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National Geologic Map Database

Geologic Unit: Richmond

Usage:

No current usage.
(†Richmond Group has been abandoned as a lithostratigraphic term, and has been used as a chronostratigraphic term (Richmondian Stage) for some time. To prevent confusion, the use of Richmond as a lithostratigraphic term should be avoided.)


Geologic age:

Ordovician, Late
Cincinnatian


Type section, locality, area and/or origin of name:

Richmond, IN (Winchell and Ulrich, 1897).


AAPG geologic province:

Cincinnati arch
Illinois basin
Ozark uplift
Michigan basin


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

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

Slash (/) indicates name does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).