Geologic units in Christian county, Illinois

Bond Formation (Pennsylvanian) at surface, covers 82 % of this area: Bond Formation
Lithology: limestone; shale; sandstone; clay or mud; coal; black shale
Mattoon Formation (Pennsylvanian) at surface, covers 13 % of this area: Mattoon Formation
Lithology: shale; sandstone; limestone; coal; black shale
Modesto Formation (Pennsylvanian) at surface, covers 5 % of this area: Modesto Formation
Lithology: shale; sandstone; limestone; clay or mud; coal; black shale