Sorento Limestone Member
Willman, H. B., Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, and Jack A. Simon, 1975, Handbook of Illinois Stratigraphy: Illinois State Geological Survey Bulletin 95, 261 p.
M. E. Hopkins and J. A. Simon
The Sorento Limestone Member of the Bond Formation (Simon, in Wanless, 1955, p. 1764).
Named for Sorento, Bond County.
The type section consists of outcrops along the south-flowing tributary of Dry Fork just southwest of Sorento (NE NE 6, 6N-4W) (Kosanke et al., 1960, p. 39).
In southwestern Illinois the Sorento generally lies 15-20 feet above the Shoal Creek Limestone. In the deeper part of the Illinois Basin the interval is usually 20-40 feet, but locally it may be as much as 100 feet.
Extent and thickness
The Sorento Limestone and the underlying unnamed coal have been recognized throughout much of the Illinois Basin. The Sorento is less than 2 feet thick.
The limestone is generally fine grained and medium gray.
Well log characteristics
It contains an open-marine fauna composed primarily of brachiopods, crinoids, and gastropods.
Age and correlation
The Sorento is tentatively correlated with the Little Vermilion Limestone of northern Illinois.
Environments of deposition
KOSANKE, R. M., J. A. SIMON, H. R. WANLESS, and H. B. WILLMAN, 1960, Classification of the Pennsylvanian strata of Illinois: Illinois State Geological Survey Report of Investigations 214, 84 p.
WANLESS, H. R., 1955, Pennsylvanian rocks of Eastern Interior Basin: American Association of Petroleum Geologists Bulletin, v. 39, p. 1753-1820 (see 1962).
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