I thought that the theory that Native American populations were much higher at one time is very fascinating. Incidentally, it's possible that the Black Plague crossed the Atlantic somehow. That plague was certainly virulent enough to kill so many Indians. Or maybe it was the other way around, and the plague originated in the Americas and somehow traveled to Europe?

I was just looking at old designs of Irish ships a week ago - a new experience for me. They were not much bigger than rowboats, and the original covering on the hull was animal skin. But the old sailors from Ireland sailed them quite a long way out into the Atlantic. Julius Ceasar is quoted as having observed these Irish ships when he went to England. It seems plausible that similar ships belonged to people from Iceland. And therefore, some kind of contact between the ancient Americas and Europe cannot be ruled out.

Pete2