Pg. 37, 88, 49 (table 1), pl. 1. Chapel coal member of Modesto formation (new) of McLeansboro Group. Replaces name Trivoli (No. 8) coal so that name Trivoli can be retained for the sandstone. In southeastern area, occurs above Trivoli sandstone member and below New Haven coal member; in southwestern area, above the Trivoli and below Carlinville limestone member; in western and northern area, above the Trivoli and below Cramer limestone member (new). Age is Pennsylvanian. Report presents new rock-stratigraphic classification of Pennsylvanian strata in Illinois. Cyclical classification retained but is entirely independent of rock-stratigraphic classification.
Type locality: in SW/4 sec. 3, T. 8 N., R. 5 E., Glasford quadrangle, Peoria Co., north-central IL. Named from Graham Chapel, about 2 mi north of type locality.

Source: Publication; US geologic names lexicon (USGS Bull. 1200, p. 720).