Calhoun Coal Member

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Lithostratigraphy: McLeansboro Group >>Mattoon Formation >>Calhoun Coal Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Missourian Series
Allostratigraphy: Absaroka Sequence

Primary source

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.

Contributing author(s)

M. E. Hopkins and J. A. Simon


Original description

The Calhoun Coal Member of the Mattoon Formation (Noé, 1934, p. 103).


Named for Calhoun, Richland County.

Other names


Type section

Type location

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).

Type author(s)

Type status

Reference section

Reference location

Reference author(s)

Reference status

Stratigraphic relationships

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

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.





Well log characteristics


Age and correlation

Environments of deposition

Economic importance



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