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St. Peter Sandstone

Coarse to fine, rounded, frosted sand grains; minor green shale stringers.
State Iowa
Name St. Peter Sandstone
Geologic age Phanerozoic | Paleozoic | Ordovician-Early [Chazyan]
Comments Approx thickness 110 ft
Primary rock type sandstone
Secondary rock type shale
Other rock types
Lithologic constituents
Major
Sedimentary > Clastic > Sandstone (Bed)
Minor
Sedimentary > Clastic > Mudstone > Shale (Bed)
Map references
Hershey H. G. 1969, Geologic Map of Iowa: Iowa Geological Survey, scale 1:500K
Unit references
Hershey H. G. 1969, Geologic Map of Iowa: Iowa Geological Survey, scale 1:500K
Counties Allamakee - Clayton - Dickinson - Dubuque - Winneshiek