Yankou Fm
Type Locality and Naming
The type section is at Yankou 15 km south of Yuqian Town in Lin'an County, western Zhejiang. The Yankou Fm was named by Zhejiang Compiling Group for Regional Stratigraphic Scale in 1979.
Synonym: (堰口组）
Lithology and Thickness
The formation is composed of greenish gray to dark gray or black mudstone, with sandstone intercalations in the upper part. In the type area, the Yankou Fm is 76 m thick.
Relationships and Distribution
Upper contact
It is conformably overlain by the sandy mudstone and siltstone of the Anji Fm
Regional extent
It can extend northward to Deqing and eastward to Tonglu, and has a similar mixed fauna to that in the type area.
GeoJSON
Fossils
This stratigraphic unit yields graptolites Normalograptus extraordinarius, N. bohemicus; brachiopod Paromalomena cf. polonica; trilobite Allodesma sp.; bivalve Plectambonitids of Late Ashgill N. bohemicus-N. extraordinarius assemblage.
Age
Depositional setting
Additional Information