Modesto Formation (ILPAm;0)

State	Illinois
Name	Modesto Formation
Geologic age	Pennsylvanian
Original map label	2120
Comments	Siltstone and clay, limestone, coal, sandstone and includes the No. 8 coal, and the Piasa Limestone and Lonsdale Limestone members. Based on the stratigraphic column on the 1967 paper map, the Modesto Formation appears to consist of about 45% shale, 20% limestone, 20% sandstone, 10% clay, 5% coal and <5% black shale.
Primary rock type	shale
Secondary rock type	sandstone
Other rock types	limestone; clay or mud; coal; black shale
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > ShaleBased on the stratigraphic column on the 1967 paper map, the Modesto Formation appears to consist of about 45% shale, 20% limestone, 20% sandstone, 10% clay, 5% coal and <5% black shale. Includes the No. 8 coal, and the Piasa Limestone and Lonsdale Limestone members Minor Sedimentary > Carbonate > LimestoneModesto Formation - Based on the stratigraphic column on the 1967 paper map, the Modesto Formation appears to consist of about 45% shale, 20% limestone, 20% sandstone, 10% clay, 5% coal and <5% black shale. Includes the No. 8 coal, and the Piasa Limestone and Lonsdale Limestone members Sedimentary > Clastic > SandstoneModesto Formation - Based on the stratigraphic column on the 1967 paper map, the Modesto Formation appears to consist of about 45% shale, 20% limestone, 20% sandstone, 10% clay, 5% coal and <5% black shale. Includes the No. 8 coal, and the Piasa Limestone and Lonsdale Limestone members Incidental Sedimentary > CoalModesto Formation - Based on the stratigraphic column on the 1967 paper map, the Modesto Formation appears to consist of about 45% shale, 20% limestone, 20% sandstone, 10% clay, 5% coal and <5% black shale. Includes the No. 8 coal, and the Piasa Limestone and Lonsdale Limestone members
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.
Geographic coverage	Bond - Bureau - Cass - Champaign - Christian - Clark - Clinton - Coles - Crawford - Cumberland - De Witt - Douglas - Edgar - Ford - Franklin - Fulton - Gallatin - Greene - Hamilton - Henry - Jackson - Jasper - Jefferson - Jersey - Knox - La Salle - Lawrence - Livingston - Logan - McLean - Macon - Macoupin - Madison - Marshall - Menard - Montgomery - Morgan - Peoria - Perry - Piatt - Putnam - Randolph - Saint Clair - Saline - Sangamon - Schuyler - Stark - Tazewell - Vermilion - Wabash - Washington - White - Williamson - Woodford