Chutanlong Fm

The type section is located in Erdubaoyuan River, Zixing City, Hunan Province, which was named by Erzhen Liu and Zaishu Yuan in 1951.

Synonym: The coal-bearing strata in Sandu coral mine in Zixing City, Hunan Province was named as “Luoxianling coal” by XiChu Tan in 1933, which was divided into “Yangmeilong Bed” and “Tanglong Bed”. But it was redivided by Yuanzhen Liu and Zaishu Yuan in 1951, including Chutanlong bed, Yangmeilong Bed, Tanglong Bed, Maoxianling Sandstone and Shigu Bed, in ascending order, the former two were interpreted of Late Triassic and the later three were Jurassic. The proposed names were followed by regional geology of Hunan Province (1988), but the definition was revised. The Chutanlong Bed represented the lower part of original “Chutanlong Bed” and the Chutanlong Bed was changed to Chutanlong formation. Additionally, the Yangmeilong, Tanglong and Chutanlong formations were suggestive of Late Triassic.

This formation is represented by greyish silty mudstone and quartz sandstone. Bottom of Chutanlong formation is grey siltstone and sandstone with conglomerate and iron nodules.

Bivalves: Umonites cf. dubia, Guangdongella luopaduensis, Myophoriopis sp.; Plants: Anthrophyopsis crassinerois, Pterophyllum bavien, Nilssonia acuminala, Otozamites