Shiyanhe Fm

The type section is at Shiyanhe in Dashiqiao Township, Xichuan County, Henan. The Shiyanhe Fm was named by Yan Guoshun, Xi Yunhong and Wang Deyou in 1983, and was published by Pei Fang et al. (1987). The Shiyanhe Fm had previously been referred to the strata consisting of mudstone, siltstone, limestone or dolomite overlying the volcanic rock of Zuoqu Fm. Pei Fang et al. (1987) divided it into Sigang Fm in the lower part and Shiyanhe Fm in the middle-upper part on the dating of the fossils. In 1991, Liu Yinhuan et al. redefined its lower and upper boundaries on the basis of corals from the mudstone or dolomitic limestone, and named the upper part without coral of the previously defined Shiyanhe Fm as the Liujiapo Fm. Considering the similar lithology of the Liujiapo Fm and the overlying Zhangwan Fm, the present book includes the Liujiapo Fm in the Zhangwan Fm.

Synonym: (石燕河组）

Lower part is composed of mudstone and dolomitic limestone. Middle part is limestone intercalated with mudstone. Upper part is mudstone intercalated with limestone. In the type area, the Shiyanhe Fm is 97.2 m thick.

Conodont fauna includes Tasmanognathus sigangensis assemblage in the lower part and Belodina stoni assemblage in the upper (Pei et al., 1987), which was merged into Yaoxianognathus yaoxianensis assemblage by Liu et al. (1991). Additionally, the associated cephalopods of Jiangxioceras-Yushanoceras assemblage and corals of Favostina-Calapocia-Plasmoporella assemblage and Agetolites-Agetolitoides- Agetolitella assemblage have been found from the Shiyanhe Fm.