U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database

Geologic Unit: Eau Claire

Usage:

Eau Claire Formation (IL*,IN*,KY*,MN*,MO)
Eau Claire Formation of Elk Mound Group (WI)
Eau Claire Formation of Knox Group (IL-notably in southern part)
Eau Claire Formation of Munising Group of Potsdam Supergroup (IN-subsurface)
Eau Claire Formation of Munising Group (MI-subsurface)
Eau Claire Sandstone (IL*,IN*,IA*,MI*,MN*,OH*)
Eau Claire Sandstone of Dresbach Group (IA*,MI*,MN*,OH*,WI*)
Eau Claire Sandstone of Elk Mound Group (WI)


Geologic age:

Middle to Late Cambrian (Croixan; Lincolnian to Millardan; Marjuman to Steptoean)*


Type section, locality, area and/or origin of name:

Named from exposures at mouth of Eau Claire River, near City of Eau Claire, Eau Claire Co., western WI (US geologic names lexicons, USGS Bull. 896, 1200).


AAPG geologic province:

Cincinnati arch*
Illinois basin*
Iowa shelf*
Lincoln anticline
Michigan basin*
Sioux uplift*
Wisconsin arch*


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).