Historical:Calhoun Coal Member

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Handbook of Illinois Stratigraphy
Series Bulletin 95
Author H. B. Willman, Elwood Atherton, T. C. Buschbach, Charles Collinson, John C. Frye, M. E. Hopkins, Jerry A. Lineback, Jack A. Simon
Date 1975
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Lithostratigraphy: McLeansboro Group >>Mattoon Formation >>Calhoun Coal Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Missourian Series
Allostratigraphy: Absaroka Sequence


M. E. Hopkins and J. A. Simon

Name Origin

The Calhoun Coal Member of the Mattoon Formation (Noé, 1934, p. 103) is named for Calhoun, Richland County.

Type Section

The type section is in a roadcut about 2 miles southeast of Calhoun (NE NE NE 6, 2N-14W) (Kosanke et al., 1960, p. 40,82).

Extent and Thickness

The Calhoun Coal is widespread in eastern Illinois, where it is 2 feet thick or less and is overlain by the Bonpas Limestone. The Calhoun is also present on the western side of the deeper part of the Illinois Basin, where it occurs a foot or two below the Omega Limestone.

Stratigraphic Position

The Calhoun lies about 525 feet above the Shoal Creek Limestone.


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.
NOÉ, A. C., 1934, Our present knowledge of American coal ball plants: Illinois Academy of Science Transactions, v. 26, no. 3, p. 103.

ISGS Codes

Stratigraphic Code Geo Unit Designation