Uwagi o stratygrafii kampanu i mastrychtu doliny środkowej Wisły

Abstract

REMARKS ON CAMPANIAN AND MAESTRICHTIAN STRATIGRAPHY OF THE MIDDLE VISTULA RIVER VALLEY (CENTRAL POLAND)SummaryThe author's subdivision of the Campanian and Maestrichtian deposits occurring the Middle Vistula River valley is shown in the Polish text, Tab. 1. However, the following supplements should be added to the scheme presented in the table: a) Eupachydiscus levyi (Gross.) has not been ascertained in the top portion of the beds of the horizon determined by the species under consideration; b) extent of Neancyloceras (?) phaleratum (G r i e p e n k.) et subsp. does not embrace, probably, the bottom portion of the beds of the unit determined by this form; c) the presented extents of Belemnitella junior Nowak and Pachydiscus neubergicus neubergicus H a u e r are for the most part, of compilatory character.In addition, the following remarks, broadly discussed in the Polish text, are worthy of being stressed here. In the presented scheme the boundary Santonian-Campanian runs at the bottom of the beds with Gonioteuthis granulata (Blainv.) f. typ. according to J. A. Jeletzky's conception (1955, 1958) and, approximately, also to F. Schmid's scheme (1959 b). Such a solution is supported by an analysis of the data concerning the relation between the extents of the group Gonioteuthis granulata (Blainv.) and of the group Diplacmoceras bidorsatum (R o e m.) thought to be index form of the lowermost part of the Campanian within the area of stratotype, where the group Gonioteuthis granulata (B l a i n v.) is lacking. A restriction of the extent of Bostrychoceras polyplocum (R o e m.) in the author's scheme, as compared with the extent known from the previous elaboration concerning the Vistula section and from the most part the European schemes, is a result of a narrower interpretation of this species, referring to the accepted systematics of Nostoceratidae (L. F. Spath, 1953; C. W. Wright, 1957; T. Matsumoto, 1959). It should here be stressed that the species Nostoceras (?) schloenbachi (Favre) linked up with the genus Bostrychoceras Hyatt is seen by the present author only in the Lower Maestrichtian. The specimens occurring in Campanian and linked with this species (N. P. Michaylow, 1951; D. P. Naydin, 1959, 1960) are thought by the author to be homoeomorphic forms connected with the group Cirroceras donezianum (Michaylow). The author stresses also that the stratigraphical position of the species that should be connected with the genera Cirroceras Conrad (= Didymocers Hyatt), Emperoceros Hyatt and Nostoceras Hyatt from the European areas, appears to be in line with the extents of these genera within the areas of the United States of North America (L. W. Stephenson, 1941; W. A. Cobban and J. B. Reeside, 1952; W. A. Cobban, 1958; K. Young, 1960; T. Birkelund, 1965). The position of Pachydiscus neubergicus (Hauer) in the author's scheme differs from that accepted to-day as a part of the present stratigraphical schemes (see also A. Błaszkiewicz, 1965).