. 7 (fide ELLIS & MESSINA). v 1961 Entosolenia marginata (Walker & Boys) - KAASSCHIETER, p. 180, pl. 7, fig. 28. 1974 Fissurina marginata (Walker & Boys)- HURRAY & WRIGHT, p. 118, pl. 6, fig. 5. - 31 -

Remarks : The width of the peripheral keel varies.

Occurrence Asse Formation : Wemmel Sands Member, Asse Clay Member. Panisel Formation. - ]~ -

Superfamily Buliminacea

Family Bolivinitidae CUSH~ffiN, 1927 Genus Bolivina d'ORBIGNY, 1939 Bolivina anglica CUSH~, 1936 + 1936 Bolivina anglicaCushrnan- CUSHMAN, p. 50, pl. 7, fig. II. v I96I Bolivina anglica CUSH~ - KAASSCHIETER, p. 194, pl. 9, figs. 18-19. 1970 Bolivina anglica CUSHHAN- LE CALVEZ, p. Ill. Remarks : In our specimens, the height of the chambers in the later part of the test varies. Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member. Bolivina carinata TERQUEM, 1882. + 1882 Bolivina carinata TER. - TERQUEM, p. 148, pl. IS, figs. 19a-b. v 1961 Bolivina carinata TERQUEM -KAASSCHIETER, p. 193, pl. 9, figs. 12-I4. 1970 Bolivina carinata TERQUEM- LE CALVEZ, p. 111, pl. 22, fig. 3. Remarks : The lenght width proportion of the test varies. Occurrence : Asse Formation : Wemrnel Sands Member, Asse Clay Member Lede Formation Panisel Formation leper Formation : Flanders Clay Member Bolivina cookei CUSHMAN, 1922 + 1922 Bolivina cookei Cushman- CUSHMAN, p. 126, pl. 29, fig. 1. v 1961 Bolivina cookei CUSH~ - KAASSCHIETER, p. 195, pl. VIII, figs. 25-26. Remarks : The costae vary from thin and restricted in the earlier part of the test, to very distinct along the whole test. Occurrence : Asse Formation : Asse Clay Member.

Bolivina crenulata CUSH~, 1936 + 1936 Bolivina crenulata Cushman, n. sp. - CUSH~, p. 50' pl. 7, fig. 13. v 1961 Bolivina crenulata CUSH~ - KAASSCHIETER, p. 194, pl. 9, figs 15a-17b. 1970 Bolivina crenulata CUSH~ - LE CALVEZ, p. 119, pl. 22, fig. 8 1974 Bolivina crenulata Cushman -MURRAY & WRIGHT, pl. 6, fig. 12. Remarks : The sutures become indistinct at the crenulate basal part of the chambers. Occurrence : Lede Formation. - ~3 -

Family Buliminidae JONES, 1875 Subfamily Bulimininae JONES, 1875 Genus Bulimina d'ORBIGNY, 1826 Bulimina parisiensis KAASSCHIETER, 1961 v + 1961 Bulimina parisiensis nov. nom. - KAASSCHIETER, p. 190, pl. 8, figs. 19a-c, pl. 9, figs. 3a-4c. 1970 Bulimina parisiensis KAASSCHIETER- LE CALVEZ, p. 118, pl. 21, fig. 4. Remarks : Some specimens with a smaller last chamber resemble B. candita (TERQUEM, 1882). Occurrence : Asse Formation : Wermnel Sands Member, Asse Clay Hember Panisel Formation leper Formation. Subfamily Pavonininae EIMER & FICKERT, 1899 Genus Reussella GALLOWAY, 1933 Reussella limbata (TERQUEM, 1882). f 1882 Reussella limbata Terq.- TERQl~M, p. 105, pl. 11, fig. 12 v 1961 Reussella limbata Terquem - KAASSCHIETER, p. 192, pl. 8, figs. 20-21. Remarks Some of our specimens have a less angular peripheral border. Other individuals show a peripheral keel which is interrupted by spines at the lower part of the test. Occurrence : Asse Formation : Wemmel Sands Member, Lede Formation. Reussella terquemi CUSHMAN, 1945 + 1945 Rcussella terquemi Cushman, n. sp. - CUSHMAN, p. 28, pl. 5, figs. 15-16. v 1961 Reussella terquemi CUSHMAN - KAASSCHIETER, p. 192, pl. 9, fig. 11. 1970 Reussella terquemi CUSHMAN- LE CALVEZ, p. 121, pl. 24, fig. 7. 1974 Reussella terquemi Cushman- MURRAY & WRIGHT, p. 121. Remarks : Only a few specimens have distinctly developed spines at the base of the chambers. Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation leper Formation : Flanders Clay Member

Family Uvigerinidae HAECKEL, 1894 Genus Uvigerina d'ORBIGNY, 1826 Uvigerina farinosa HANTKEN, 1875. + 1875 Uvigerina farinosa Hantken- HANTKEN, p. 62, pl. 7, fig. 6 (fide ELLIS & t-1ESSINfi). v 1961 Uvigerina farinosa HANTKEN - KAASSCHIETER, p. 196, pl. 9, fig. 21. Remarks : All our spec1mens have a triserial test. Occurrence : Asse Formation : Wermnel Sands Member, Asse Clay Member. - ·~4 -

Genus Trifarina CUSH~~. 1923 Trifarina abbreviata abbreviata (TERQUEM, 1882) + 1882 Uvigerina abbreviata Terquem- TERQUEM, p. 120, pl. 12, fig. 33. 1970 Uvigerinella abbreviata (TERQUEM) - LE CALVEZ, p. 124, pl. 26, fig. 4. 1974 Uvigerinella abbreviata (Terquem) - MURRAY & WRIGHT, p. 122, pl. 7, fig. 6.

Remarks According to the systematics of LOEBLICH & TA~AN, this taxon belongs to Trjfarina.

Occurrence : leper Formation.

Trifarina muralis (TERQUEM, 1882) + 1882 Uvigerina muralis Terq. - TERQUEM, p. 119, pl. 12, figs. 26- 29 v 1961 Angulogerina muralis (TERQUEM) - KAASSCHIETER, p. 199, pl. 10, figs. 3a - 4c. 1970 Angulogerina muralis (TERQUEM) - LE CALVEZ, p. 124, pl. 23, fig. 1. 1974 Uvigerina muralis Terquem- MURRAY & WRIGHT, pl. 7, fig. 3.

Remarks The peripheral angles are slightly rounded. Specimens with more inflated chambers have a less distinct trigonal cross section.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation. leper Formation : Flanders Clay Member

Trifarina wilcoxensis (CUSHMAN & PONTON, 1932). + 1932 Pseudouvigerina wilcoxensis Cushman & Ponton, n. sp. - CUSHMAN & PONTON, p. 66, pl. 8, fig. 18. v 1961 Trifarina wilcoxensis (CUSHMAN & PONTON) - KAASSCHIETER, p. 199, pl. 10, figs. 6- 7. 1970 Trifarina wilcoxensis (CUSHMAN & PONTON) - LE CALVEZ, p. 127, pl. 23, fig. 5 1974 Trifarina wilcoxensis (Cushman & Ponton) -MURRAY & WRIGHT, p. 122, pl. 7, fig. 5.

Remarks Adult specimens become uniserial. The canaliculate periphery 1.s vJell developed. The sutures are distinctly curved and the wall is coarsely perforated.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member, Brussels Formation. Panisel Formation. - 35 -

Superfamily Dis.corbacea EHRENBERG, 1838 Family Discorbidae EHRENBERG, 1838 Subfamily Baggininae CUSHMAN, 1927 Genus Cancris DE MONTFORT, 1808 Cancris subconicus (TERQUEM, 1882). + 1882 Rotalina subconicus Terq. - TERQUEM, p. 61, pl. 41, figs. 4 - 5 v 1961 Cancris subconicus (TERQUEM) - KAASSCHIETER, p. 213, pl. 12, 1970 Cancris subconicus (TERQUEM) - LE CALVEZ, p. 145, pl. 43, fig. 6. 1974 Cancris subconicus (Terquem) -MURRAY & WRIGHT, p. I 17, pl. 9, figs. 12 - 14.

