Also known at the Kinkaid Limestone, this unit is made up of several smaller members. This unit ranges from 0' - 230 ' thick. The Grove Church Shale is at the top, followed by Members, Goreville Limestone, Cave Hill Shale, and Negli Creek Limestone.
Tobinsport Formation
A formation in Illinois containing 4 members that are linked to other formations in the Upper Pope Group. The Negli Creek Limestone of the Kinkaid formation to the west. Mt. Pleasant Sandstone, Bristow Sandstone, and Siberia Limestone. The Siberia is a thin tongue of the Menard formation.[5]
Degonia Formation
This sandstone unit is 0-150' thick.
Clore Formation
This unit is 0-150’ thick. Its units include the Ford Station Limestone, Tygett Sandstone and Cora Limestone Members.
The type section of both the Walche Limestone Member and the Scottsburg Limestone Member are exposures in Walche's Cut, a railway cutting on the Illinois Central Railroad.[6][7][8]
Waltersburg Formation
This formation is 0-100’ thick.
Vienna Formation
This limestone unit is 0-60' thick
Tar Springs Formation
This sandstone unit is 0-150' thick. The Tar Springs consists of interbedded sandstone and shale, creating closed reservoirs within the sand. For this reason it is the largest oil producing formation in Illinois. Estimated to have accounted for more than 60% of the oil production in the state.
^Droste, J. B., and Keller, S. J., 1995, Subsurface stratigraphy and distribution of oil fields of the Buffalo Wallow Group (Mississippian) in Indiana: Indiana Geological Survey Bulletin 63, 24 p.
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