Geologic units in Gibson county, Indiana

Patoka and Shelburn Formations (Pennsylvanian) at surface, covers 83 % of this area

Mostly shale and sandstone; also includes thin beds of limestone and coal. WF, top of West Franklin member

Carbondale Group (Pennsylvanian) at surface, covers 8 % of this area

Mostly shale and sandstone; also includes thin beds of limestone, clay, and coal. S, Springfield Coal Member

Bond Formation (Pennsylvanian) at surface, covers 7 % of this area

Mostly shale and sandstone; also includes thin beds of limestone and coal

Mattoon Formation (Pennsylvanian) at surface, covers 2 % of this area

Mostly shale and sandstone; also includes thin beds of coal

Bond Formation (Pennsylvanian (Kasimovian)) at surface, covers 0.2 % of this area

Bond Formation

Mattoon Formation (Pennsylvanian (Kasimovian)) at surface, covers 0.2 % of this area

Mattoon Formation.