Graptolites from the Klabava Formation (Arenigian) of the Ordovician of Bohemia

Abstract

The Klabava Formation (Arenigian) of the Bohemian Ordovician in the western part of the Barrandian Paleozoic basin is developed in a clayey shale facies. Its thicknesses are in places great, but it is very poor in paleontologic material, except some horizons with relatively high fossil accumulations. Graptolites are the dominant faunal component in the Klabava Formation, and representatives of the other groups are rare. The graptolite fauna from the Klabava Formation was studied systematically by BOUCEK. In a number of less extensive papers (1932, 1933, 1944, 1956) he examined specimens collected from some of the sites which are now considered to be classical localities of graptolites in the Klabava Formation. In a monograph (1973) on the graptolites from the Lower Ordovician of Bohemia BOUGEK revised his previous studies of the Klabava Formation graptolites fauna and added new information obtained by studying a rich material from a number of boreholes drilled in the west Barrandian between the fifties and sixties. The material examined by BOUGEK (1973) is largely stored in the collection of the Geological Survey, Prague; and partly in the collection of the National Museum, Prague, and the Faculty of Natural SCience, Prague. In addition to the localities reported by BOUGEK (1973) from the Rokycany area in the centre of the western part of the Barrandian, there are several outcrops of clayey shale of the Klabava Formation which have yet escaped paleontologic attention. The systematic paleontologiC studies made by myself and my father on both these outcrops and BOUGEK'S classical localities during the last years permitted us tu obtain a rich graptolite material that gives a fairly comprehensive picture of the graptolite fauna in the Klabava Formation. This paper summarizes the results gained by examining the material just mentioned. It is supplemented by a study of the fossils from the boreholes drilled in the Volduchy a TMkov areas between 1970 and 1971. Also included are some remarkable graptolites recorded from the classical localities in the Klabava Formation from M. Mergl's private collection. The material dealt with in this paper is in the collection of the District Museum of Dr. B. Horak, Rokycany (abbrev. OMR).