Usage:
No current usage.
(†McMillan Formation (OH*) considered obsolete. Is same as Grant Lake Formation. See Grant Lake.)
Geologic age:
Late Ordovician (Cincinnatian; Maysvillian)
Type section, locality, area and/or origin of name:
Cincinnati, OH. Named from McMillan Street (Bassler, 1906).
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 ([ ]).