Szabó János szerk.: Fragmenta Mineralogica Et Palaentologica 19. 2001. (Budapest, 2001)

16 GALÁCZ, A. & banks of the Upper Triassic Dachstein Limestone, which are overlain by a ca. 20 m Lower Jurassic carbonate series ranged by KONDA into the Pisznice and Tűzkövesárok Formation, i.e. into the Sinemurian and Pliensbachian. The middle Lias sic layer is covered by some beds of the Toarcian Kisgerecse Marl. S/ \IÎO, J. The sequence in the southern quarry, which is the locality of the gastropods described here, is very similar. The uppermost 10 m of the exposed Dachstein Limestone is followed by the pinkish, massive beds of the Pisznice Limestone Formation. The 7 to 8 m thick carbonate series seems to represent the whole Sinemurian and Pliensbachian; characteristics of the Tűzkövesárok Formation cannot be identified. On top of the Pisznice Limestone the lower 3.3 m of the Kisgerecse Marl is exposed. Higher parts of the sequence are eroded. Here the Kisgerecse Marl is very clayey, with 1 to 3 cm calcareous nodules, while harder limestone beds are practically missing. In the present state the exposure would need extensive work for systematic, bed-by-bed collecting. However, the rich fossil material can be sampled from the slope debris, which covers the abandoned face of the old quarry. Ammonites are very abundant: the Lower and Middle Toarcian are represented with Dactylioceras, Polyplectus, Hildaites, Mercaticeras, Hildoceras, Phymatoceras and Frechiella spp., and numerous Phylloceratids and Lytoceratids. Together with the ammonites, several gastropods were collected. They seemingly all came from the same horizons: from the lower and middle Toarcian. The specimens are fragmentary internal casts, a preservation most common in fossils from the red marl facies. Until now 34 specimens were collected. Five species were separable in this material: Eucyclus (Eucyclus) äff. capitaneus (MÜNSTER, 1844); Eucyclus (Euyclus) aff. tataensis SZABÓ, 1995; Eucyclus (Eucyclus) barnabasi SZABÓ, 1995; Eucyclus (Eucyclus) sp.; Eucyclus (Lokuticylus?) sp. and Tretospira? sp. Additionally to the specimens form the Vöröshíd quarry, sporadic examples from other Gerecse Mts localities are also discussed here. One specimen (Marmolatella? sp.) came from a new excavation near the Nagy-Pisznice quarry. This exposure was occasioned by an exceptional find of a crocodile skeleton discovered by amateur collectors some years ago. The skeletal remains came from the Toarcian limestone just above the typical Kisgerecse Marl, which is about 3 m thick in the area (KONDA 1985, CSÁSZÁR et al. 1998, fig. 8). The red limestone bed giving Marmolatella? sp. is of Variabilis Zone age (GÉCZY B. pers. com.). Two other gastropod specimens (Eeptomaria sp. and Purpuroidea? sp.) were found in the Toarcian of the Kis-Gerecse quarry, in the type section of the Kisgerecse Marl Formation. The beds, yielding the specimens (No 89. and 86., respectively), are of middle Toarcian age (Hildoceras bifrons Zone, GÉCZY, unpublished). Figure 1 Maps of the Gerecse Toarcian gastropod localities (modified after KONDA 1985 and 1986). Material and palaeoecological indications Thirty-two (from 41), more or less fragmentary, inner mould specimens were identifiable but usually with application of the open nomenclature: Eeptomaria sp. Eucyclus (Eucyclus) aff. capitaneus (MÜNSTER, 1844) Eucyclus (Eucyclus) aff. tataensis SZABÓ, 1995