USGS Visual Identifier
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Geologic Unit: Chatham

Chatham Group of Newark Supergroup (NC*,SC*)

Triassic, Late*
Carnian, early*
Carnian, middle*
Carnian, late*
Norian, early*

Geologic Province:
Piedmont-Blue Ridge province*
Crowburg basin*
Wadesboro basin*
Ellerbe basin*
Sanford basin*
Deep River basin*
Areal Extent:

Type Locality:
Not designated. Named from Chatham Co., NC (Emmons, 1857).

Pekin Formation (NC*), Cumnock Formation (NC*), Sanford Formation (NC*)

Unit Name History:
Named Chatham series (Emmons, 1857).
Age modified; Biostratigraphic dating (Cornet, 1977).
Revised to Chatham Group (Olsen and others, 1982).
Revised; Extended into SC (Brown, 1985).
Age modified; Biostratigraphic dating (Litwin and Ash, 1993).
Biostratigraphic dating (Huber and others, 1993).
[When referring to the Chatham series of Emmons (1857), please use informally. The practice of employing "series" for lithostratigraphic or lithodemic nomenclature is now regarded as improper (see ACSN, 1961, 1970; NACSN, 1983). The term "Series" is applied formally only to chronostratigraphic units.]

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