USGS Visual Identifier
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Geologic Unit: Bigby

Bigby Limestone of Nashville Group (TN*)
[Also called /Bigby-Cannon Limestone of Nashville Group. The use of a hyphen between undifferentiated formations has not been considered proper notation since 1933 (see CSN, Art. 13a, p. 437-438). Where the formations have not been separated in the field, it is considered proper notation to add the word "and", "undifferentiated", "included", etc.; and list formations in order of age (youngest first).]

Ordovician, Middle*
Geologic Province:
Cincinnati arch*

Areal Extent:

Type Locality:
Exposures on Big Bigby Creek, Maury Co., TN (Hayes and Ulrich, 1903).

Unit Name History:
Named Bigby Limestone (Hayes and Ulrich, 1903).
Contacts revised (Ulrich, 1924).
Revised to /Bigby-Cannon Limestone; assigned to Nashville Group (Wilson, 1949).
Overview (Harris and Milici, 1977; Clark and others, 1993).
Age modified (Frey, 1995).

Note: If you need more information, please contact Nancy Stamm (
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses ().

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Database project personnel
Last modified: 15-Jan-2013