Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 17. 1994. (Budapest, 1994)

FRAGMENTA MINERALOGICA ET PALAEONTOLOGICA 17. BUDAPEST, 1994. p. 5-70 Egerian plant fossils from Pomáz, Hungary by L. Hably Hably, L.: Egerian plant fossils from Pomáz, Hungary.- Fragm. Min. et Pal. 1994, 17: 5-70. Abstract: Pomáz is one of the best dated paleobotanical localities in the area of the Central Paratethys. According to nannoplankton studies the layer with the leaf remains belongs to the NP 25 Zone (Egerian, Late Oligocène). The flora represents a zonal vegetation because the proportion of the riparian elements is very low and the swamp elements are missing. The zonal vegetation consists of thermophilous elements, including laurophyllous evergreen and deciduous members. Daphnogene div. sp., Palaeocarya orsbergensis, Platanus fraxinifolia, Leguminosae div. sp. are characteristic and some of them are dominant. Arctotertiary elements are rare, except Ulmus pyramidalis which is abundant. All Arctotertiary elements are members of riparian vegetation. This means that their presence was controlled mainly by the edaphic conditions and not by the climate. Therefore, the zonal vegetation indicates a subtropical, humid climate. INTRODUCTION The paleobotanical site is situated in a gully at the foot of Mesélő Hill, near the village of Pomáz, in the so-called Kartálja area (Fig. 1). The first report on the outcrop, including a short list of its fauna, was published by A. Koch (1871). All the later authors were concerned only about the fauna of the exposure, except Báldi (1965), who reported also plant fossils, Sequoia and Cinnamomum, from the light yellow, fine-grained clay. According to A. NAGYMAROSY (pers. comm.), this fossiliferous layer contains a relatively poor nannoflora; however, one of its species, Helicopontosphaera recta, became extinct at the end of the nannoplankton Zone NP 25, while an other species, Triquetrorhabdulus carinatus, appeared only at the base of the nannoplankton Zone NP 25 at this latitude. Therefore the layer, in all probability, belongs to the nannoplankton Zone NP 25. The plant imprints that I collected from the layer are deposited in the Hungarian Natural History Museum, and the material includes more than 800 specimens. THE GEOLOGICAL DESCRIPTION OF THE LOCALITY The outcrop in Pomáz - Kartálja was studied by Báldi (1965, 1973). He determined the mollusc fauna and made a strati graphical revision. The succession of strata, from bottom to top, is the following (after Báldi 1973) (Fig. 2): 1. A friable, fine-grained sandstone. 2. A sandy clay with a Glycymeris latiradiata community, with some specimens of Polymesoda convexa accompanying the large Glycymeris latiradiata and Ostrea cyathula. 3. A friable micaceous sandstone with clay boulders. It contains a fauna very rich in specimens, including pulmonate gastropods and bone fragments.