Remarks Specimens with a less rounded periphery resemble C. auriculus (FICHTEL & MOLL, 1803).

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Panisel Formation leper Formation : Flanders Clay Member

Family Asterigerinidae d'ORBIGNY, 1839 Genus Asterigerina s'ORBIGNY, 1839 Asterigerina bartoniana (TEN DAM, 1944) + 1944 Rotalia granulosa nov. spec. - TEN DAM, p. 121, pl. 4, fig. 2. v 1961 Asterigerina bartoniana (TEN DAM) - KAASSCHIETER, p. 232, pl. 16, figs. 2 - 3.

Remarks Our specimens show a variability in their morphological features as described by KAASSCHIETER (1961).

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member. Lede Formation.

Asterigerina sp. cf. A. guerrai (BERMUDEZ, 1952). + 1952 Asterigerina guerra1 Bermudez- BERMUDEZ, p. 204, pl. I, fig. 4. v 1961 Asterigerina sp. cf. A. guerrai (BERMUDEZ) - KAASSCHIETER, p. 233, pl. 16, fig. 1. 1970 Asterigerina guerrai BERMUDEZ- LE CALVEZ, p. 152, pl. 31, fig. 2. 1974 Asterigerina cf. A. guerrai (Bermudez) - MURRAY & WRIGHT, p. 116.

Remarks The secondary chamberlets are less distinct and the arched aper­ ture extends more to the periphery than that of the typical spe­ c1mens.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Panisel Formation leper Formation : Flanders Clay l~e·mber

Asterigerina spp.

Remarks : Our specimens from the Brussels and Lede Formations differ from those decribed by KAASSCHIETER (1961) in the less convex dorsal side. They also have a higher subcircular aperture. - 31l -

Other specimens from the Panisel and AsseFormations resemble A. spp. cf. A. glabra (BERMUDEZ, 1952).

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation Brussels Formation Panisel Formation

Asterigerina tatumi HUSSEY, 1951 + Asterigerina tatumi Hussey, n. sp. -HUSSEY, p. 19, pl. 3, figs. I - 3.

Remarks Our specimens differ from those described by HUSSEY in the con­ vexity of the test. As HUSSEY's specimens have a distinct bi­ convex test, those found in our material show a planiconvex to very slightly biconvex one. The ventral side is distinctly more convex than the dorsal.

Occurrence : Lede Formation Brussels Formation. - 37 -

Occurrence : Panisel Formation

Elphidium spp.

In the Panisel Formation specimens resembling Elphidium ungeri (REUSS, 1850) occur but they have a more angular periphery and shorter "retral processes".

Occurrence : Panisel Formation

? Elphidium ungeri (REUSS, 1850) ?+ 1850 Polystomella ungeri Reuss - REUSS, p. 369, pl. 48, fig. 2. ? 1939 Elphidium ungeri (Reuss) CUSHMAN, p. 44, pl. 11, fig. 20. ? 1958 Elphidium ungeri (REUSS) - BATJES, p. 165, pl. 12, fig. 3.

Remarks Our specimens have a more angular periphery and less developed retral processes.

Family Rotaliidae EHRENBERG, 1839 Subfamily Rotaliinae EHRENBERG, 1839 Genus Ammonia BRUNNICH, 1772 · Ammonia beccarii CLINNAEUS, 1758) + 1758 Nautilus beccarii Linnaeus- LINNAEUS, p. 710, pl. 1, figs. I a - c (fide ELLIS & ~1ESSINA). 1928 Rotalia beccarii (Linne) -CUSHMAN, p. 103, pl. 15, figs. - 7. 1958 Rotalia beccarii (LINNE)- BATJES, p. 167, pl. 12, fig. 11.

Remarks Our specimens resemble A. beccarii, but CUSHMAN (1928) noted that different subspecies might be considered in the fossil material.

Occurrence : Asse Formation : Asse Clay Member Panisel Formation

Genus Rotalia LAMRCK, 1804 Rotal ia audouin i d 'OPRIGNY, 1850 + 1850 Rotalia

Remarks All transitional forms occur between typical R. audouini specimens and R. armata d'ORBIGNY, 1850.

Occurrence : Lede Formation leper Formation. - 18 -

Superfamily Rotaliacea EHRENBERG, 1839

Family Elphidiidae GALLOWAY, 1933 Subfamily Elphidiinae GALLOWAY; I 933 Genus Elphidium DE MONTFORT, 1808 Elphidium inflatum (REUSS, 1861) ?+ 1861 Polystomella inflata Reuss -REUSS, p. 358, pl. I, fig. 10. ? 1939 Elphidium inflatum (Reuss) - CUSHMAN, p. 46, pl. 12, fig. 7. ? 1958 Elphidium inflatum (REUSS) - BATJES, p. 164, pl. 12, fig. 2.

Remarks There is a good resemblance between our specimens and those figured by CUSHMAN, which however are recorded from the Miocene.

Occurrence : Panisel Formation.

Elphidium laeve (d'ORBIGNY, 1826) + 1820 Nonionina laevis d'Orbigny - d'ORBIGNY, p. 294 (fide ELLIS & MESSINA). v 1961 Elphidium laeve (d'ORBIGNY) - KAASSCHIETER, p. 239, pl. 16, figs. 15 - 16. 1970 Elphidium laeve (d'ORBIGNY) - LE CALVEZ, p. 168, pl. 25, fig. 1. 1974 Elphidium laeve (d'Orbigny) MURRAY & WRIGHT, p. 120, pl. 13, figs. 9 - I 3.

Remarks Specimens with a less deeply incised area around the umbilicus are difficult to distinguish from E. subnodosum (MUNSTER, 1838).

Occurrence : Lede Formation Brussels Formation Panisel Formation leper Formation : Flanders Clay Member, Mbns-en-Pevele Sands Member.

Elphidium minutum (REUSS, 1863) + 1863 Polystomella minutum Reuss - REUSS, p. 478, pl. 4, fig. 6. 1970 Elphidium minutum (REUSS) - LE CALVEZ, p. 169, pl. 27, fig. 1974 Elphidium minutum(Reuss)- MURRAY & WRIGHT, p. 118

Occurrence Asse Formation : Asse Clay Member Panisel Formation : Aalter Sands Member.

Elpidium subnodosum (ROEMER, 1838) + 1838 Robulina subnodosa von Munster- ROEMER, p. 391, pl. 3, figs. 6a - b. v 1961 Elphidium subnodosum (ROEMER) - KAASSCHIETER, p. 239, pl. 16, figs. 17 - 18. 1970 Elphidium subnodosum (MUNSTER) - LE CALVEZ, p. 170, pl. 25, fig. 7.

Remarks Most of our individuals are rather small. - 39 -

Rotalia propingua REUSS, 1856 + 1856 Rotalia propingua Reuss -REUSS, p. 241, pl. 4, fig. 53, (fide ELLIS & MESSINA) v 1961 Rotalia propingua REUSS - KAASSCHIETER, p. 243, pl. 16, fig. 12.

Remarks Our specimens show the same ~ariability in the presence of an um­ bilical knob and in the more deeply incesed sutures around the umbilicus as described by KAASSCHIETER (1961).

Occurrence : Asse Formation : Asse Clay Member, Wemmel Sands Member. Lede Formation. - 40 -

Superfamily Globigerinacea CARPENTER, PARKER & JONES, 1862

Family Heterohelicidae CUSHMAN, 1927 Subfamily Heterohelicinae CUSHMAN, 1927 Genus Bifarina PARKER & JONES, 1872 Bifarina selseyensis (HERON - ALLEN & EARLAND, 1909) + 1909 Bigeneria selseyensis Heron - Allen & Earland - HERON -ALLEN & EARLAND, p. 330, pl. 15, figs. 15 - 17. v 1961 Bifarina selseyensis (HERON - ALLEN & EARLAND) - KAASSCHIETER, p. 200, pl. 10, figs. 8a - lOb.

