[Vigilanteman]

The dates confirm “that hunter-gatherers [were] highly innovative,” she says, and willing to “regularly experiment with novel materials.”

Hunter-gatherers were also part-time farmers much earlier than archeologists used to beleive. They also traded more widely than archeologists used to beleive.

The best known agricultural tribe in what is now North Dakota is the Mandan, a Siouxian cousin tribe, that begin to arrive and grow corn, beans and squash around 1350 a.d. in the Knife River Valley.

But they weren't the first, just the largest and the most famous. Copper culture artifacts once thought unique to the Great Lakes Region and related to corn growing have been found elsewhere in North Dakota at least two centuries before the Mandan begin to arrive from the Ohio Valley.

[gleeaikin]

I remember reading that some early US explorers of the West who were Welsh ancestry said they could communicate with the Mandan using Welsh.