Morfologia powierzchni rostrum i przekroju grzbietowo-brzusznego części alweolarnej belemnitów z rodzaju Belemnitella i Belemnella

Abstract

MORPHOLOGY OF ROSTRUM SURFACE AND OF DORSO-VENTRAL SECTION IN THE ALVEOLAR AREA OF BELEMNITES OF BOTH THE BELEMNITELLA AND THE BELEMNELLA GENERA Summary In the article the elements of morphology of rostrum surface and of dorso-ventral section of the alveolar area, as well as their appliance in determination of belemnites of both the Belemnitella and the Belemnella genera are discussed. The systematic division of both genera based on the T. Birkelund's (1957) and J.A. Jeletzky's (1951) system is given. The stratigraphical extents of individual forms are given also on the basis of the two authors said. Data concerning the occurrence of these forms are taken from the profile of the Upper Cretaceous in the Vistula reach area. Table I gives more important taxonomical elements for individual species and subspecies. Table II gives stratigraphical extents of individual forma of both the Belemnitella and the Belemnella genera. Table III gives subdivision of the Campian and the Maestrichtian of NE Belgium, on the basis of belemnites after F. Schmid (1959). This table is made in order to pay attention to the new possibilities in application of belemnites for stratigraphical purposes.