Cambrian (ILCA;0)

State	Illinois
Name	Cambrian
Geologic age	Cambrian
Original map label	8550
Comments	The following formations are included in this unit: Eminence Dolomite, Potosi Dolomite, Franconia Formation, Ironton Sandstone, Galesville Sandstone, Eau Claire Formation, Mt. Simon Sandstone. Based on the stratigraphic column on the 1967 paper map, the Cambrian units collectively represent about 70% sandstone, 25% dolomite, and 5% shale and siltstone. Locally the sandstone may be coarse.
Primary rock type	sandstone
Secondary rock type	dolostone (dolomite)
Other rock types	shale; siltstone
Lithologic constituents	Major Sedimentary > Clastic > SandstoneThe following formations are included in this unit: Eminence Dolomite, Potosi Dolomite, Franconia Formation, Ironton Sandstone, Galesville Sandstone, Eau Claire Formation, Mt. Simon Sandstone. Based on the stratigraphic column on the 1967 paper map, the Cambrian units collectively represent about 70% sandstone, 25% dolomite, and 5% shale and siltstone. Locally the sandstone may be coarse. Minor Sedimentary > Carbonate > DolostoneThe following formations are included in this unit: Eminence Dolomite, Potosi Dolomite, Franconia Formation, Ironton Sandstone, Galesville Sandstone, Eau Claire Formation, Mt. Simon Sandstone. Based on the stratigraphic column on the 1967 paper map, the Cambrian units collectively represent about 70% sandstone, 25% dolomite, and 5% shale and siltstone. Locally the sandstone may be coarse. Incidental Sedimentary > Clastic > Mixed-clastic > Siltstone-mudstoneThe following formations are included in this unit: Eminence Dolomite, Potosi Dolomite, Franconia Formation, Ironton Sandstone, Galesville Sandstone, Eau Claire Formation, Mt. Simon Sandstone. Based on the stratigraphic column on the 1967 paper map, the Cambrian units collectively represent about 70% sandstone, 25% dolomite, and 5% shale and siltstone. Locally the sandstone may be coarse.
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	DeKalb - Lee - Ogle - Winnebago