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National Geologic Map Database

Geologic Unit: Arnheim

Usage:

Arnheim Formation (OH,TN*)
Arnheim Shale (OH*)
Arnheim Formation of Cincinnati group [informal] (OH)

(Cincinnati group considered informal by the OH Geol. Survey. The rank or lithologic term should not be capitalized.)


Subunits:

(ascending): Sunset Member (OH), Oregonia Member (OH).


Geologic age:

Late Ordovician (late Maysvillian to Richmondian)*


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

Named from Arnheim, Brown Co., southwestern OH (US geologic names lexicons, USGS Bull. 896, 1200).


AAPG geologic province:

Cincinnati arch*


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 ([ ]).