Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 90. (Budapest 1998)

Bajzáth, J.: Plant macrofossils from the Hungarian Pleistocene III. Palaeobotanical study of Győrújfalu, Western Hungary

to the field observations and borhole data there are two forest layers or lenses in the calcareous sandy layer between 25 and 35 m. The upper woody layer contains mainly tree trunks and cones of coniferous trees (Larix sp., Picea abies, Pinus sylvestris). The lower layer is probably derived from mixed coniferous (same species as above) and deciduous trees (Alnusl, Salix?). (The wood remains has not been examined yet.) On the other hand the fine sandy layer contains detritus-rich clay boulders in the above mentioned depths (20, 25, 28, 30, 33 m). The black and brown clay boulders have been originated from lenses deposited very close to the present locality and formed presumably by the undercutting of meandering channels in a floodplain environment. This assumption is based on the field observations, borhole data suggesting a large quantity of compact, laminated structure of the clay deposits occuring at various depths. The palaeontological analysis of the clay material also supports this model. A detailed geological and palaeontological description of this site was given by JÁNOSSY & KROLOPP (1994). The palaeobotanical records was collected from the brown, black and light-blue coloured detritus-rich clay boulders and the plant macroremains were identified. EVIDENCE OF THE AGE The first important task is to clarify the age of the locality. Among the molluscs and vertebrates there are several extinct species, characteristic of the Lower Pleistocene series in Hungary. Based on the biostratigraphy of molluscs (KROLOPP 1983) the entire sequence between 20-35 m can be assigned to the upper part of the Viviparus boeckhi Biozone. The examination of the vertebrates produced independent age evidence. Palaeoloxodon antiquus FALCONER, 1845 together with Archidiskodon meridionalis meridionalis NESTI, 1825 and other formes, characteristic of the Lower Pleistocene series in Hungary. Examination of micro vertebrates provides further evidence about the exact stratigraphical position of Győrújfalu assemblage within the Hungarian Pleistocene. The presence of Mimomys savini HlNTON, 1910 together with Mimomys reich HlNTON, 1910, Desmana thermalis KORMOS, 1930 and Pitymys gregaloides HlNTON, 1923 indicates the upper part of the Lower Biharium. (Nagyharsányhegyian and Templomhegyian) within the Hungarian microstratigraphical series. The upper part of the sandy layer, may have been redeposited so the younger, Middle Pleistocene coarser sediment mixed with the older one between 20-24 m. A preliminary pollen analysis of the clay boulders sampled at 28, 30, 33 m proved the early interglacial age within the Hungarian Pleistocene (Zs. MEDZIHRADSZKY, pers. comm.). Some exotic elements, i.e. a significant amount of Tsuga pollen grains were indentured in the samples at 20 m. The pollen grains of Picea, Larix, Abies, Carpinus and Pinus were found in each sample. (The pollen analysis has not been completed yet.) Microfossil analysis of fluvial deposits from borehole cores from the Hungarian Great Plain was carried out several years ago (MlHÁLTZNÉ 1982, LŐRINCZ 1987). The pollen analysis (there was no macrofossil analysis) proved the existence of the exotic species in the mesocratic phase of Günz-Mindel interglacial. For example Pterocarya, Carya and Eucommia were identified in the core samples. In addition pollen grains of