Caseyville Formation (ILPAcv;0)

State	Illinois
Name	Caseyville Formation
Geologic age	Pennsylvanian
Original map label	3820
Comments	mostly sandstone and gravel with minor shale, coal and underclay Secondary unit description from USGS Geologic Names lexicon (ref. IL002): Preferred usage of Illinois Geological Survey in 1975 is Caseyville Formation of McCormick Group. Primarily sandstone, siltstone, and shale. The sandstones are composed of quartz and very little clay and mica. Most contain quartz granules and pebbles, commonly less than half inch in diameter. The coarser sandstones reach about 100 ft thick and show relatively uniform cross-bedding with dip directions to the west, south, or southwest. Several coal seams, most somewhat lenticular, occur in the formation. Limestone is rare. The Caseyville is as much as 500 ft thick but 350 ft is common maximum. Unconformably overlies Mississippian rocks; underlies the Abbott Formation. Divided into Lusk Shale, Wayside Sandstone, Battery Rock Sandstone, Drury Shale, Sellers Limestone, Gentry Coal, and Pounds Sandstone Members. Based on the stratigraphic column on the 1967 paper map, the Caseyville Formation appears to consist of about 75% sandstone, 10% shale or clay, 5% coal, 5% underclay, and 5% gravel.
Primary rock type	sandstone
Secondary rock type	shale
Other rock types	coal; claystone; gravel
Lithologic constituents	Major Sedimentary > Clastic > SandstoneBased on the stratigraphic column on the 1967 paper map, the Caseyville Formation appears to consist of about 75% sandstone, 10% shale or clay, 5% coal, 5% underclay, and 5% gravel. Minor Sedimentary > Clastic > Mudstone > ShaleCaseyville Formation - Based on the stratigraphic column on the 1967 paper map, the Caseyville Formation appears to consist of about 75% sandstone, 10% shale or clay, 5% coal, 5% underclay, and 5% gravel. Incidental Unconsolidated > Coarse-detrital > GravelBased on the stratigraphic column on the 1967 paper map, the Caseyville Formation appears to consist of about 75% sandstone, 10% shale or clay, 5% coal, 5% underclay, and 5% gravel. Sedimentary > CoalBased on the stratigraphic column on the 1967 paper map, the Caseyville Formation appears to consist of about 75% sandstone, 10% shale or clay, 5% coal, 5% underclay, and 5% gravel. Sedimentary > Clastic > Mudstone > ClaystoneCaseyville Formation - Based on the stratigraphic column on the 1967 paper map, the Caseyville Formation appears to consist of about 75% sandstone, 10% shale or clay, 5% coal, 5% underclay, and 5% gravel.
Map references	Willman, H.B., and others, (compilers), 1967, Geologic Map of Illinois: Illinois State Geological Survey, scale= 1:500,000, paper.
Unit references	Willman, H.B., and others, (compilers), 1967, Geologic Map of Illinois: Illinois State Geological Survey, scale= 1:500,000, paper. USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Gallatin - Hardin - Jackson - Johnson - Mercer - Pope - Randolph - Rock Island - Saline - Union