Remarks Specimens with an uniserial final part of the test are not observed in our material.

Occurrence : Wemmel Formation Lede Formation. - 41 -

Superfamily Orbitoidacea SCHWAGER, 1876

Family Eponididae HOFKER, 1951 Genus Eponides DE MONTFORT, 1888 Eponides schreibersi (d'ORBIGNY, 1846) + 1846 Rotalia schreibersi d'Orbigny - d'ORBIGNY, p. 154, pl. 8, figs. 4 - 6. v 1961 Eponides schreibersi d'ORBIGNY- KAASSCHIETER, p. 210, pl. 11, figs. 14 - 15. 1963 Eponides schreibersi d'ORBIGNY - KUMMERLE, p. 49, pl. 8, figs. Ia - c.

Remarks The convexity of the ventral side varies slightly. The aperture extends more or less to the periphery.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation Panisel Formation

Eponides spp.

In the Asse Formation, several small Eponides individuals occur. Their identification was impossible due to the small size of their tests.

Occurrence : Asse Formation : Asse Clay Member, Wemmel Sands Member

Family Cibicididae CUSHMAN, 1927 Subfamily Planulininae BERMUDEZ, 1952 Genus Planulina d'ORBIGNY, 1826 Planulina burlingtonensis (JENNINGS, 1936) + 1936 Cibicides burlingtonensis nov. sp. - JENNINGS, p. 39, pl. 5, fig. 5. v 1961 Planulina burlingtonensis (JENNINGS) - KAASSCHIETER, p. 224 pl. 14, figs. 9 - 10.

Remarks The ventral side is partly involute and the sutures are recurved. In some specimens, the aperture extends from the periphery to the umbilicus.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation Brussels Formation Panisel Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Subfamily Cibicidinae CUSHMAN, 1927 Genus Cibicides DE MONTFORT, 1808 Cibicides carinatus (TERQUEM, 1882) + 1882 Truncatulina carinata Terquem - TERQUEM, p. 94, pl. 10, figs. 1 - 2. v 1961 Cibicides carinatus (TERQUEM) - KAASSCHIETER, p. 221' pl. 14' fig. 6. 1970 Cibicides carinatus (TERQUEM) - LE CALVEZ, p. 180, text- figs. 66 - 68. 1974 Cibicides carinatus (Terquem) -MURRAY & WRIGHT, p. I 17, 'pl. 15' figs 4 - 6. Remarks : Our species have a well developed peripheral keel.

Occurrence : Lede Formation Brussels Formation leper Formation : Flanders Clay Member

Cibicides dutemplei (d'ORBIGNY, 1846) + 1846 Rota1ia dutemplei d'Orbigny- d'ORBIGNY, p. 157, pl. 8, figs. 19 - 2 l . v 1961 Cibicides dutemplei (d'ORBIGNY) - KAASSCHIETER, p. 218, pl. 12, fig. 15.

Remarks Our specimens are planoconvex to slightly biconvex. There are 8 to 10 chambers in the last whorl. The wall is coarsely perforated. Sometimes however, it becomes difficult to distinguish this species from C. tenellus tenellus (REUSS, 1865), C. lobatulus (WALKER & JACOB, 1798) or C. propius acutimargo TEN.DAM, 1944.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Mewber Lede Formation

Cibicides lobatulus (WALKER & JACOB, 1798) + 1798 Nautilus lobatulus Walker & Jacob -WALKER & JACOB, p. 642, pl. 14, fig. 36 (fide ELLIS & MESSINA) v 1961 Cibicides lobatulus (WALKER & JACOB) - KAASSCHIETER, p. 221, pl. 114, fig. 5. 1970 Cibicides lobatulus (WALKER & JACOB) - LE CALVEZ, p. 181 1974 Cibicides lobatulus (Walker & Jacob) - MURRAY & WRIGHT, pl. 15, figs. 13- 19.

Remarks Our specimens have a lobate periphery and a flat dorsal side. The wall is coarsely perforated. Specimens from the Wemmel Sands and Asse Clay have a more pronounced convex umbilical side. Sometimes, it is difficult to distinguish our specimens from C. tenellus tenellus (REUSS, 1865) or C. carinatus (REUSS, 1882).

Occurrence : Asse Formation : Asse Clay Member, Wemmel Sands Member, Lede Formation Brussels Formation Panisel Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member. Cibicides mauricensis HOWE & ROBERTS, 1939 + 1939 Cibicides mauricensis HOWE & ROBERTS -HOWE & ROBERTS, p. 87, pl. 13, figs. 4- 5 (fide ELLIS & MESSINE). v 1961 Cibicides sp. cf. C. mauricensis HOWE & ROBERTS - KAASSCHIETER, p. 223, pl. 14, fig. 8. 1970 Cibicides mauricensis HOWE & ROBERTS - LE CALVEZ, p. 182, pl. 40, figs. 4 - 6. 1974 Cibicides mauricensis Howe & Roberts -HURRAY & WRIGHT, p. 11 7, p 1. 16, figs. 1 - 2 •

Remarks The convexity of the ventral side varies and the periphery is sub­ angular to rounded. Some specimens lack the umbilical knob.

Occurrence : Lede Formation Brussels Formation

Cibicides proprius proprius (BROTZEN, 1948) + 1948 Cibicidoides proprius Brotzen - BROTZEN, p. 78, v 1961 Cibicides proprius (BROTZEN) - KAASSCHIETER, p. 202, pl. 13, figs. 9a - c. 1970 Cibicidoides prbprius BROTZEN- LE CALVEZ, p. 200, pl. 41, figs. 1 - 2. 1974 Cibicidoides proprius Brotzen - MURRAY & WRIGHT, pl. 20, figs. 3, 5, 6.

Remarks Sometimes, it becomes difficult to distinguish this species from C. proprius var. acutimargo (TEN DAH, 1944) which has a more rounded periphery and finer pores on the dorsal side.

Occurrence : Lede Formation Brussels Formation

Cibicides proprius acutimargo (TEN DAM, 1944) + 1944 Cibicides cryptomphala (REUSS) var. acutimargo nov. var. TEN DAM, p. 133, pl. 5, fig. 4. v 1961 Cibicides proprius (REUSS) var. acutimargo TEN DAM- KAAS­ SCHIETER, p. 122, pl. 14, fig. 7.

Remarks The test of adult specimens becomes lobate. Most of our specimens are biconvex. Specimens with slightly curved sutures are difficult to distinguish from C. proprius (BROTZEN, 1948).

Occurrence : Ass.e Formation : Weimllel Sands Member, Asse Clay Member Brussels Formation Panisel Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Cibicides pygmeus (HANTKEN, 1875) + 1875 Pulvilina pygmea nov. spec. - HANTKEN, p. 78, pl. 10, fig. 8 (fide ELLIS & MESSINA). - 44 -

v 1961 Cibicides pygrneus (HANTKEN) - KAASSCHIETER, p. 219, pl. 14, figs. Ia - c. 1974 Cibicides pygmeus (Hantken) - MURRAY & WRIGHT, pl. I 6, figs. 6 - 8.

Remarks This species is recognized by its rather trochospiral and rounded test. KAASSCHIETER (1961) observed juvenile specimens with an Eponides aperture (interiomarginal arc without internal tooth-plate). Our specimens show an interiomarginal opening with narrow lip.

Occurrence : Asse Formation : Asse Clay Member. Lede Formation.

Cibicides tenellus crassus GROSSHEIDE & TRUNKO, 1965 + 1965 Cibicides tenellus crassus n. subsp. - GROSSHEIDE & TRUNKO p. 1S 1' p 1. 14' fig. 7.

