Historical:De Graff Coal Member
Lithostratigraphy: McLeansboro Group >>Modesto Formation >>De Graff Coal Member
Chronostratigraphy: Paleozoic Erathem >>Pennsylvanian Subsystem >>Desmoinesian Series
Allostratigraphy: Absaroka Sequence
M. E. Hopkins and J. A. Simon
The De Graff Coal Member of the Modesto Formation (Cady, in Kosanke et al., 1960, p. 37) is named for De Graff School, Perry County.
The type section consists of exposures along Galum Creek, near De Graff School (SE cor. NE SW 21, 5S-4W).
It previously was informally called the First Cutler Rider coal.
This thin, lenticular coal occurs a few feet above the Piasa Limestone in southern Illinois.
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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