Geologic units in Jefferson county, Illinois

Mattoon Formation (Pennsylvanian (Kasimovian)) at surface, covers 67 % of this area

Mattoon Formation.

Bond Formation (Pennsylvanian (Kasimovian)) at surface, covers 32 % of this area

Bond Formation

Shelburn-Patoka Formations undivided (Pennsylvanian (Kasimovian)) at surface, covers 0.5 % of this area

Shelburn-Patoka Formations undivided.