Remarks The umbilical side of the planoconvex test shows 9 to 10 chambers. The wall is more coarsely perforated than that of C. tenellus tenellus (REUSS, !8oS). However small specimens are difficult to distinguish from C. tenellus tenellus. As we could observe in the collection of KAASSCHIETER, C. tenellus crassus has been included in C. sp. cf. C. tenellus (REUSS) by this author.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member. Lede Formation.

Cibicides tallahatensis BANDY, 1949 + 1949 Cibicides tallahatensis Bandy- BANDY, p. 110, pl. 20, figs. Sa - c. 1970 Cibicides tallahatensis BANDY - LE CALVEZ, p. 184, pl. 40, fig. 3.

Remarks This species resembles C. westi, but differs from it because of the umbilical knob and the limbate dorsal sutures.

Occurrence : Lede Formation Brussels Formation.

Cibicides tenellus tenellus (REUSS, I86S) + 1865 Truncatulina tenellus Reuss- REUSS, p. 477, pl. S, fig. 6. v 1961 Cibicides sp. cf. C. tenellus (REUSS) - KAASSCHIETER, p. 219, pl. 14, figs. 2a- c. 1974 Cibicides tenellus (Reuss) - MURRAY & WRIGHT, pl. 16, figs . I 2 - 14 .

Remarks The umbilicus of C. tenellus tenellus is filled up with a glassy knob. The number of chambers in the last whorl varies from 9 to 13. The sutures become strongly recurved near the periphery. Some specimens have a more inflated last chamber. Variation is observed in the size of the umbilical knob, in the convexity of the test and in the rounding of the periphery. - 4:> -

Occurrence Asse Formation : Wemrnel Sands Member, Asse Clay Member Lede Formation Brussels Formation Panisel Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Cibicides westi HOWE, 1939 + 1939 Cibicides westi Howe -HOWE, p. 88, pl. 13, figs. 20 - 22 (fide ELLIS & MESSINA) v 1961 Cibicides westi HOWE - KAASSCHIETER, p. 218, pl. 13, figs. 6a - 7c. 1970 Cibicides westi Howe - LE CALVEZ, p. 184, pl. 43, fig. 9. 1974 Cibicides westi Howe- MURRAY & WRIGHT, pl. 17, figs. 3- 5.

Remarks Our specimens lack the deep umbilical cavity as figured by HOWE (1939). C. westi resembles C. tallahatensis BANDY, 1949, but differs from it because of the more split-like aperture and the absence of an umbo.

Occurrence : Asse Formation : Asse Clay Member, Wemmel Sands Member Lede Formation Brussels Formation. Panisel Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member. - 46 -

Superfamily Cassidulinacea d'ORBIGNY, 1839

Family Loxostomidae LOEBLICH & TAPPAN, 1962 Genus Loxostomum EHRENBERG, 18S4 Loxostomum teretum CUSHMAN, 1936 + 1936 Lo.xostomum teretum Cushman - CUSHMAN, p. 60, pl. 8, fig. 14 v 1961 Loxostomum teretum Cushman - KAASSCHIETER, p. 19S, pl. 9, fig. 20 1970 Loxostomum teretum CUSHMAN - LE CALVEZ, p. 132, pl. 24, figs. 2 - 3.

Remarks Our specimens have a finely perforated wall and limbate sutures. Some individuals have a very elongated test. Occurrence : Asse Formation : Asse Clay Member

Family Nonjonoclae SCHULZE, 18S4 Subfamily Noniorddae SCHULZE, 18S4 Genus Nonion DE MONTFORT, 1808 Nonion affine (REUSS, 18S1) + 18Sl Nonionina affinis m. - REUSS, p. 72, pl. S, fig. 32 v 1961 Nonion affine (REUSS) - KAASSCHIETER, p. 203, pl. 9, figs. 3 - 4 1970 Nonion affine (Reuss) - LE CALVEZ, p. 190, pl. 27, fig. 2.

Remarks Specimens of which the umbilicus is filled up with glassymaterial resemble N. chapopotensis (COLE, 1928). The convexity of the test varies.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation. Brussels Formation Panisel Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Nonion graniferum (TERQUEM, 1882) + 1882 Nonionina granifera, Terq. - TERQUEM, p. 42, pl. 2 figs. 8 - 9. v 1961 Nonion graniferum (TERQUEM) - KAASSCHIETER, p. 204, pl. 10, figs. !Sa - b. 1970 Nonion graniferum (Terquem) - LE CALVEZ, p. 192, pl. 26, fig. S. 1974 Nonion graniferum (Terquem)- MURRAY & WRIGHT, p. 11S, pl. 17, figs. 7 - 8.

Remarks : The granular material sometimes extends along the depressed sutures.

Occurrence : Lede Formation.

Nonior. scaphum (FICHTEL & MOLL, 1798) + 1798 Nautilus scapha Fichtel & Moll - FICHTEL & MOLL, p. 10S, pl. 19, figs. d - f (fide ELLIS & MESSINA) 1846 Nonionina communis d'Orbigny - d'ORBIGNY, p. 106, pl. S, figs. 6 - 7. v 1961 Nonion scaphum (Fichtel & Moll) - KAASSCHIETER, p. 204, pl. 10, figs. 14a - b, pl. 11, figs. Sa -b. 1970 Nonion commune (d'ORBIGNY) - LE CALVEZ, p. 191, pl. 27, fig. S. - b7 -

Remarks Specimens of which the umbilicus is filled up with granular mate­ rial, have not been observed in our material.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Genus Nonionella CUSHMAN, 1926 Nonionella spissa CUSHMAN, 1931 + 1931 Nonionella hantkeni (CUSHMAN & APPLIN) var. spissa Cushman nov. var. -CUSHMAN, p. 58, pl. 7, fig. 13. v 1961 Nonionella spissa CUSHMAN- KAASSCHIETER, p. 205, pl. 11, figs. 7 - 8. 1970 Nonionella cf. spissa CUSHMAN - LE GALVEZ, p. 194 1974 Nonionella spissa Cushman - MURRAY & WRIGHT, p. 120, pl. 18, figs. 6, 7, 9.

Remarks : Our specimens show a typical broad umbilical cavity.

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation leper Formation : Flanders Clay Member.

Nonionella wemmellensis KAASSCHIETER, 1961 v + 1961 Nonionella wemmellensis nov. sp. - KAASSCHIETER, p. 205, pl. 11, fig. 7 1970 Nonionella wemmellensis KAASSCHIETER- LE GALVEZ, p. 194, pl. 27, fig. 7. 1974 Nonionella cf. ? wemmellensis Kaasschieter- MURRAY & WRIGHT, pl. 18, figs. 10 - 11.

Remarks : The test is distinctly compressed and the lateral sides are parallel.

Occurrence : Asse Formation : Wemmel Sands Member, Lede Formation

Family Alabaminidae HOFKER, 1951 Genus Alabamina TOULMIN, 1941 Alabamina obtusa BURROWS & HOLLAND, 1897 + 1897 Pulvinulina exigua (Brady) var. obtusa BURROWS & HOLLAND - BURROWS & HOLLAND, p. 40, pl. 2, fig. 25 - 30 v 1961 Alabamina obtusa (BURROWS & HOLLAND) - KAASSCHIETER, p. 227, pl. 13, fig. 15. 1974 Alabamina obtusa (Burrows & Holland)- MURRAY & WRIGHT, p. 116, pl. 19, figs. 1 - 2.

Remarks The convexity of the dorsal side varies and the periphery is more or less lobate. The apertural face of our specimens is distinctly declined.

Occurrence : Asse Formation Wemmel Sands Member, Asse Clay Member. - 48 -

Alabamina wolterstorffi (FRANKE, I925) + I925 Rotalia wolterstorffi Franke- FRANKE, p. 186, pl. 6, fig. 6b. v 1961 Alabamina wolterstorffi (FRANKE) - KAASSCHIETER, p. 228, pl p 1. 14, fig. I 3a - e.

