Galena Group
Paleozoic Stratigraphy of the Upper Midwest, USA
Dates are approximate, and deposition occurred at slightly different times in different areas
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Ordovician
- Galena Group (454–446 Ma)
- ::Dubuque Formation (447–446 Ma)
- Wise Lake Formation (449.4–447 Ma)
- Dunleth Formation (452–449.4 Ma)
- Decorah Shale (454–452 Ma)
- Platteville Limestone / Group (455–454 Ma)
- Ancell Group (454–455 Ma)
- Glenwood Shale (~455 Ma)
- St. Peter Sandstone (~459–~455 Ma)
- --- Major Erosional Unconformity ---
- ::--- Major Erosional Unconformity ---
- Everton Dolomite (only in S. Indiana)
- --- Major Erosional Unconformity ---
- Dunleth Formation
- Prarie du Chien Group
- * Shakopee Dolomite
- * New Richmond Sandstone (only in S. Indiana)
- * Oneota Dolomite
- * Dunleth Formation
- * Gunter Sandstone
Cambrian
- ::Jordan Sandstone
- Potosi Dolomite
- Potsdam Supergroup/Potsdam Sandstone Megagroup
- Munising Group
- Davis Formation
- Franconia Formation
- Ironton Sandstone
- Galesville Sandstone
- Eau Claire Formation
- Mount Simon Sandstone
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The Galena Group or Galena Limestone refers to a sedimentary sequence of Ordovician limestone that was deposited atop the Decorah Shale. It is part of the Ordovician stratigraphy of the Upper Midwestern United States. It was deposited in a calm marine environment, and is fossiliferous.[1]
References