http://philipcoppens.com/copper.html
Interesting article from the late 90's on a subject which has always fascinated me,but about which I know next to nothing.
The prehistoric Great Lakes copper mines.
Copper artifacts are not-to the best of my knowledge-found often,or in any quantity-in North American archaeological digs. Beyond the level of the occasional bracelet,or shirt button,there aren't any.
And yet,someone went to a hell of a lot of trouble to find copper,dig it up,and take it somewhere. So who did the digging,who did the shipping,and where did it go?
A very cool puzzle.
Edit:just now noticed that the link was in the title block and changed that....