Huanggexi Fm

The formation was established by the Second Regional Geological Survey of Yunnan Province in 1976. The type section is located in the Huanggexi section, Daguan County, Yunnan Province. Coordinate: 103°52′21″E, 27°50′N. The formation and the overlying Sifengya Fm were treated as the Huanggexi Member and Sifengya Member, respectively, of the Daguan Fm by Rong (1998). Since the distinctive feature of red beds is developed in the overlying strata, the authors agree with the Bureau of Geology and Mineral Resources of Yunnan Province (2008) to treat the former Huanggexi Member and Sifengya Member as the independent formations.

Synonym: (黄葛溪组）

Lower part of the formation is composed by dark gray, gray thick-bedded limestone and lenticulated limestone; Upper part is composed of gray white, light gray dolomitic quartz silt-fine sandstone intercalated with argillaceous limestone and mudstone.

The formation bears graptolites Glyptograptus, Climacograptus, Orthograptus; trilobite Meitanilaenus, Kosovopeltis, Encrinuroides；brachiopods Zygospiraella, Beitaia, Isorthis and coral Ketophyllum, which are equivalent to part of the graptolite Monograptus sedgwickii zone. The middle and upper parts yield corals Favosites, Palaeofavosites, Halysites, Heliolites, Orthophyllum, Cystiphyllum, Pycnactis, Brachyelasma etc.; brachiopod Zygospiraella, trilobite Songkania; gastropods Loxonema, Discordochilus; which are equivalent to the upper part of the graptolite M. sedgwickii zone.