Baxian Fm

The type section is located in the area of the Baxian Village to the south of the Liuma District, Zhengning County, Guizhou Province. It was named by by the Regional Geological Survey Party of Guizhou Province in 1980.

Clastics. It is divisible into two members on the basis of its lithological characteristics: Lower member is composed of grey, medium-, and thick-bedded tuffaceous basalt-bearing lithic sandstones, siltstones and claystone, intercalated with a small amount of dark-grey medium-bedded bioclastic limestone, marl, siliceous rock and basaltic conglomerate, with a thickness commonly of 150 m. Upper member consists of two parts, with its lower part being composed of brown, yellow-brown medium-bedded and thick-bedded sandstones, basaltic lithic siltstones and claystone, intercalated with a good many of sandy claystones and a small amount of thin-bedded siliceous rocks and basaltic tuffs; and its upper part being composed of grey and brown-grey medium-, and thick-bedded fine-grained sandstones, siltstones and thin-bedded siliceous rocks, with a thickness commonly of 250-400 m.

First member yields Fusulinida represented by Metadoliolina sp., Neoschwagerina sp. and Codonofusiella sp., and Conodonts such as Waagenophyllum sp. and so on.

Second member yields Fusulinida such as Codonofusiella sp. and Reichelina sp., and Ammonoids as represented by Agathiceras sp., etc.