U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
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:

Named from 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 published by U.S. Geological Survey authors.

"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 conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).