Dongjun Fm

The naming section is located in the vicinity of Pingguo and Nazhou, Baibi Village, Silin Township, Tiandong County, Guangxi. Named by the Guangxi Regional Geological Survey Party in 1975.

This formation refers to the limestone member assigned by the Guangxi Petroleum Party to the lower part of the Nadu Formation. According to the section described by Ding Suyin et al. (1977), Lower part is grayish white and grayish black limestone, marlstone and conglomeratic limestone with concentric or oolitic structure. Upper part is grayish yellow, grayish white and yellowish brown calcareous mudstone and grayish red and grayish black marlstone, with calcareous concretions intercalated in mudstone; It is generally ~30 m thick, but up to 120 m at the Pingguo-Nazhou section.

According to Ding Suying et al. (1977), in addition to fishes (Mylopharyngodon sp.) and reptiles (cf. Lianghusuchus sp. etc.), the vertebrate fossils discovered in the formation also have at least 14 mammalian species belonging to 11 genera, of which the 6 genera Andrewsarchus, Teleolophus, Protitan, Forstercooperia, Eudinoceras and Metatelmatherium are shared with the Irdin Manha fauna of Inner Mongolia. Although another 6 genera (Diplolophodon, Amynodon, Eusmilus, Prohyracodon, Hianodon and Probrachyodus) have not been found in the Irdin Manha fauna, they may correlate with related genera in corresponding horizons (e.g. the upper part of the Lushi formation in Henan and the lower part of the Lumeiyi Formation in Yunnan) in other areas.

It is shallow lacustrine deposits.