Historical:Womac 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 >>Modesto Formation >>Womac Coal Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Missourian Series
Allostratigraphy: Absaroka Sequence


M. E. Hopkins and J. A. Simon

Name Origin

The Womac Coal Member of the Modesto Formation (Kosanke et al., 1960, p. 38) is named for Womac, Maccupin County.

Type Section

The type section consists of exposures in a ravine draining into Macoupin Creek 3 miles southwest of Womac (Wanless, 1956, p. 11).

Other Names

It previously was called the Macoupin Coal (Wanless, 1931b, p. 810-811).


It is correlated with the Raben Branch Coal Member in Indiana.

Extent and Thickness

This thin coal is widely traced in the Illinois Basin along with the overlying Macoupin Limestone, from which it is separated by 1-2 feet of black fissile shale.


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., 1931b, Pennsylvanian section in western Illinois: Geological Society of America Bulletin, v. 42, p. 801-812.
WANLESS, H. R., 1956, Classification of the Pennsylvanian rocks of Illinois as of 1956: Illinois State Geological Survey Circular 217, 14 p.

ISGS Codes

Stratigraphic Code Geo Unit Designation