Tithonian-Volgian ammonites from Brzostówka near Tomaszów Mazowiecki, Central Poland

Abstract

Described are ammonites collected in the classical section at Brzostówka, from deposits referable to the uppermost Lower Volgian (upper pseudoscythica Zone) and the lowermost Middle Volgian (lower scythicus Zone) on the one hand, and to the lowermost Upper Tithonian on the other. The ammonites belong to the genera Ilowaiskya, Pseudovirgatites, Isterites, Lemencia(?) and Zaraiskites. Four new species and three new subspecies are established. The ammonites from Brzostówka, which comprise several forms hitherto unknown from Poland, make it possible to recognize the genus Pseudovirgatites as ancestor of Zaraiskites, and to discuss some stratigraphical and biogeographical problems, concerning middle parts of the Tithonian and Volgian Stages in East-central Europe.