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National Geologic Map Database

Geologic Unit: Joliet

Usage:

Joliet Dolomite (IL)
Joliet Formation (IL)
Joliet Limestone (IL*)


Subunits:

Brandon Bridge Member, Markgraf Member, Romeo Member


Geologic age:

Silurian (Llandovery to Ludlow; Niagaran Provincial Age)*


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

Type section: National Stone Company quarry, includes all strata above weathered and pitted surface occurring 1 to 3 ft above STRICKLANDIA PYRIFORMIS zone up to near top of quarry, Joliet, Will Co., northeastern IL (Savage, 1926).


AAPG geologic province:

Illinois basin*


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 ([ ]).