U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database

Geologic Unit: Barnhart

Usage:

No current usage.
(†Barnhart Formation (MO) is same as Spechts Ferry Formation of Decorah Group. See Spechts Ferry.)


Geologic age:

Late Ordovician (Mohawkian)


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

Type section: Koch Valley School on U.S. Highway 61-67, 2 mi south of Barnhart, Kimmswick 15-min quadrangle, Jefferson Co., east-central MO (Cooper, 1956).


AAPG geologic province:

Illinois 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 ([ ]).