Cretaceous Beds in North China

Abstract

DURING recent years the work of the Geological Survey in North China has been steadily filling the gaps in our records between the Jurassic and Pleistocene deposits, but until now no rocks of Cretaceous age have been recognised in the area. The absence of post-Jurassic marine sediments is correctly interpreted as indicating that there was no extensive submergence after that date, but it might be anticipated that the Cretaceous should be represented by locally developed continental deposits. The discoveries of Berkey, Granger, and Morris of the American Museum's third Asiatic expedition to Mongolia in 1922–3 showed that the surface of the land mass to the north underwent a periodic gentle warping throughout later Mesozoic and Tertiary times. The area of downwarp, however, was continually shifting its position, thus leading to a migration of the basins of deposition. In consequence, though no one locality yielded more than a few of the representatives of all the formations recognised, somewhere or other the party found horizons referable to practically every post-Jurassic period with the exception of the Miocene. In particular, the Iren Dabasu sandstone and shale and the other members of the Shama continental series are regarded as Cretaceous. It might, therefore, be not unreasonable to hope that deposits of similar age would be found at some point nearer the coast along the northern border of China proper, occupying the lacuna between the Jurassic eruptives and the Tertiary basalts.