Galena Group

Paleozoic Stratigraphy of the Upper Midwest, USA; Dates are approximate, and deposition occurred at slightly different times in different areas;
	Ordovician :Maquoketa Group (446–440 Ma) :Galena Group (454–446 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 --- ; :Knox Supergroup Cambrian; :Knox Supergroup (ct'd) Potsdam Supergroup/Potsdam Sandstone Megagroup; Munising Group; Davis Formation; Franconia Formation; Ironton Sandstone; Galesville Sandstone; Eau Claire Formation; Mount Simon Sandstone;

Galena Group
Stratigraphic range: Ordovician
Galena Group; Stratigraphic range: Ordovician
Type	Group
Sub-units	Platteville Limestone
Underlies	Dubuque Formation
Overlies	Decorah Shale
Location
Country	United States
Extent	Minnesota

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

Mossler, J. and Benson, S., 1995, 1999, 2006, Fossil Collecting in the Twin Cities Area. Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota.

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[TC-1] Mossler, J. and Benson, S., 1995, 1999, 2006, Fossil Collecting in the Twin Cities Area. Minnesota at a Glance: Minnesota Geological Survey: University of Minnesota.