USGS Visual Identifier
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Geologic Unit: Knox

Knox Dolomite (AL*,IN,KY*,MS,OH*,TN*)
Knox Group (AL,GA*,IL*,KY*,TN*,VA*,WV)
Knox Supergroup (IN,KY,OH)
/Knox megagroup [informal] (IL,KY)
["Megagroup" not recognized as a formal stratigraphic rank term (CSN, 1961; NACSN, 1983). Considered informal. The rank or lithologic term should not be capitalized.]

Cambrian, Late*
Ordovician, Early*
Ordovician, Middle(?)

Geologic Province:
Appalachian basin*
Illinois basin*
Black Warrior basin

Areal Extent:

Type Locality:
Type area: Knox Co., TN (Safford, 1869).

GROUP STATUS: Copper Ridge Dolomite, Chepultepec Dolomite, Longview Dolomite, Kingsport Limestone, Mascot Dolomite (TN,VA*); Copper Ridge Dolomite, Chepultepec Dolomite, Longview Dolomite, Newala Dolomite (AL,GA,KY*); Copper Ridge Dolomite, Chepultepec Dolomite, Kingsport Limestone, Mascot Dolomite (TN*); Odenville Limestone (AL); Rose Run Sandstone (KY*).

Unit Name History:
Named Safford (1869).
Areal limits (Smith, 1907; Bassler, 1909).
Revised (Rodgers and Kent, 1948).
Areal limits (Freeman, 1949).
Overview (Rodgers, 1953).
Revised (Miller and Fuller, 1954).
Areal limits (Gutstadt, 1958).
Areal limits; Revised to /Knox Megagroup (Swann and Willman, 1961).
Overview (Englund and others, 1961).
Areal limits; Revised (Calvert, 1962).
Areal limits (Cardwell and others, 1968).
Revised (Harris, 1969).
Areal limits (Thomas, 1972).
Overview (Soderberg and Keller, 1981; Cable and Beardsley, 1984; Droste and Patton, 1985).
Revised (Osborne, 1990).
Overview (Henderson, 1991).
Revised (Osborne and Raymond, 1992).
Revised; Age modified (Osborne, 1992).
Overview (Moore and others, 1993).
Revised; Areal limits (Nelson and others, 1996).
Revised (Ryder and others, 1996).
Areal limits; Revised (Nelson, 1996).
Revised (Ryder and others, 1997).
Areal limits (Nelson, 1998).

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