Galena-Decorah-Platteville Formations (IAOgdp;0)

Galena FM- dolomite, minor limestone; chert in lower half. Approx thickness 230 ft. Decorah FM- brown limestone and dolomite; gray-green and brown shales at top and base. Approx thickness 60 ft. Platteville FM- fossiliferous gray limestone and brown dolomite; grayish-green shale at base (Glenwood). Fine- to medium-grained sandstone occurs above the Glenwood in the subsurface of southeastern Iowa. Approx thickness 110 ft

State	Iowa
Name	Galena-Decorah-Platteville Formations
Geologic age	Phanerozoic \| Paleozoic \| Ordovician-Middle [Mohawkian]
Original map label	Ogdp
Primary rock type	dolostone (dolomite)
Secondary rock type	limestone
Other rock types	shale; sandstone; chert
Lithologic constituents	Major Sedimentary > Clastic > Mudstone > Shale (Bed) Sedimentary > Carbonate > Limestone (Bed) Sedimentary > Carbonate > Dolostone (Bed) Minor Sedimentary > Chemical > Chert (Bed) Sedimentary > Clastic > Sandstone (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
Geographic coverage	Allamakee - Clay - Clayton - Delaware - Dubuque - Fayette - Howard - Jackson - Kossuth - Winnebago - Winneshiek