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National Geologic Map Database

Geologic Unit: Pecatonica

Usage:

Pecatonica Member of Platteville Formation (IL*,IA*,MN*,WI*)
Pecatonica Member of Platteville Formation of Galena Group (IA)
Pecatonica Member of Platteville Formation of Sinnipee Group (WI)
Pecatonica Formation of Platteville Group (IL*, and MO*-local)
Pecatonica Formation of Black River Group (IN-subsurface)


Subunits:

FORMATION STATUS (alphabetical) --all in IL: Chana Member, Dane Member, Hennepin Member, Medusa Member, New Glarus Member, Oglesby Member.


Geologic age:

Late Ordovician (Mohawkian; Turinian)*


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

Type section: quarries and roadcut on East Branch of Pecatonica River just north of Woodford, in W/2 NW/4 NE/4 sec. 14, T. 2 N., R. 5 E., Lafayette Co., southwestern WI (Templeton and Willman, 1963).
Named from Pecatonica Valley, IL and WI (Hershey, 1894).


AAPG geologic province:

Illinois basin*
Ozark uplift*
Upper Mississippi embayment*
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 ([ ]).