Thanks Diana in Wisconsin, this is also this week's GGG Digest ping, may be a first for a "New World" news story, btw. Great find!
The prehistory of the Copper Country, long haunted by tales of a bygone race has yet to be told. Few Americans are even aware of the extensive mining activity that took place on Isle Royale in Lake Superior or along the Trap Range of the Upper Peninsula where approximately 500,000 tons of pure copper were mined out sometime between 1800 and 1200 B.C.
Curiously, the tablet and figurines were apparently destroyed.