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

Fig. 1 Locality map showing the areas studied and the distribution of the Middle Eocene rocks. Cross-hatched : Early Lutetian transgression, horizontally ruled: Late Lutetian transgression OUTLINES OF PALEOGEOGRAPHY After a long (Paleocene to Early Eocene) terrestrial epoch, the Middle Eocene transgression began in the western part of the Transdanubian Central Range (TCR). At the very beginning of the Lutetian (Nummulites iaevigatus Zone "w NP 14) the sea invaded this southwestern area rather quickly; its basal sediments overlap the Upper Triassic/Upper Cretaceous basement and local bauxite lenses. The northeastern part of the TCR was covered by the sea much later (after about four million years), in the time of the Nummulites perforatus Zone ( ~ NP 16). This considerable difference in time can be one of the main reasons of the contrasting development of the two areas. In an overall view, the Middle Eocene of these two areas give the impression of two different worlds. The sequences begin with thin (10-20 ml carbonaceous clay in the SW, whereas thick, brown-coal bearing sequences develop in large areas in the NE; the terrigenous elastics are shortly followed by pure, biogenic limestones of more than 100 m thickness in the SW, whereas clays and siltstones characterize the sequences in the NE; coarse terrigenous elastics are absent in the limestones and overlying pelitic rocks in the SW, whereas sands and sandstones are frequent in the higher part of the sequences in the NE. For a better understanding of the paleogeographical relationship between the twoareas, more sedimentological data would be needed from the transitional region (Northern Bakony).