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Geologic Unit: Maquoketa

Maquoketa Shale (IA*,IN,IL*,KY,MN*,MO*,WI*, and KS*-subsurface)
Maquoketa Formation (IA,MN,MO)
Maquoketa Group (IL*,IN,MO*,WI)
Maquoketa Shale Group (IL)
Maquoketa Supergroup (OH)

Ordovician, Late*

Geologic Province:
Illinois basin*
Iowa shelf*
Ozark uplift*
Upper Mississippi embayment*
Wisconsin arch*
Forest City basin*

Areal Extent:
KS* (subsurface)

Type Locality:
Exposures on Little Maquoketa River, 12 mi west of Dubuque, Dubuque Co., eastern IA (White, 1870).
Reference section: in roadcut on I-55, SE/4 sec. 19, T. 42 N., R. 6 E., Herculaneum 7.5-min quadrangle, eastern Jefferson Co., eastern MO (Thompson, 1991).

Unit Name History:
[Please note: only the White (1870), Willman and others (1975), Thompson (1991), Harrison (1997, 1999), and Nelson (1998) references include synopses here. The remaining references have yet to be added from the GNC index card files. Until then, feel free to contact us if you would like complete bibliographic citations.]
Named (White, 1870).
Revised (Calvin, 1906).
Revised in MN (Stauffer and Thiel, 1941).
Overview (Agnew and others, 1956; Weiss, 1957; Laswell, 1957).
Rank raised in IL and IN (Gutstadt, 1958).
Contacts revised (Brown and Whitlow, 1960).
Revised to Maquoketa Formation in MO (W.B. Howe and J.W. Koenig, 1961, Missouri Div. Geol. Survey and Water Res. Rpt., 2nd ser., v. 40, 185 p.).
Revised to Shale group (Buschbach, 1964).
Overview in KS (Goebel, IN Zeller, ed., 1968).
Overview in IN (R.H. Shaver and others, 1970, Indiana Geol. Survey Bull., no. 43, 229 p.).
Overview in WI (Froming, 1971).
Overview in IN (Gray, 1972).
Extended into OH; Revised to Supergroup rank (Dolly and Busch, 1972.
Overview in IL (Willman and others, 1975).
Extended into KY (Soderberg, 1981).
Contacts revised (Droste and others, 1982).
Revised (Kolata and Graese, 1983).
Overview in IA (Bunker and others, 1985).
Overview in MN (Mossler, 1987).
Revised; Age modified; Reference sections; Overview in MO (T.L. Thompson, 1991, Missouri Div. Geol. and Land Survey Rpt. Inv., no. 70, pt. 2, 282 p.).
Overview; Age modified (Frey, 1995).
Overview (Harrison, 1997).
Revised; Overview (Nelson, 1998).
Overview (Harrison, 1999).

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