Yuzhuang Fm

The naming section for the Jiyuan Gr, of which this is the upper formation, is located in the area from Zhangzhuang through Niezhuang to the Nanyao Reservoir, Jiyuan County, Henan. Named by the 104 Party of the Division of Exploration, Ministry of Petroleum, in 1959.

Lower part is light brownish red and purplish red sandstone, muddy sandstone and sandy mudstone. Upper part, brownish red, brownish red sandy mudstone and brownish red or yellow gray fine sandstone. The thickness is 556–600 m.

The formation contains some gastropods such as Australorbis huanghoensis. The ostracods include such species as Candoniella albicans. Fossil charophytes are relatively abundant, including Charites cf. subcylindrica, Grovesichara gonganenesis and Gyrogona qianjiangica.