Middle Devonian (ILDm;0)

State	Illinois
Name	Middle Devonian
Geologic age	Devonian
Original map label	5880
Comments	The middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia.
Primary rock type	limestone
Secondary rock type	shale
Other rock types	dolostone (dolomite); sandstone; evaporite; sedimentary breccia;
Lithologic constituents	Major Sedimentary > Carbonate > LimestoneThe middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia. Minor Sedimentary > Carbonate > DolostoneThe middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia. Sedimentary > Clastic > Mudstone > ShaleThe middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia. Incidental Sedimentary > Clastic > Sedimentary-brecciaThe middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia. Sedimentary > Chemical > Evaporite > AnhydriteThe middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia. Sedimentary > Clastic > SandstoneThe middle Devonian includes the following formations: Cedar Valley Limestone, Wapsipinicon Limestone, Alto-Blocher Shale, Lingle Limestone, Grand Tower Limestone, Dutch Creek Sandstone. Based on the stratigraphic column on the 1967 paper map, this part of the Devonian collectively consists of about 50% limestone (locally cherty), 20% dolomite, 25% shale, and 5% sandstone, with incidental anhydrite and breccia.
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	Adams - Alexander - Calhoun - Champaign - Douglas - Ford - Greene - Hardin - Henderson - Henry - Iroquois - Jackson - Jersey - Mercer - Pike - Pulaski - Rock Island - Union - Warren