I recall reading about this some in the book 1491, which is quite interesting, and talks about how the Americas were prior to Columbus.<p><a href="http:&#x2F;&#x2F;amzn.to&#x2F;1HQYgSY" rel="nofollow">http:&#x2F;&#x2F;amzn.to&#x2F;1HQYgSY</a>