I was also curious about some of the 'historical evemts' mentioned in his posts. He (or someone responding) mentioned a battle at the Ohio Falls and then the Mandans moving to the upper Missouri river.

Now the only place that I have heard that story was in a fictional book "Children of the First Man" by Alexander Thom. It was a good read but entirely fictional account of Prince Madok and some followers crossing the Atlantic and arriving in the area of Mobile Bay. After surviving a hurricane they moved up the Tennessee river and settled for a few years before warfare with local tribes drove them out. Then they moved up the Ohio river to the falls and eventually had the same problem there. I seem to remember there are traces of stonework at those locations but hardly evidence of a Welsh colony.