Heizhanggou Fm

The naming section is located at Heizhanggou, Fangxian County, Hubei Province. Named by Lei Yizhen, Zhang Qingru and Sun Quanying in 1979.

Hubei - NW. Lower part is alternating beds of thick- and moderately thick-bedded, grayish brown conglomerate and sandy conglomerate and light brown calcareous sandstone and sandy mudstone with calcareous concretions and grayish green worm-like bands, locally intercalated with cream-colored, light red and grayish white limestone. Upper part is light red, brownish red and yellowish brown mudstone and marlstone, with grayish white loose sandstone or fine sandstone. The thickness is ~765 m.

Amynodontids, Brontotheriids and Yuomys sp. were collected from the lower part of the formation at Leijiawan; Breviodon minutus was found in the upper part of the formation at Heizhanggou; and Hapalodectes sp. and Breviodon sp. were taken from Jinjiawan in the eastern part of the Fangxian basin. A number of species of the above-mentioned fossil mammals usually appear in the Yi’erdingmanha fauna of China; so the age of this formation should be Middle Eocene.