Bivalve and gastropod fauna from the Liassic Ammonitico Rosso facies in the Bilecik Area (Western Pontides, Turkey)

Fossil bivalves and gastropods originating from clay marly Ammonitico Rosso facies are described from the Western Pontides (Turkey). The fauna of Early Jurassic (Late Sinemurian-Early Pliensbachian) age is composed of 20 species of bivalves and 41 species of gastropods. The following new species are described: Parainoceramus altineri, Parainoceramus bileciki, Parainoceramus farinacciae , Parainoceramus nicosiai, Scissurella? (Scissurella?) szaboi, Margarites (Margarites?) kocyigiti, Brookula? (Brookula?) oliverioi. The fauna is indicative of a firm bottom with scattered hard-grounds at a relative shallow depth. The condensation phoenomena were caused by several removals of debris that could happen from time to time but not continuously. The assemblage seems to be controlled by the type of environment rather than by paleobiogeograpbic distribution.