Cedar Bluff Limestone Group

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Lithostratigraphy: Pope Megagroup >>Cedar Bluff Limestone Group
Chronostratigraphy: Paleozoic Erathem >>Mississippian Subsystem >>Valmeyeran Series >>Genevievian Stage
Allostratigraphy: Kaskaskia Sequence

Primary source

Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.

Contributing author(s)

Elwood Atherton, Charles Collinson, and Jerry A. Lineback


Original description

Cedar Bluff Limestone Group (Swann, 1963, p. 63).


Named for the quarry of the Cedar Bluff Limestone Company, formerly the Ohara quarry, southeast of Princeton, Caldwell County, Kentucky (S1/2 21-H-20).

Other names


It was originally called the Ohara Limestone, but the name Ohara is widely used for the Karnak Member of the Ste. Genevieve in the subsurface.

Type section

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Reference section

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Stratigraphic relationships

The Valmeyeran-Chesterian contact falls within the Cedar Bluff Group at the top of the Levias Limestone Member of the Renault Formation.

Extent and thickness

It occurs in southeastern Illinois and is exposed in Hardin County.


The Cedar Bluff Limestone Group consists of the Downeys Bluff, Yankeetown, and Renault Formations in areas where these formations are dominantly limestone (fig. M-25).




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Age and correlation

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Economic importance



SWANN, D. H., 1963, Classification of Genevievian and Chesterian (Late Mississippian) rocks of Illinois: Illinois State Geological Survey Report of Investigations 216, 91 p.

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