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Geologic Unit: Cowen
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Map showing publication footprint
  • Usage in publication:
    • Cowen Member
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Dolomite
  • AAPG geologic province:
    • Wisconsin arch
Publication:

Willman, H.B., and Kolata, D.R., 1978, The Platteville and Galena Groups in northern Illinois: Illinois Geological Survey Circular, no. 502, __ p.


Summary:

Pg. 30. Cowen Member of Grand Detour Formation. Consists mostly of thin- to medium-bedded dolomite to shaly dolomite. Thickness 2.3 m at type section; ranges from 1.8 to 5.4 m. Overlies Mifflin Formation; underlies Stillman Member of Grand Detour Formation. Age is Middle Ordovician.
Type section: Brookville Northwest Section, in quarry of north side of ravine northeast of U.S. Highway 52, in NE/4 SE/4 NW/4 sec. 21, T. 24 N., R. 7 E., Carroll Co., IL, 1.6 km northwest of Brookville, Ogle Co., north-central IL. Named from Cowen School, 3.2 km southwest of type section.

Source: US geologic names lexicon (USGS Bull. 1564, p. 41).


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 ([ ]).

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