Remarks Besides typical specimens with rather acute periphery, individuals with a more rounded periphery occur. They can be considered as transitional forms to A. obtusa (BURROWS & HOLLAND, 1897).

Occurrence : Brussels Formation.

Genus Gyroidina d'ORBIGNY, 1826 Gyroidina octocamerata CUSHMAN & HANNA, 1927 + 1927 Gyroidina soldanii d'Orbigny var. octocamerata Cushman & Hanna - CUSHMAN & HANNA, p. 223, pl. 14, figs. 6 - 18. v 196 I Gyroidina octocamerata CUSHMAN and HANNA - KAASSCHlETEP. p. 212, pl. 13, figs. 2a - c. I970 Gyroidina octocamerata CUSHMAN & HANNA- LE CALVEZ, p. 95, pl. 42, figs. 4 - 5.

Remarks As mentioned by KAASSCHIETER (196I), this species differs from G. nngustiumbi1icata TEN DAM, I944 in its more rounded periphery and its deeper umbilicus. Our specimens show rather ·indistinct sutures.

Occurrence : Lede Formation Brussels Formation

Family Anomalinidae CUSHMAN, 1927 Subfamily Anomalininae CUSH~fAN, 1927 Genus Anomalina d'ORBIGNY, 1826 Anomalina acuta PLUMMER, 1926 + 1926 Anomalina ammonoides (Reuss) var. acuta Plummer - PLUMMER, p. 149, pl. IG, fig. 2 (fide ELLIS & ~1ESSINA) v 196I Anomalina acuta PLUMMER - KAASSCHIETER, p. 2I6, pl. 12, figs. 12- I7, pl. 8, fig. 9. I970 Anomalina acuta PLU~~R - LE CALVEZ, p. I97 1974 Anomalina acuta Plummer- MURRAY & WRIGHT, p. 116, pl. I9, figs. 3, 4, 7

Remarks Our specimens typically have 10 to 15 chambers 1n the last whorl. Specimens with less chambers in the last whorl are known as A. acuta var. ypresiensis (BROTZEN, 1948).

Occurrence : leper Formation : Flanders Clay Member, Mons-en-Pevele Sands Member.

Anomalina parvula GRZYBOWSKI, 1896 + 1896 Anomalina parvula Grzybowski- GRZYBOWSKI, p. 302, pl. 11, fig. 6a- b. (fide ELLIS & MESSINA). 1970 Anomalina parvula GRZYBOWSKI - LE CALVEZ, p. 198, pl. 44, fig. I I. I974 Anomalina parvula Grzybowski- MURRAY & WRIGHT, p. II6, pl. 13, figs. 14 - I5. - 49 -

Occurrence : Lede Formation.

Genus Hanzawaia ASANO, 1944 Hanzawaia boueana d'ORBIGNY, 1882 + 1882 Truncatulina boueana d'ORBIGNY - d'ORBIGNY, p. 169, pl. 9, .figs. 24 - 26. 1958 Hanzawaia boueana (d'ORBIGNY) - BATJES, p. 154, pl. 8, fig. Sa - c.

Remarks Our specimens have at least 9 chambers in the final whorl. The final chamber is more or less inflated.

Occurrence : Lede Formation Brussels Formation

Hanzawaia producta (TERQUEM, 1882) + 1882 Truncatulina producta Terq. - TERQUEM, p. 92, pl. 9, figs. 20 - 21 v 1961 Hanzawaia producta (TERQUEM) - KAASSCHIETER, p. 266, pl. 12, fig. 13. 1970 Hanzawaia producta (TERQUEM) - LE CALVEZ, p. 210, pl. 44, fig fig. 3, 9.

Remarks Most of our specimens have 6 to 8 chambers in the last whorl. Specimens with more chambers (9 to 10) in the lgst whorl and a smaller umbilicus belong to H. boueana (d'ORBIGNY, 1846).

Occurrence : Panisel Formation.

Family Ceratobuliminidae CUSHMAN, 1927 Subfamily Ceratobul imininae CUSHHAN, 192 7 Genus Lamarckina BERTHELIN, 1881 Lamarckina cristellaroides, 1882 + 1882 Rotalina cristellaroides Terq. - TERQUEM, p. 57, pl. 3, fig. 15a - c. v 1961 Lamarckina cristellaroides (TERQUEM) - KAASSCHIETER, p. 231, p 1. 15 , fig. 34. 1970 Lamarckina cristellaroides (TERQUEM) - LE CALVEZ, p. 203, pl. 37, fig. 4. 1974 Lamarckina cristellaroides (Terquem) - MURRAY & WRIGHT, n° 14, p. 119.

Remarks We did not find specimens with small spines on the dorsal side as recorded by KAASSCHIETER (1961).

Occurrence : Asse Formation : Wemmel Sands Member, Asse Clay Member Lede Formation Brussels Formation. - <;() -

Bibliography.

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BATJES, D.A.J. 1958 Foraminifera of the Oligocene of Belgium. Mem. Inst. R. Sc. Nat. Belg., nr. 143, 1-188, 13 pl.

BERMUDEZ, P.J. 1952 : Estudio sistematico de los foraminiferos rotaliiformes. Bol. Geol., Vol. 2, nr. 4, 7-230.

BROTZEN, F. 1948 : The Swedish Paleocene and its Foraminiferal Fauna. S.G.U., ser. C, nr. 493, text-figs. 41, 1-140, 19 pl.

BURROWS, H.W. & HOLLAND, R. 1897 : The Foraminiferal of the Thanet Beds of Pegwell Bay~ Geol. Assoc., Prov. London, England. (fide ELLIS & MESSINA).

CUSHMAN, J.A. 1922 The Foraminifera of the Byram calcareous marl at Byram, Mississippi. U.S. Geol. Surv., Prof. Paper, nr. 129-E : 123-152, pl. 29-35. 1931 Three new Upper Eocene Foraminifera. Contrib. Cushman Lab. Foram. Res., vol. 7, pt. 3, pp. 58-59. 1936 New genera and species of the Families Verneuilinidae and Valvu­ linidae of the Subfamily Virgulininae. Cushm. Lab. Foram. Res., Spec. Publ., nr. 6. 1939 A Monograph of the Foraminiferal Family Nonionidae. Geol. Survey, Prof. Paper 191, 1-100, 20 pl.

CUSHMAN, J.A. & PONTON, G.M. 1932 : An Eocene Foraminiferal Fauna of Wilcox Age from Alabama. Contrib. Cushman Lab. Foram. Research, val. 8, pts. 3-4, nr. 122, 51-73, pl. 7-9.

FICHTEL, L. von & MOLL, J.P.C. von 1878 : Testacea microscopica aliaque minuta ex generibus Argonauta et Nautilus. Wien Osterreich, Camesina, p. 108 (fide ELLIS & MESSINA).

FRANKE, A. , 1925 Die Foraminiferen des Norddeutschen Unter Oligocans mit besonderer Berucksichtigung der Funde an der Fritz-Ebert-Brucke in Magdeburg. Mus. Natur-Heimat-kunde, Naturw. Ver. Abh. Ber., Magdeburg, Deutschland, Bd. 4, Heft 2, S. 186. - 51 -

GUERIN-MENEVILLE, F.E. 1843 : Iconographie du Regne Animal de G. Cuvier. Paris, France, J.B. Bailliere, Mollusques (fide ELLIS & MESSINA).

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TERQUEM, M. 1878 : Les Foraminiferes et les Entomostraces - Ostracodes du Pliocene superieur de l'Ile de Rhodes. Soc. Geol. France, Mem., ser. 3, t.l, nr. 3. 1882 Les Foraminiferes de l'Eocene des Environs de Paris. Mem. Soc. Geol. Fr., ser. 3, vol. 2, 1-193, 20 pl.

WALKER, G. & JACOB, E. 1798 Adam's Essays on the microscope. Ed. 2, London, England (fide ELLIS & MESSINA).

