Some new fossil materials and new understanding of the Daxiong Group in Tibet

The bivalves Ludbrookia daxungensis,L.daxungensis,Rasatrix cf.suzulii and Arctica subexten-sa and the gastropod Biplica obliqu discovered in the Dawaxung Group have the features of the Creta-ceous fauna,which suggests that the Dawax ung Group was deposited in the Early Cretaceous Hauterivian-Albrian rather than in the Mid-Upper Jurassic and corresponds completely with the upper part of the Ze-long Group in the area.