Mississippian period geologic formation in the Midwest United States
St. Louis Limestone
Stratigraphic range: Mississippian Sub-period
Rock anhydrite (St. Louis Limestone; subsurface gypsum mine in Martin County, Indiana)
Type
Geological formation
Unit of
Blue River Group
Sub-units
Dover Chert, Horse Cave Member, Sisson Member
Underlies
Ste. Genevieve Limestone
Overlies
Salem Formation[1]
Thickness
up to 100 feet (30 m)[2]
Lithology
Primary
Limestone
Other
Shale, chert[2]
Location
Region
Illinois, Indiana, Tennessee, Kentucky and Missouri
Country
United States
Type section
Named for
St. Louis, Missouri[1]
Named by
Englemann
Year defined
1847
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 bryozoanFenestrellina.
^ abThompson, Thomas L., 2001, Lexicon of Stratigraphic Nomenclature in Missouri, Missouri Department of Natural Resources, Division of Geology and Land Survey, Report of Investigation Number 73, p. 252
^ abHowe, W. B. and J. W. Koenig, The Stratigraphic Section in Missouri, Missouri Geological Survey, 1961, p. 69