Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 90. (Budapest 1998)

Dulai, A.: Early Jurassic brachiopods from the basal layers of the Pisznice Limestone of Lábatlan (Gerecse Mts, Hungary)

THE LOCALITIES AND THEIR FAUNAS Tölgyhát quarry The topmost layers of the Upper Triassic Dachstein Limestone can be seen at the base of the classical Tölgyhát quarry, in about 3 meter thickness. This limestone is unconformably overlain by a thick, more or less continuous Jurassic section. The lowest formation of the Jurassic is the Pisznice Limestone, a reddish-grey, splinterly breaking limestone. Its microfacies is onkointrabiosparite with biomicrite mottles (KONDA 1988). The lower part of the formation is poorly layered and contains small intraclasts at some places. The fauna of this limestone includes crinoid fragments, benthic foraminifers, ostracods, brachiopods, gastropods and juvenile ammonoids seen only in polished or thin sections (KONDA 1988). Brachiopods are the only determinable megafossils in the basal layers of the Pisznice Limestone. According to KONDA (1988), these layers deposited in a high-energy environment. The age of this formation was determined by G. VÍGH (in KONQA 1988) as Middle Hettangian to Sinemurian, although no fossils were mentioned. The examined brachiopods were collected by the author from the lowest 3.5 meters of the Pisznice Limestone. This part of the formation is very thick-bedded and this part of the section can only be divided into two different layers (Fig. 2). The following brachiopod species were determined (the number of specimens is given in brackets): Layer 1 Calcirhynchia plicatissima (QUENSTEDT) Cuneirhynchia cartieri (OPPEL) (11) (3) (8) (1) (1) (1) (4) (1) (1) (2) (23) Rhynchonellida indet. Liospiriferina alpina (OPPEL) Liospiriferina guembeli (NEUMAYR) Spiriferida indet Phymatothyris aft. cerasulum (ZlTTEL) Zeilleria cf. alpina (GEYER) Zeillena mutabilis (OPPEL) Zeilleria choffati (HAAS) Terebratulida indet. Layer 2 Calcirhynchia plicatissima (QUENSTEDT) Cuneirhynchia cartieri (OPPEL) (1) (3) (13) (1) (6) (4) Rhynchonellida indet. Liospiriferina alpina (OPPEL) Spiriferida indet. Phymatothyris aff. cerasulum (ZlTTEL)