Usage:
Trempealeau Formation (IL*,IN*,IA*,MI*,OH*,WI*)
Trempealeau Formation of Lake Superior Group (MI)
Trempealeau Group (IA,WI)
Geologic age:
Ordovician, Early (IA)
Cambrian, Late*
Type section, locality, area and/or origin of name:
Well displayed, and in fairly typical composition, in Trempealeau Bluff on Mississippi River [at Trempealeau, Trempealeau Co., WI] (Ulrich, 1924, Wisconsin Acad. Sci., Arts, Letters Trans., v. 21, p. 72-90; US geologic names lexicons, USGS Bull. 896, 1200).
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 ([ ]).