New progress in the study of the Lower Cretaceous of the Guyang area,Inner Mongolia

During 1∶50 000 regional survey in the Xiashihao area east of Guyang county,Inner Mongolia,the authors first collected abundant fossils of pelecypods,gastropods,ostrocods,charophytes and embryophytes in the Lower Cretaceous Guyang Formation determined previously.According to the fossils combined with the features of sediment associations,the original Guyang Formation is revised and renamed the Lower Cretaceous Lisangou Formation.