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Pleasanton Group

Shale with some sandstone, thin limestone beds and minor coal; Exline Limestone near top Chariton Conglomerate at base. .
State Iowa
Name Pleasanton Group
Geologic age Phanerozoic | Paleozoic | Carboniferous Pennsylvanian-Late [Missouri]
Comments Approx. thickness 40 ft. Revised to include three formations which are, in ascending order: Seminole, Lees Summit (new), and Shale Hill (new) Formations. Intra-Pleasanton unconformity occurs at base of Shale Hill. Unit and its divisions occur in western MO and southern IA, Forest City basin, Iowa shelf, and Lincoln anticline. (Howe, 1982).
Primary rock type shale
Secondary rock type sandstone
Other rock types limestone; coal
Lithologic constituents
Major
Sedimentary > Clastic > Mudstone > Shale (Bed)
Minor
Sedimentary > Clastic > Sandstone (Bed)
Sedimentary > Carbonate > Limestone (Bed)
Incidental
Sedimentary > Coal (Bed)
Map references
Hershey H. G. 1969, Geologic Map of Iowa: Iowa Geological Survey, scale 1:500K
Unit references
Hershey H. G. 1969, Geologic Map of Iowa: Iowa Geological Survey, scale 1:500K
Howe, W. B., 1982, Stratigraphy of the Pleasanton Group, Pennsylvanian System in Missouri: Missouri Department of Natural Resources, Open File Report Series OFR-82-IO-GI.
Counties Adair - Appanoose - Audubon - Cass - Crawford - Dallas - Decatur - Guthrie - Monona - Monroe - Shelby - Warren - Wayne