Where is everyone? Anybody read the Nov. 2011 Scientific American that destroys Clovis First?

[csziggy]

There is now far too much evidence of at least several groups of humans arriving in the Americas prior to the classic Clovis points. The problem I see with the new information is that it seems to show that humans were pretty much all over both North and South America at about the same time. How did people get to those places without intermediary stops along the way?

My theory is that during the Ice Ages while the ocean levels were low, the coastal areas now underwater were the primary settlement points. Any evidence of people traveling is now under the ocean. As the climate warmed and the oceans rose, people had to move upland and into areas where they seem to have appeared all at the same time.