Cohn Coal 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 Cohn Coal Member of the Mattoon Formation (Newton and Weller, 1937, p. 18).
Named for Cohn (now called Livingston), Clark County.
The type section consists of an exposure on the south side of Big Creek, about 2.5 miles from Livingston (NE 1, 11N-12W).
At the type locality, it lies 22 feet above the Livingston Limestone and 12 feet below the base of the Merom Sandstone. A 16-inch thick nodular limestone containing numerous Spiroibis occurs 2 feet above the coal.
Extent and thickness
The Cohn Coal occurs in eastern Illinois, where it is generally less than 10 inches thick. At its type locality it is only 2 inches thick.
Well log characteristics
Age and correlation
To the south in Crawford County, the Cohn Coal is correlated with a thin coal that has been mined in the vicinity of Flat Rock. In that area the Cohn Coal lies at or very near the base of the Merom Sandstone, which may have eroded the coal in some areas.
Environments of deposition
NEWTON, W. A., and J. M. WELLER, 1937, Stratigraphic studies of Pennsylvanian outcrops in part of southeastern Illinois: Illinois State Geological Survey Report of Investigations 45, 31 p.
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