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Ancell Group

Ancell Group
State Illinois
Name Ancell Group
Geologic age Ordovician
Comments The formations in the Ancell group include: Joachim Dolomite, Dutchtown Limestone, St. Peter Sandstone, Glenwood Formation. Based on the stratigraphic column on the 1967 paper map, collectively this group is about 60% sandstone, 30% dolomite, and 10% limestone, and incidental anhydrite.
Primary rock type sandstone
Secondary rock type dolostone (dolomite)
Other rock types limestone; evaporite
Lithologic constituents
Major
Sedimentary > Clastic > SandstoneThe formations in the Ancell group include: Joachim Dolomite, Dutchtown Limestone, St. Peter Sandstone, Glenwood Formation. Based on the stratigraphic column on the 1967 paper map, collectively this group is about 60% sandstone, 30% dolomite, and 10% limestone, and incidental anhydrite.
Minor
Sedimentary > Carbonate > LimestoneThe formations in the Ancell group include: Joachim Dolomite, Dutchtown Limestone, St. Peter Sandstone, Glenwood Formation. Based on the stratigraphic column on the 1967 paper map, collectively this group is about 60% sandstone, 30% dolomite, and 10% limestone, and incidental anhydrite.
Sedimentary > Carbonate > DolostoneThe formations in the Ancell group include: Joachim Dolomite, Dutchtown Limestone, St. Peter Sandstone, Glenwood Formation. Based on the stratigraphic column on the 1967 paper map, collectively this group is about 60% sandstone, 30% dolomite, and 10% limestone, and incidental anhydrite.
Incidental
Sedimentary > Chemical > Evaporite > AnhydriteThe formations in the Ancell group include: Joachim Dolomite, Dutchtown Limestone, St. Peter Sandstone, Glenwood Formation. Based on the stratigraphic column on the 1967 paper map, collectively this group is about 60% sandstone, 30% dolomite, and 10% limestone, and incidental anhydrite.
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.
Counties Calhoun - Cook - DeKalb - Grundy - Kendall - La Salle - Lee - Monroe - Ogle - Stephenson - Winnebago