Shuanmazhuang Fm

The type section is located at Shuanmazhuang, about 5 km north of Shetai Town, Urad Front Banner, Inner Mongolia. It was named by Sun Jianchu in 1934.

Sandstone, Coal and Claystone. A complete rhythmic layer formed by conglomerate-sandstone-siltstone and shale ascending. The lower and middle parts have intercalations of multiple coal seams. In the type section, the bottom part is composed of gray-white fine-grained conglomerate and pebbly sandstone intercalated with shale and multi-layered coal; the middle part is of gray-white pebbly quartz sandstone intercalated with shale, siltstone, sandstone, fine-grained conglomerate and coal seams; the upper part is dominated by black-green silty shale, intercalated with light-gray pebbly sandstone, fine-grained conglomerate, etc.; the top is of white pebbly quartzite intercalated with yellow-green thin-bedded silty shale. Thickness 732 m.

Contains abundant fossil Plants, i.e. the Neuropteris pseudovata-Lepidodendron posthumii assemblage, including: Neuropteris plicata, Lepidodendron ninghsiaense, L. tachingshanense, L. oculus felis, Calamites suckowii, C. cistii, Tingia carbonica, Asterophyllites longifolius, etc. (Huang Benhong, 1987).

It is interpreted as a coal cyclothems.