Nonmarine Bivalve Fossils from Jurassic and Cretaceous of Chaoshui Basin, Northwest China
Chen Jinhua and Ma Shuda
pp. 76-85, 1 plate, in Chinese, with English abstract
Mesozoic bivalves have never been previously found from the Chaoshui Basin, which is located at northern Gansu Province and southern Inner Mongolia Autonomous Region of northwest China. In the present paper have been ten species referred to five genera from the Jurassic and Cretaceous of this basin describes, for the first time. The Jurassic forms are discovered from a single bed, including Pseudocardinia ? cf. busimensis (Lebedev), P. ? kweichouensis (Grabau), P. ? sibirensis Martinson, P. ? yangziensis Gu and P. ? hupehensis (Grabau). The age of the fossiliferous bed is considered as Middle–Upper Jurassic, probably Callovian–Oxfordian. The Cretaceous fossils are collected from two beds, of which the lower one contains Sphaerium pujiangense Gu et Ma and Tetoria ? sp. cf. T. ? yixianensis Gu et Wen, while the upper one yields Sphaerium selenginense (Martinson), Nakamuranaia chingshanensis (Grabau) and Unio sp. Their age probably relates to Neocomian or Valanginian–Barremian.
Keywords: nonmarine bivalves, Jurassic and Cretaceous, Chaoshui Basin