西藏措勤地区早日垩世双壳类新材料

简述措勤地区双壳类的地层分布及组合特征，描述双壳类化石２０属２０种，其中有６新种。非海相双壳类（Ｉｓｏｄｏｍｅｌｌａ，Ｃｏｓｔｏｃｙｒｅｎａ）的发现具有重要意义。

NEW MATERIAL OF EARLY CRETACEOUS BIVALVIA FROM COQEN REGION,XIZANG(TIBET)

At present,the Bivalvia of Early Cretaceous from Coqen region,Xizang,have not been reported officially. For the first time 20 genera and 20 species of fossil Bivalvia are detailedly by described in this paper. These bivalves mainly belong to 13 families,such as Ostreidae, Trigoniidae, Fimbriidae, Vaneridae. Astartidae, Carditidae f Pteriidae, Bakevelliidae, Inoceramidae, Corbiculidae, etc., including 6 new species I namelly, Nuculana subspathulata,Ludbrookia daxungensis, Pteria coqenensis, LOP ha (s. 1.) trigona, L. (s. 1.) tenuicostata,and Isodomella rostrusa. Especially,the discovery of nonmarine Bivalvia (Isodomella,Costocyrena),has further confirmed the existence of continental interbeds in Early Cretaceous along the line from Hei He,Xainza to Bangong Co in central Xizang. This is of great significance for analysing the depositional environment at that time.