Usage:
Lone Rock Formation of Tunnel City Group (IA,MN,WI)
Lone Rock Member of Tunnel City Formation (WI-recognized locally in Sauk Co.)
Subunits:
(alphabetical) --all in IA,MN,WI: Birkmose Member, Reno Member, Tomah Member.
Geologic age:
Late Cambrian
Type section, locality, area and/or origin of name:
Named from exposures in roadcut on Highway 137 south of village of Lone Rock, and in south bluff of Wisconsin River in Iowa Co., central WI (Ostrom, 1966).
AAPG geologic province:
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 ([ ]).