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National Geologic Map Database

Geologic Unit: Cedar Valley

Usage:

Cedar Valley Limestone (IL*,IA*,MO)
Cedar Valley Formation (IL,IA,MN,MO)
Cedar Valley Group (IL,IA,MN,MO)


Subunits:

GROUP STATUS (alphabetical): Coralville Formation (IL,IA,MN,MO), Lithograph City Formation (IL,IA,MN,MO), Little Cedar Formation (IL,IA,MO), Shell Rock Formation (IA).
FORMATION STATUS (alphabetical): Ashland limestone facies (informal) (MO), Callaway facies (informal) (MO), Coralville Limestone Member (IA), Coralville Member (IL), Hoing Sandstone Member (IL), Linwood Member (IL), Littleton Member (IA), Rapid Limestone Member (IA), Rapid Member (IL), Solon Limestone Member (IA), Solon Member (IL), State Quarry Limestone Member (IA).


Geologic age:

late Middle Devonian to early Late Devonian (Givetian to Frasnian)*


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

Exposures in valley of Cedar River, eastern IA (McGee, 1891).


AAPG geologic province:

Illinois basin*
Iowa shelf*
Lincoln anticline
Ozark 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 ([ ]).