Usage:
Mifflin Formation of Platteville Group (IL)
Mifflin Member of Platteville Formation of Sinnipee Group (WI)
Mifflin Bed of McGregor Member of Platteville Formation (MN)
Subunits:
FORMATION STATUS (alphabetical) --all in IL: Blomeyer Member, Brickeys Member, Briton Member, Establishment Member, Hazelwood Member.
Geologic age:
Late Ordovician (Mohawkian; Turinian)
Type section, locality, area and/or origin of name:
Named from exposures in roadcuts and stream banks of Pecatonica River at Mifflin, in NE/4 sec. 34, T. 5 N., R. 1 E., Iowa Co., southwestern WI (Bays [abs.], 1938).
AAPG geologic province:
Sioux uplift
Wisconsin 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 ([ ]).