Geologic units in Hardin county, Illinois

Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone) (Mississippian (Visean)) at surface, covers 27 % of this area

Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone).

St. Louis Limestone (Mississippian (Visean)) at surface, covers 17 % of this area

St. Louis Limestone.

Caseyville Formation (Pennsylvanian (Bashkirian)) at surface, covers 16 % of this area

Caseyville Formation

Upper Pope Group (Tar Springs Sandstone through Kinkaid Limestone) (Mississippian (Serpukhovian)) at surface, covers 16 % of this area

Upper Pope Group (Tar Springs Sandstone through Kinkaid Limestone).

Ste. Genevieve Limestone (Mississippian (Visean)) at surface, covers 9 % of this area

Ste. Genevieve Limestone.

Ullin and Salem Limestones (Mississippian (Visean)) at surface, covers 6 % of this area

Ullin and Salem Limestones in southern Illinois.

Tradewater Formation (Pennsylvanian (Bashkirian to Moscovian)) at surface, covers 5 % of this area

Tradewater Formation

Ft. Payne Formation (Mississippian (Tourniaisian to Visean)) at surface, covers 3 % of this area

Ft. Payne Formation, includes Springville Shale and Chouteau Limestone in southern Illinois.

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone (Middle Devonian (Givetian) to Upper Devonian (Fammenian)) at surface, covers 1 % of this area

New Albany Shale, Blocher Shale, Sylamore Sandstone, Selmier Shale, Sweetland Creek Shale, Grassy Creek Shale, Saverton Shale, and Louisiana Limestone.

Carbondale Formation (Pennsylvanian (Moscovian to Kasimovian)) at surface, covers 0.5 % of this area

Carbondale Formation.

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone (Mississippian (Tourniaisian to Visean)) at surface, covers 0.3 % of this area

Meppen Limestone, Fern Glen Formation, and Burlington-Keokuk Limestone.

Shelburn-Patoka Formations undivided (Pennsylvanian (Kasimovian)) at surface, covers < 0.1 % of this area

Shelburn-Patoka Formations undivided.

Permian ultramafic intrusions (Permian) at surface, covers < 0.1 % of this area

Permian ultramafic intrusions.