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