Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay
Ordovician - Sinnipee Group
The Sinnipee group consists of three formations, all dolostone. From top to bottom they are the Galena, Decorah and Platteville. They form escarpments here and there but are not as prominent as the Niagara Escarpment because of burial by glacial deposits.
Created 11 Sep 1997, Last Update 11 January 2020