WILLIAMSON, W.C. 1858 : On the Recent Foraminifera of Great Britian. Roy. Soc., London, England (fide ELLIS & MESSINA).

WALTON, W.R. 1964 Recent Foraminiferal Ecology and Paleoecology. In IMBRIE & NEWELL, Approaches to Paleoecology, 151-237, 31 figs. ------,I I I I I I I I I I I I I I I I I I I I I Ill .8 I I I ,c: I 0." ; I o e I .!!I N" 'ii I 'ii • Ill 0. Ill I 0 :J :.::. ... I olD I I I

e t1l w" g:" . 2 . D" N" a. d E

d u 0 ....J

0\ u.. Depth Log Samples Lithostratigraphy in m

17

18

19

20

21

22

23

24 : ~ 27 25 .q ·I 26 . I zs 26 .. : I 24 . .. . ·.. . ·.· . I 23 :· :. ~· ·:. I 22 27 .'. ~ .' ..:.-.'·• 21 , , , , I 20 28 ·.', ·.' ,'·. :·· I 19 ·. · ·. · ·.. I 18 ~ ... ·>.·~· .. :~·,17 29 .· . .~. ·~. I 16 i:~'J . , K, ItS 30 .• ·..... ··. ,,,4 z . 13 0 31 ...... -~ ...... ;. . . . I12 1- <{ X .:."·· ·.:-·.·. ·· · .· ·.•· · ·· ·.•. · I~ ,, 9 32 0:: ••t:.. e. :- c. .·, 78 0 ~ c ~ II u.. 33 ILl 34 0 ILl

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36

Fig. 2 Description of well n° 28 at Zemst.

(After the archives of the Belgian Geological Survey) 0 It) It) (',! ~ .... 41 40 ___} 39 ---- 38 >J <::_/ 37 < D 36 35 34 33 32 31 30 29 c 28 27 26 25 24 ' 23 22 2 1 20 1 9 1 8 1 7 1 6 15 8 14 13 12 1 1 10 9 8 7 6 5 4 3 A 2 1 0 ....0 CON 0 ...... coco 0....

F1g 2a Grainsize analysis of the samples from well n° 28 at Zemst. - ' . !\\IIIII

, ; 11 I ·--' }N- .. .. 'ilillll!l~ I ...,_ ,, I - - ~ - ~ ~ -: ir- ... - ... ·I :J ...... ; an- r--l , c-., ~ ~ "' ..'~ U') -- I ;li fD- ~ \ ~ \\ I - c.oN ... I + \ \r'\ r--- I ,I - ~ ~ r-. \ ~ «:! : I liD- ~ \ - I I .,._ r--.... ~ t:- ' r"l~ I I ftl = ... " 1'- i ~ - g.... -Sa- [\ ...... , t"\.. ~....

"\~ J """:! ... ·~ ~ ~·~ "~ " ~ ' \ A~- - I ~ 0 N ...... ~ + 1'- ~ iii ~ t'--..... ~~~ C"t - 1'- r-- -...... :: ~ ~ ~ .... en ill 'I ~ ..... ~ ~ lA.- ("f") ...... 1~LJl ._ ill !'-.. ~ ~ ~1 ~ Ill ... ~ ,, I - ~ ~~ ...... ~\'"T - + - O't m fD- I 0 r--- r...... I - -- \ a ·- ~ - 0 ·- r--, e . r i--. ~ m -- ...... ~- r- r--...... ~ lti- ... '\·~ ' ·~f- - Wl N-I I - -

Fig 2b Grainsize analysis of some selected samples from well n° 28 at Zemst. Oepth Outcrop Samples Lithostratigraphy in m

15.00

15 (8154)

15.50 14 ( 8153)

13 ( 8 152) a: w 16 00 12 ( 8 151) lD ;:[ w ;:[ 11 ( 8 150) z 0 > - < 10 (8 149) 1- ..J 16.50 < u ;:[ a: 9 ( 8 148) w 0

7 ( B 146)

17.50 6 (B 145) < a: w lD 5 ( 8 144) ;:[ w ;:[

18.00 4 (8 143) Vl 0z < 3 ( B 142)

Fig. 3 Temporary outcrop at Zemst. Fig 4 : Studied profiles in the quarry at Haasrode Profile N1 Samples Profile N2 Samples Profile N3 Samples lit~ostratigraphy

...:

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6 I'. . 'I. t10 0z 5 9 ;:

8 ~ 7 «

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Fig 5 Studied profiles in the quarry at Nederokkerzeel. Outcrop Samples Lithostratigraphy

Fig. 6 Lithological description of the Ampe quarry. Log Log Log Log 240 239 237 235

0 0

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-20

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Fig 7 : Lithological description of the wells at Zeebrugge. L eve I Miliolacea indet spp .., 0 a carinate I I I I ·I I I I oou9oo T angularis -1 l> C. t tenellus CD •m

0 c l>z S t. belgica -1 :::j )> "'0 R limbata -1 < m "'0 B. selseyensis 0 iii "'0 T agglutinans -1 :::0 ~~u-! oog r:nooooouoouoou-: ijj I I I I I U I "'0 P burlingtonens1s ~ I I b luuuooouoouuou I 1 I I I 1 B. anglica 0 I ... l I 4 ouuu~uuuuu I z G g. gravida 0 r u~-oo~-umoum uu\4 ! CJ u ., c-fr ou-1u~udououuuuuob~ouu u u uuuouluooou G. g. g1bba CD I I I I ' m ~ I ~ l I I I I I I I I G. irregularts z u { u uu au u u u u u up 0 u u a ul 0 0 0 0 -1 a 10 a a q :r I 1 I I I I A. bartoniana 0 0 0 0 u u u u 0 u u u u i 0 0 0 0 0 u 0 0 0 u a u o!u 0 0 0 0 z p q 4- r 0 C.t crassus I I I ., I 1 I 0 I I I :::0 I 1 I )> I I I I I I ~ II I I I I I I z I \ I I :;; i C. dutemplei m : u 4 ... ~ 0 u 0 0 0 0 0 0 0 u 0 u UF 0 0 0 0 :::0 i q 0 )> I I I. I I N affine I I z I I I I ~ I I I I m I I I • I I I • uJ uuuu G g punctate 1'. r:uooouooououooup N I I I S c. deperdita CID '1 o o 6 1u ... u u .. u u u u "I I I I I I )> I I I I I C lobatulus -1 I '*' ...... I I ""u ul I I I 0 uo 0 N 1 I I m B.cooke1 ~ T. wilcoxens1s VI -1 Ksiphonella

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C lobatulus -1 l5 '-' ~ w )> uuouuuuuuuuuuuuu u uuuuuuu u ,-CD ,., C. mauricensis 0 0 0 0 c 0 t::l 0 0 0 c t::l c \.1'1 0 "' 0 C p. proprius u u w p C p. acutimargo c 0 0 0 D 0 0 0 0 0 D 0 D 0 0 0 0 )> 0 0 0 0 0 0 r-u· 0 C pygmeus :z 1--· L.J -1 =i C tallahatensis )> u u u u u u u u u u u u <-1 u u m ~ ~ C) Vl l5 - -1 a;:0 C t tenellus c: u u u u -1 5 ~ u ~ u ~ :z ~ 0 w -n 0 - CD ,., ·= C westi :z TJ u -1 U U :I: 0z ~ ~ ~ ~ ~ ~ u~ ?i -n E laeve 0 0 0 :0 u u u u D 0 D D 0 0 D 0 0 D 0 0 0 )> 0 0 0 0 0 0 :z ~ ~ w G irregulans :.;;z = ,., G octocamerata u w w w w u u ..... '-' LJ w '-' -~ H boueana z u u u u u 1J 0 0 D 0 0 D 0 0 0 0 D D 0 0 0 0 ~ 0 0 0 l cnstellaro1des .... u ":0 0-n .... N affme ;= m -.::r N scaphum P burlmgtonens1s z u u w w

