Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 14. 1989. (Budapest, 1989)

The starting point is a plain shore. The near-shore ebb and-flood is not especially favourable for the large benthos. Here only smaller faunas evolve under autochthonous conditions, most of the larger Foraminifera changes its place according to the tide. In the lagoontype gulfs and bays (that are not cut off from the open sea) a rich'larger Foraminifera fauna exist. Around the lagoons on the mild slopes of the reefs and shelfs facing the sea, the conditions are also favourable for larger Foraminifera. The water depth at these two latter habitats ranges to about 90 m. The well-transilluminated (important for the symbionts), warm water with a high energy and rich of oxygen, the bottom covered with many epiphytes (food and habitat), the loose caustic sludge coming from the weathering of the reefs and shelfs and the rather rich organic detritus it contains (nutrition) provide optimal living conditions for larger Foraminifera. The external shelf region, due to its greater depth, offers only a limited possibility for the evolving of larger Foraminifera faunas. Here the spherical forms disappear and the flat types predominant. These faunas evolve near to the margin of the continental slope. In case of steep slopes, however, due to the gravity force, they may get to the foot of the slope in forms of larger bulks or debris flow (olistolite, turbidits) and form an extraneous body in the environment. This depth-range model is well applicable for the Eocene larger Foraminifera of the Transdanubian Central Range, and thus provides the possibility of the reconstruction of depth conditions in the Eocene. Fossil equivalents of recent Nummulites, Operculina, Amphistegina, Borelis, Amphisorus, Sorites and Heterostegina can be found in large amounts in the Eocene fauna. Data of Nummulites, Operculina and Amphistegina can be deduced directly to the fossil equivalents. Borelis is related to Alveolina, while Sorites and Amphisorus to Orbitolites

. Data on Heterostegina may be applied to their closest relatives, the Eocene Operculina

. Only discocyclinids have no recent equivalents or relatives. These are fitted into our model of reconstruction on the basis of joint occurrence with some depth-indicating larger Foraminifera, and functional morphologic analogies. Based on the larger Foraminifera fauna of the selected sections, the following depth conditions can be reconstructed in the Transdanubian Central Range; The carbonate sediment sequence (Szőc Limestone) filling the lower part of the Lutetian stage was deposited by a sea transgression at the beginning of the Lutetian from SW, and rapidly penetrating towards NE it got up to Bakonybél. The sea quickly became stable and provided favourable conditions for the appearance of larger Foraminifera. The most frequent and most important forms of this rich fauna of great diversity are the Nummulites. Alveolina, Operculina, Discocy

clina and Orbitolites are also significant. Depth analysis based primarily on Nummulites indicates shallow marine environment, not exceeding the 200 m. The sedimentation matching the conditions of the external shelf region was continuous and steady. The warm, nutrient-rich sea of normal salinity existed for a long time, providing favourable conditions for the rapid evolution of Nummulites and Alveolina

. In the middle of the Lutetian, changes in the fauna and sedimentation may be observed. The larger Foraminifera fauna gradually decreases, then disappears, and the sedimentation turns into clacareous marl, ant then into clay. Simultaneously, in the increasingly pelitic sediments the amount of planktonic Foraminifera grows rapidly and at certain places it becomes almost rock-forming. This and the upwards increasing glauconite contents refer to the deepening of the sea. The pelitic sedimentation produced a rather thick sediment sequence, and the process was stopped by the Priabonian transgression. Depth conditions of the Priabonian sea are less known, since most of the Upper Eocene sediments were denuded. In the SW Bakony Mts., Priabonian sediments are known only from the deeper Halimba basin and from its neighbourhood. Such sediments can be found in the borehole Somlóvásárhely-1, represented by tuffitic sandstone. Its larger Foraminifera fauna indicates a shallow marine environment, reflecting depth conditions of the outer shelf region. Return of the transgression in the SW Bakony may be observed in the Upper Lutetian. The sea flooded the Zirc- Eplény basin, advanced toward NE, flooding the N margin of the; NE Bakony Mts. and also the Pusztavám-Oroszlány basin. At the bottom of the transgression sequence coal formations may be observed frequently. The larger Foraminifera fauna of the marine beds indicates first a shallow, and then a deeper marine environment. Determination of the depth is not easy, since the subsidence of the basin was not steady. Occasional bottom changes resulted in oscillation sequences, and their larger Foraminifera fauna indicates shal-