Upper Pope Group (Tar Springs Sandstone through Kinkaid Limestone).
Shelburn-Patoka Formations undivided.
Lower Pope Group (Aux Vases Sandstone through Glen Dean Limestone).
Tamms Group, includes Bailey Limestone, “Flat Gap Limestone”, Grassy Knob Chert, Backbone Limestone, and Clear Creek Formation.
Alluvium - clay, silt, sand, and gravel.
St. Louis Limestone.
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 in western Illinois.