Geologic units in Macon county, Illinois

Bond Formation (Pennsylvanian (Kasimovian)) at surface, covers 55 % of this area

Bond Formation

Mattoon Formation (Pennsylvanian (Kasimovian)) at surface, covers 29 % of this area

Mattoon Formation.

Shelburn-Patoka Formations undivided (Pennsylvanian (Kasimovian)) at surface, covers 16 % of this area

Shelburn-Patoka Formations undivided.