- w u· a carmata --cr---- Q. crassa

u----- Q costata

·-- l:::r·u-t::r··--· Q ludw1g1

------Q semmulum -·------0 0 0 R llmbata -·------··- u 0 u---·- R terquem1 ----·------·--·--·-- [JU ------·------·-----···· ·-----·--· ---·------. ·- ·- ---- . ---··· -- ·-·-·- -· -·-u------R andoum1 T agglutmans ·------··- ·-· ------.. ------... ------·-. - u -· -· T mural1s 1-----· . ------· ·------· . - •.. - . -· ------. u ··- T wllcoxenSIS ·------'CT---- U~!------··-·-T:r ------. I -,- I I I I I .. I I T I T I I I I I l I I I I I I I L (' V(' I

- Astengerina u u u UTI 1T Bolivina -I u u )> u u ,.....CD u m Cibicides

0 ~z -I ::::j )> -I ,..,< 0 Vi -I ::0 a; c -I 5 :z ,0 m ~ -I Elph1dium ::r :z0 U~UUTI-OITTITIITUUUUUUU~ u uuuuuuu ,r; 0 Globulina ::0 u LT LT )> 3: Guttutina z u u u u ::;;,.., u u u u u ::0 Gyroidma ,.....)> u u u u 0 0 0 0 0 0 0 0 0 0 Cl Hanzawoia ,.., 0 :z,.., ~ ~ 0 0 0 0 ~ ~ o o 0 ~ - ~ ~ ~ ~ ~ urru~ ~ ~ o ~ ~ z Non ion u u ::0 u "0 , Planulina ,..,;= u u u Quinqueloculina z u u u ~ u

Tr1farina u u u u -I 7 I I I L eve I

A tatumi ~

A spp u u u 8 selseyens•s u crenulata u 8 c car malus u u IJ u

N "' c lobatulus TI u.u u U u -u c mauricens1s "' p acut1margo -I c )> u til ,.,r­ c tallahatensis ~ ~ ~ ~ u p c )> z N -I "' c t tenellus :::j u IT u --u --u )> -I <5 li C westi ,.,< u u u u u u 0 "' E laeve ill u -I u u u ::0 5 ffi G. g gibba c u u -I 5 "' G. gravida z u ,0 "' H boucana u 0 til ,., 6 ~ ~ z ~ Miliolacea undet. spp. -I :X: lJ 0z ;::; , 0 ~ ::0 N. affine )> u ~ z "' N. scaphum ,.,:;; u u ::0 "' P. burlingtonens•s )> u "' a. carina Ia z u -u u ""0 "' Q. costata ,~ -.::r ;= "' Q. juleana ITI 0 0 0 0 "' Q. ludw1g1 --cr u -= -u "' Q. semmulum lJ u .... u "' u -.:r Q str~ata "' R terquem• u "' u u "' S canallculata u "' S t belg1ca u u "' S. t tricarinata u

"' T agglutinans u "' --u T gibba "' -o T wJ!coxens•s "' Lev e I

A. parvula

A. tatumi

A spp

8. selseyensis

8. anghca

B. car

8. crenulata

'" C car~natus

-1 )> ~ ,....CD c lobatulus I'T1 01) 0 c mauricensis p c '" c p. acutimargo )> z "' -1 c tallahatensis =i )> -1

CD "' G. lac tea zI'T1 -1 Ul :r: G. octocamerata 0z ;:; "' H. boucana '"TI 0 ;o 0 )> Miliolacea undet. · spp 3: ::;;z I'T1 ;o )> z ~ N affine "0 ;o U1 0 N. graniferum '"TI r= Ul I'T1 N. scaphum z U1 w N. spissa

"' N. wemmelensis

"' p burlmgtonens1s

<.11 a car~ nata

U1 a cost ala

a juleana

U1 a ludwigi

Ul a seminulum

"' a striata

Ul R terquem•

Ul R andoum• I I I I I I I I _1 J I L e vr I

Anomolona 1.1~

A,sterigerina ~u U LJ u u u Bitar ina u u u u u ... u

Bolivina ... u 0 u 0 LJ u u u u u u Cibicides p c >z -1 =i > -1 ,..,< 0 Vi -1 ;;o ~ -1 Elphidium 0 u u u u z u u u u u u ~ u u u ,0 Globulina ,.,t:D u u u u L::TTI u u z -t Gultulina :r: u u u u 0 z Hanzawaia ?i u u u u , lJUUu~u ~ u 0 u ;;o Lamarck ina )> u 3 u u u u u u u u u z ,.,=n u Miliolacea undet. spp. ;;o )> r- ,.,CI ,..,z ;;o )> Non ton z u u u u lJ u u u ;8 Ptanu!ina u u u u ~ ;= Quonqueloculina m u u u VI u u u u u u ~ TI u ~ u u z N

)> Reussella z u u u 0 Rotalia z u u u u u u u 1..\1 Spo rolocu I on a u l:f u u u u . Textularia Trifarina u ..... u TI u u Trtloculona u N C· N w I _L I I_ I l. I I

)> ];> 1> 1> 1> )> 1> )> J> IJ> )> )> )> ];> )> )> ~ ~ N ~ ... '-" "" h "' "" 0 1;::; w ~ <:n 0. :::; a; _L I I I I I II I I I ~ I I I I I I J. Level I I L Lexagona u u u I u : : T mural•s I I u u I C I tenellus u u I u u iU U U u I u I I ~ I I ~ ~ C westi w ~ u I u u I C lobatulus I u u ·~ I u I I:~ ~ ~ I I I I I I C carmatus u w u I : C p. proprius ~ I u u w u I u ~ I ~ ~ ~ I I I I I T a abbreviata I u u I I I G lactea u u I u :u G nregularis ~ ~ u jU I 0 0 I 0 I G. problema u u I u :u I I G g.g1bba u lu I u I I G g gravida u IU I A.acuta u iu u u u u w w I N. scaphum w w u I u u u u I w ~ u I u I I N affine u lo 0 I 0 0 0 I 0 0 I u 0 I I N spissa 0 u I I u P burlingtonensis u I I u Asp u u I I Asp. cf. A. g\Jerrana w u I I R andouini u I I u I I I u 8 parisiensis u u I L.J I u u I C subconicus w I I R. terquemi -u· I I I E laeve u I u : u I u u I u I u I Sp C. deperdita u I I 8 angllca u w I I u I u I u ~ I I I !: I I 0 "l1 z r- I I VI !: I !: I m 0 l> I m VI m !: r z I l> z l> 0 I !: I CD I CD z m -< m I I m 0 1) ::0 ::0 I VI m VI I ::0 I m< I I r- I I m "'w "' "' I ?' 1> 1> 1> l,. 1> 1> 1> 1> !: ~ j"f' .t : ~ m :: 15 ~ I;;) :f ~ Ill " "' '" Sampl• numb•r I I l hexagona ~ U- - l : T muralts - u u I I C tenellus u 0 I 0 0 0 0 0 0 I 0 ~ I I ~ ~ J I C westi u - u ~ u : l C lobutulus u I u u I I u ~ ~ ~ 1 p I ~ c: I > I I z I C. carinatus -f u ::j u u I I > C. proprius -f - u U I ~ u I <,.., u I ~ u ~ I ~ I 0 I iii I -f I T a. abbreviata ::0 o; u u c: ! l G.lactea -f u u - I u 25 - I z .1. G. irregularis - - u I u I u u 0 u .., I I G. problema u i u l u ~ i G g.gibba z u -f - I I u 5 I G. g. gravida ~ u ,.... - --+I A. acuta 0 0 0 0 D u u .., : - N. scaphum 0 u u 0 ~ U I 0 3: u ~ ~ u 0 u z I I N affone ,..,=n u u u u ::0 u :.. u u : u u u r- .l N. spissa u u ,..,Cl I P burtingtonensis z u I u ,.., - A. spp. ::0 u I u > I A. sp. ct. A. guerrai u - z I I R. audouini u -f u :X: I I ,.., I u I B. parisiensis > u u ~ I u u : - C. subconicus ,.., u I "' I R. terquemi g I - I E.laeve > u ~ u ::0 I I ::0 u u u -< I -U I I S. caronata deperdita )> u -f I j_ B.anglica u I - u I I u ~ I -n I 3:: r- I 0 )> I z 3:: z I Ul 0 m m I I m' 3:: I a:J ::tJ z m Ul I I 3:: ' ;;o m -o (") I 3:: m r- I I < )> ID m m r- -< I I ;;o m I I Ul I I )> I z 0 Ul Sample number Level T agglutinans

l.hexagona

A. beccarii ...... N ~~ g I C. tenellus )> :z ~ :::::j , I : . )> ~ l I I C westi m< -t--,-,----~o~--'-: ------/--.,------

