Xilutian Fm

The naming section is the east section of the West open-cut mine, Fushun, Liaoning. Named by Hong Youchong et al. in 1980, equivalent to the Third Member of the “Guchengzi Formation” named in 1974.

A sequence consisting dominantly of green, massive mudstone with alternating brown, medium- to thick-bedded shale and light green marlstone, with distinct rhythms. The general thickness is 102–600 m.

It contains sporopollen, ostracods, gastropods, conchostraca and turtles. Sporopollen mainly includes Quercoidites, Cupuliferoidaepollenites and Tricolpites, whose characteristics are similar to those of the underlying Jijuntun Formation, and the age is mid-late Eocene. The fossil ostracods are Hemicyprinotus cf. reniformis, Cyprinotus formalis, C. novellas and Cypris subglobosa, whose age is probably Eocene–Oligocene. Fossil conchostraca includes Fushunograpta ovata and F. brachysellipsa. The fossil turtles are Anosteira manchuriana, whose age is late Eocene.