Geologic units in Jackson county, Illinois

Tradewater Formation (Pennsylvanian (Bashkirian to Moscovian)) at surface, covers 43 % of this area

Tradewater Formation

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 14 % of this area

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

Carbondale Formation (Pennsylvanian (Moscovian to Kasimovian)) at surface, covers 11 % of this area

Carbondale Formation.

Shelburn-Patoka Formations undivided (Pennsylvanian (Kasimovian)) at surface, covers 9 % of this area

Shelburn-Patoka Formations undivided.

Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone) (Mississippian (Visean)) at surface, covers 4 % of this area

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

Tamms Group (Upper Silurian (Pridoli) to Lower Devonian (Emsian)) at surface, covers 2 % of this area

Tamms Group, includes Bailey Limestone, “Flat Gap Limestone”, Grassy Knob Chert, Backbone Limestone, and Clear Creek Formation.

Holocene series (Quaternary-Holocene Series) at surface, covers 0.3 % of this area

Alluvium - clay, silt, sand, and gravel.

St. Louis Limestone (Mississippian (Visean)) at surface, covers 0.2 % of this area

St. Louis Limestone.

Muscatatuck Group (Middle Devonian (Eifelian to Givetian)) at surface, covers < 0.1 % of this area

Muscatatuck Group, includes Grand Tower Limestone and St. Laurent (Alto and Lingle) Formation in southern Illinois; includes Detroit River Formation, Wapsipinicon Limestone, and Cedar Valley Limestone in northern and western Illinois.

Warsaw Formation and Salem Limestone (Mississippian (Visean)) at surface, covers < 0.1 % of this area

Warsaw Formation and Salem Limestone in western Illinois.