0 I Vi 'I ~ C proprius ;o --~----- 1 a; I c ----u---+--u·--..,...-!------C lobatulus ~ i5 1 :z I C lactea 0 "TI G. irregularis a:J m G. g.gibba :z ~ I :I: I :z0 ?i G. g. gravida "TI a. seminulum 0 ;o "'e------,-1"' I ------T--r..--- )> . ------r-----;c-i'T--- a. impressa 3: I i z I I I H. producta m=n I ;o 0 u I I )> I I P. burlingtonensis u I TJ z : E.laeve u I -u:o ~ _j_ I E. subnodosum m : ru r­ ---- E. minutum r- I u E. ungeri ::I 10 E. inflatum IJI F. marginata )> C subconicus ~ N m m E. schreibersi a:J ;o c Cl Cl m

Of. plankton

"TI 0 "'0 ::0 )> 3: z )>_, mVi 0 r­ z

"'0

-i )> OJ r- rrl ..... w Textu I an idae

0 c: )> z 0"' -i ::j )> -i Nodosariidae rrl< CJ Vi ~ -i A) Cib1cididae c:OJ -i 5 z "'0 0 -n OJ s rrlz -i :::J: 0 z Anomal.n1dae i=i -n i5 0 A) )> ~z -n rrl A) Epomdidae )> r- C'l rrlz 0"' rrl A) )> z Rotal•idae i5 ~ rrl r- r- Mil•ol1dae ::J 10 U1 ~ )> -i N rrl ..., Elphidi 1dae OJ A) c: i5 C'l ...,C'l

Oiscorbidae , 0 "'0 ;o l> ~ z l>..... Vim 6 z Sample number Level ·~ T. •991"'i~O$

l.hexagona

-1 ,...~ m A. beccarii

§ C. teneUus )> z -1 ~ <-1 m C. westi c

~ C. proprius

~ C. tobatulus ~ .,0 i G. irregularis ,ttl z G. gibba gibba -1 i;=; ..,· Q. seminulum

~ Q. impressa

!m H. producta ~ z P. burlingtdnensis E.laeve ,.,~ ,... E · subnodosum ,... E. minutum :;, 10 E. ungeri CD )> -1 C. subconicus N m ~ u-- E. schreibersi c: I I I ~ I I - I T. wilcox.ensis ---+------~ I

~--~-- N. affine B. parisiensis ------:I ------

"1. plankton 0 0 "U )> z iii m r- ... "'.. "' "' "'.... "' "'

-I )> "'0 Elphidtidae CD r- m i5 ...... U'1 c c )> Textulariidae z -I -I )> 0"' -I :::t z !:; ,..,=n ::0 )> m r- 0 Anomalinidae ,..,Cl z i5 m ::0 )> Milioltdae z "' ,..,~ r- Epontdtdae r- i'o C5 CD )> -I Rotalitdae ,..,N ,.., 6 CD ::0 c Cl Discorbidae Cl !'Tl i5 , 0 \) ;o )> :s:: z )> Vi -i m 6 r z w w w w w w ~ w a> "' .. "' " Sample number _:;:..,. Level

T aggtutmans

0"' E schreibers1

5 E spp A. beccari1

5 C t. tenellus ..... > CD 5 r C westi m a-~ i5 c tobatulus D c c p acutimargo >z ..... 5 mural1s =i > ..... i5 wilcoxens•s m< i5 0 Vi..... ::0 iii .....c 0 z 8 anglica 0-n i5 ,..,CD !':: z ..... ~ N affine :I: 0 z i5 i=i N. Sp15Sa -n 0 i5 ::0 > p 3: burlingtonensis :;;z "' 8 paris1ensis m ::0 "' C subconicus > z 5- ~ !':: m r F marginata r :;:) "' E minutum _.10 0 5 .....> L cris tellaroides S c. deperdita ,..,N m "' A spp CD ::0 c i5 C'l C'l !"''

U farinosa

"' A. obtusa "'

'1. plankton

~ m )> l: V> l: l: l: V> m m m m r- l: l: CD (") CD V> m r- m )> ::0 )> ::0 ~ z ::0 -< 0 V> m ~ :::: ::: ';! ::: Samplr numbrr Lrvr/

Cibicididae

N J 0 j sj I I Rotaliidae

..... tD Textulariidae r­ m

l!l p c: )> s z :j Miliolidae ..... )> !S ..... Nodosariidae :X :;;z m ::0 )> r- C'l mz m Discorbidae ::0 > z :t: m r­ r- Asterigerinidae :::1 10 ..... 0 .....)> N m m tD ::0 c: C'l C'l !'""' Nonionidae

Bagginidae :g !: N.. I;; ~ !; l:: & f: ~.. .. w Sample number ...... w !: & ~ ~ ~ ..:: ~ ~ * Lev e/ T. agglutinans

E. schreibersi

E. spp.

C tenellus -t )> ,...OJ C. xesti fTI ...... CD C lobatulus p c C. proprius )> z -t T. muralis :::j )> -t T. wilcoxensis

z~ ---- · tr --IJ~ ·· __ _j______--·-- · --~-- -- B. parisiens•s ::;; fTI C subconicus ::0 )>

N z 0 ~lrnt~ ~ F. marginata ,... u u lo olo 0 ,...'"" E. minutum :::l 10 ...... L. cristellaroides )> S.c. deperdita -t A. spp. N u-~-----·- fTI fTI OJ c::0 C'l C'l fTI U farinosa A obtusa

N 0

u------"/. plankton 0 0

l> l: (J) m Vl l: l: m m ID n l: m ,..... ID z ::n l> m (J) 0 l> :ii -< ::n z m CJ (J) ...... Q ., E ., :) ., ., "'0"' ., c: ., ·c: ., ., ., :"2"' "'0 "'0 ., ., c: ., ., ., "' "'0 .r:. "' "'0 ., "' ·c: "'0"' "'0 ... "' Q. "'0"' "'0 "' a; "'0 "'0 c: :"2"' c: "' ..a ""2"' "' "'0 "' ~ 0 :; c: <;!> c ~ :"2"' U'l - c: ""2 -;; u "' E "'0 a; a, 0 c:: 2 E ;;; 0 0 c: § ·~ u :. .0 K" "'0 Z:- 01 01 Ill ~ 0 c:: 111 ... 0 ., 0 0 <( UJ V) ...... u a:: 1- :i z ll.. t5 alal ::l al 0 z I I 47 36 46 36.5 ---t--- ASSE CLAY 45 37 MEMBER 44 37,5

43 38 SANDE NOIRE 42 39

41 39.5

40 40 WEMMEL SANDS 39 4Q5 MEMBER 38 41

10 20 30 40 50 60 5 20 5 10 20 5 5 10 20 20 20 10 20 30 10 20 30 "C 20 30 10 20 30

TABLE19 : QUANTITATIVEDISTRIBUTION OF BENTHONICFORAMINIFERAL GENERA IN WELL n~11 AT ZEEBRUGGE.