In the present paper a brief account is given of the depositional characteristics,the classification, the deuterodiagenetic changes and the reservior behavior of the carbonate rocks in the Sinian Dengying Formation in Southwest China. The authors have come to the conclusions: (1) During the Dengying age, this region was, as a whole, covered by a vast expanse of epicontinental sea; while in central Sichuan and northern Guizhou spread a great mass of shallow-water carbonate platform, and in western Hunan and Hubeiwas a still water basin. (2) In the Dengying Formation, dolomites are of eonnate deposits. The thallophyta seem apparently to have plaid an important role in the rock-forming and in the reef-building. (3) Thin-bedded algal dolomites with botryoidal structure were deposited on the Siehuan-Guizhou carbonate platform. As characterized by the presence of bedded reef or hicstrome, this type of dolomites is more or less of interest to the study of stratigraphy.
