[HamiltonJay]

One person may have, but that one person would not have left much of an archialogical trail.. remember we're talking archeology here... when they say spread to the 4 corners it means society and civilization spread to the 4 corners, not just a "lone gunman".

[RightWhale]

We might also assume some societal organization. The explorers would report back with fantastic tales of great spots they had found and individual clans would indeed pick up and migrate. To end up with 50 million in the Amazon basin just 1000 to 500 years ago would indicate a fairly large movement of population. I would imagine that once they reached America, they would explore the whole place immediately. Should we accept that the few archaeological sites we know would give a true picture of the nature of the populating of America?