Geologic units in McLean county, Illinois

Bond Formation (Pennsylvanian (Kasimovian)) at surface, covers 45 % of this area

Bond Formation

Shelburn-Patoka Formations undivided (Pennsylvanian (Kasimovian)) at surface, covers 44 % of this area

Shelburn-Patoka Formations undivided.

Mattoon Formation (Pennsylvanian (Kasimovian)) at surface, covers 9 % of this area

Mattoon Formation.

Carbondale Formation (Pennsylvanian (Moscovian to Kasimovian)) at surface, covers 0.6 % of this area

Carbondale Formation.

Tradewater Formation (Pennsylvanian (Bashkirian to Moscovian)) at surface, covers 0.3 % of this area

Tradewater Formation