Historical:Calhoun Coal Member
M. E. Hopkins and J. A. Simon
The Calhoun Coal Member of the Mattoon Formation (Noé, 1934, p. 103) is named for Calhoun, Richland County.
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.
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.
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