There is no native copper in the Cahokian region. Presumably it came from the deposits in Upper Michigan, showing that long-distance trade was going on in those days, when there were no highways or railroads. Really remarkable.
“showing that long-distance trade was going on in those days, when there were no highways or railroads. Really remarkable.”
No highways - just the Mississippi, Missouri, Ohio & Tennessee rivers, and then Lake Michigan itself, - just to mention a few non-highways that were well traveled “back in the day”.
http://www.mapsofworld.com/north-america/rivers-and-lake.html
Yes, the copper comes from Michigan, but can be found along prehistoric trade routes that extend all the way to Charleston, SC, and down to beyond Valdosta, GA during this time frame. Also, ceramics from the Savannah River area can be found up near Michigan. The same exact people lived in at least two sites on the far opposite ends of that trade route, with more found every year....They got around...