The same as with the Silurian, there is not a lot of evidence of activity from the Devonian period in Minnesota. An exception is a carbonate unit called the Cedar Valley formation in southern Minnsota. The material was deposited by the advance, then the withdrawal, of marine waters. Most of the fossil evidence has been obliterated. Elsewhere in the world there is fossil evidence of bizarre fish types, swamps and forests, and primitive amphibians. It is a fascinating era, for anyone who enjoys reading about the earth's history.
I have received two boxes of rocks and minerals in trade, from contacts I made at Dirty Rockhounds, a site for earth science enthusiasts. Beautiful quartz from SC (Diamond Hill Mine), and others from a collector in WV. Now I have to do a good job of selecting items for my end of the trade :)