De Graff 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 De Graff Coal Member of the Modesto Formation (Cady, in Kosanke et al., 1960, p. 37).
Named for De Graff School, Perry County.
It previously was informally called the First Cutler Rider coal.
The type section consists of exposures along Galum Creek, near De Graff School (SE cor. NE SW 21, 5S-4W).
Extent and thickness
This thin, lenticular coal occurs a few feet above the Piasa Limestone in southern Illinois.
Well log characteristics
Age and correlation
Environments of deposition
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.
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