Pg. 37, 48 (table 1), pl. 1. DeGraff coal member of Modesto formation (new) of McLeansboro group. Name applied to coal member in lower part of formation. Stratigraphically above Piasa limestone member and below Pond Creek coal member (new). Has been referred to as "1st Cutler Rider coal." Name credited to Cady (unpub. manuscript). Piasa limestone and DeGraff, Pond Creek, and Lake coals may be included in the complex West Franklin member in eastern part of area. Age is Pennsylvanian. Presentation of new rock-stratigraphic classification of Pennsylvanian of Illinois. Cyclical classification is retained but is entirely independent of rock-stratigraphic classification.
Type locality: in southeast corner NE/4 SW/4 sec. 21, T. 5 S., R. 4 E., Perry Co., southeastern IL. Named from DeGraff School about 1 mi northeast of exposure.
[Name spelled De Graff in GNU records (USGS DDS-6).]

Source: US geologic names lexicon (USGS Bull. 1200, p. 1074-1075).