Usage:
Arnheim Formation (OH*, and TN*-local)
Arnheim Shale (OH*)
Arnheim Formation of Cincinnati group (informal) (OH)
(informal Cincinnati group is the usage of the OH Geol. Survey. The rank or lithologic term should not be capitalized.)
Subunits:
(ascending) --all in OH: Sunset Member, Oregonia Member.
Geologic age:
Late Ordovician (Cincinnatian; 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 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 ([ ]).