Dr. Nagy I. Zoltán szerk.: Fragmenta Mineralogica Et Palaentologica 5. 1974. (Budapest, 1974)
the northern area (SZTRÁKOS 1974a). Thus the so-called "Paleogene Line" marks the shore-line of the Eocene-Oligocène sea, rather than a tectonic feature. In the lower part of the Egerian Stage rocks of Kiscell Clay-type appear. In the southern foreland of the Bükk Mountains a limestone facies with an Upper Oligocène foraminiferal fauna, corresponding to that of Escornebéou (BUTT, 1966) can be recognized. Upwards in the profile more and more shallow - water, finally terrestrial sediments appear. THE DIFFICULTIES OF PLANCTONIC FORAMINIFERAL ZONATION In the past years it became obvious that the placktonic foraminifers do not provide the "magic key" to solve unequivocally and accurately all our stratigraphie problems. The unit of the zonation is the biozone, and its boundaries are marked by appearance and extinction data. Consequently the validity of the zones is limited by the distribution of the index species appearing in these zones. The Hungarian profiles have yielded several species with precisely recognizable evolution lineages, appearance and extinction data. Comparing the appearance and extinction data of the Hungarian Upper Eocene species to those of the Italian ones, there are no significant differences, because of the similar paleoclimate of the two regions. Thus the first evolutionary appearance of the Globige rina ampliapertura , G. ouachitaensis gnaucki , Turborotalia brevispira , and the extinction data of the Turborotalia aff. centralis, T. cerroazulensi s cocoaensis are in good agreement with the data given by BLOW (1969) and BAUMANN (1970). On the other hand, the species Globigerina tapuriensis appears at the Eocene / Oligocène boundary, according to BLOW (1969), while BERGGREN (1969b) and the present writer (SZTRÁKOS 1972) encocentered it in the Upper Eocene too. MARTINI, E. studied a sample (No. 63.) from the Buda Mounts, and in this material the species Globigerina tapuriensis was associated with Turborotalia increbescens, Globonomalina micra , Glo bigerina ampliapertura and G. ouachitaensis gnaucki . Additionally he determined the nannoplankton species Discoaster barbadiensis TAN SIN H OK and D. saipanensis BRAMLETTE et RIEDEL in the sample, and on the basis of the latter forms this sample can be ranged into the upper part of the Priabonian (MARTINI, E. , written communication). Consequently, the species Globigerina tapuriensis can be regarded as a form which appeared first in the northern, cooler areas, and later migrated towards tropical waters. The relatively fast migration can be due to the smaller climatic differences in the Eocene, as compared to those in the Oligocène. Fig. 2. Tabulation of the Hungarian Upper Paleogene formations, planktonic andnannoplanktonic zonations. 2. ábra. A magyarországi felső paleogén plankton és nannoplankton zónáinak táblázata.
