Echa Fm

The type section is located in the Eding area about 40 km to the south of Dongfang City Town, Hainan Province. It was named by the Regional Geological Survey Party of Guangdong Province in 1964, and was officially cited by Sheng Jinzhang (1965).

Mixed marine facies. The major rock types are purple-grey, grey-brown and grey-black slate, silty plate, carbonaceous slate, sericite fine-grained quartz-sandstone, intercalated with thin-bedded black silicified bioclastic micrite, recrystallized micritic lenses. In the Qingtianxia section the formation is in a fault contact with the underlying Qingtianxia Fm (late Carboniferous), with its upper part being short of its top due to the faulting, with an exposed thickness of 498 m; while in the section on the western slope of the Eding Hill the exposed thickness of the formation is of about 90 m, being in a conformable contact with the overlying Eding Fm.

Its lower part yields Conodonts such as Sweetognathus whitei, S. behnkeni, Rabeignathus asymmetricus and Anchignathodus typicalis, etc.; while the limestone lenses of its upper part yield Fusulinida represented by Parafusulina sp., as well as brachiopods and bryozoan fossils.

It is interpreted as a littoral shallow-sea shelf-facies of carbonate and terrigenous clastics.