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Geologic Unit: Platteville

Platteville Dolomite (WI)
Platteville Limestone (IA*,MN*,WI*)
Platteville Formation (IA*,IL*,MN*,WI*)
Platteville Formation of Simpson Group (KS*-subsurface of North Kansas basin)
Platteville Formation of Sinnipee Group (WI)
Platteville Group (IA,IL*,MO,WI)
Platteville Group of /Ottawa megagroup [informal] (IL)
["Megagroup" not recognized as a formal stratigraphic rank term (CSN, 1961; NACSN, 1983). Considered informal. The rank or lithologic term should not be capitalized.]

Ordovician, Middle*

Geologic Province:
Wisconsin arch
Williston basin
Iowa shelf*
Sioux uplift*
Forest City basin*
Illinois basin*
Areal Extent:
KS* (subsurface)

Type Locality:
Typical exposures in vicinity of Platteville, Grant Co., WI (Bain, 1905).
Reference section: roadcut U.S. Highway 151, in NW/4 NE/4 sec. 12, T. 2 N., R. 2 W., Grant Co. (Agnew and others, 1956).

Hidden Falls Member (MN,WI).

Unit Name History:
First used (Bain, 1905).
Hidden Falls Member named (Sloan, 1956).
Areal limits (Stevenson, 1962).
Overview in KS (Goebel, IN Zeller, ed., 1968).
Usage in IL (Willman and Kolata, 1978).
Usage in WI (Koehler, 1987).
Isotopic dating (Marvin and Mehnert, 1988).
Correlation information (Frey, 1995).

Note: If you need more information, please contact Nancy Stamm (
Asterisks (*) indicate usage by the U.S. Geological Survey. Other usages by state geological surveys.

"No current usage" implies that a name has been abandoned or that it has fallen into disuse. Former usage and, if known, replacement name given in parentheses ().

Slashes (/) indicate unit name usage violates the 1983 North American Stratigraphic Code. This violation may be explained within brackets ([ ]).

U.S. Department of the Interior, U.S. Geological Survey, Reston, VA, USA
Database project personnel
Last modified: 15-Jan-2013