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Geologic units in Randolph county, Illinois

Additional scientific data in this geographic area

Lower Chesterian (Glen Dean - Renault) Series (Mississippian) at surface, covers 38 % of this area

Lower Chersterian (Glen Dean - Renault) Series

Carbondale Formation (Pennsylvanian) at surface, covers 22 % of this area

Carbondale Formation

Upper Chesterian (Grove Church - Tar Springs) Series (Mississippian) at surface, covers 21 % of this area

Upper Chesterian (Grove Church - Tar Springs) Series

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

Spoon (includes Pa in northeast)

Upper Valmeyeran (Aux Vases, Ste. Genevieve, St. Louis) Series (Mississippian) at surface, covers 6 % of this area

Upper Valmeyeran (Aux Vases, Ste. Genevieve, St. Louis) Series

Middle Valmeyeran (Salem, Warsaw, Borden, Springville; includes thin Mvl and Mk in south and east) Series (Mississippian) at surface, covers 3 % of this area

Middle Valmeyeran (Salem, Warsaw, Borden, Springville; includes thin Mvl and Mk in south and east) Series

Lithology: limestone; siltstone; shale

Lower Valmeyeran (Keokuk-Sedalia) Series (Mississippian) at surface, covers 1 % of this area

Lower Valmeyeran (Keokuk-Sedalia) Series

Lithology: limestone; shale

Galena-Platteville Groups (Ordovician) at surface, covers 0.6 % of this area

Galena-Platteville Groups

Caseyville Formation (Pennsylvanian) at surface, covers 0.5 % of this area

Caseyville

Modesto Formation (Pennsylvanian) at surface, covers 0.3 % of this area

Modesto Formation

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

Abbott Formation