Historical:Shoal Creek Limestone Member
M. E. Hopkins and J. A. Simon
The Shoal Creek Limestone Member of the Bond Formation (Engelmann, 1868, p. 175, 177-183), the base of which is the base of the formation in all except northern Illinois, is named for Shoal Creek in Clinton County.
The type locality consists of exposures along Shoal Creek (3N-4W).
It is correlated with the La Salle Limestone of northern Illinois, the lower part of the Winterset Limestone Member of Missouri, and the Carthage Limestone Member of western Kentucky. The Shoal Creek Limestone Member is also recognized in Indiana.
Extent and Thickness
The limestone is commonly 6-8 feet thick, locally as much as 20 feet. It persists throughout most of the Illinois Basin and is quarried in southwestern Illinois.
It is generally light gray, thick bedded, and fine grained. The Shoal Creek is an easily recognized marker on geophysical logs in most of the deeper part of the Illinois Basin. It is locally cut out by the Mt. Carmel Sandstone or the McWain Sandstone.
It contains a diverse open-marine fauna.
ENGELMANN, HENRY, 1868, Geology of Clinton and Washington Counties: Geological Survey of Illinois, v. 3, p. 145-191.
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