St. Louis Limestone

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St. Louis Limestone
Stratigraphic range: Mississippian Sub-period
TypeGeological formation
Unit ofBlue River Group
UnderliesSte. Genevieve Limestone
OverliesSalem Formation[1]
Thicknessup to 100 feet (30 m)[2]
OtherShale, chert[2]
RegionIllinois, Indiana, and Missouri
CountryUnited States
Type section
Named forSt. Louis, Missouri[1]
Named byEnglemann
Year defined1847

The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri. It consists of sedimentary limestone with scattered chert beds, including the heavily chertified Lost River Chert Bed in the Horse Cave Member. It is exposed at the surface through western Kentucky and Middle Tennessee, including the city of Clarksville, Tennessee. The limestone deposit is Mississippian in age, in the Meramecian series, roughly 330-340 million years old.

Fossils commonly found in the St. Louis include the rugosan corals Lithostrotion and Lithostrotionella and the bryozoan Fenestrellina.

See also[edit]