I too feel that perhaps the history of humans is much more complicated and ancient that seemed to be accepted until recently. It certainly seems that some human-like peoples co-existed for instance.

About how long ago is it now conventionally presumed that humans reached America? Which is the more popular view-- 15,000 or 30,000? It seems a big gap. Also, would it be more likely to have inhabitants earlier on one side of the country than the other? Are all the early humans the same type anthropologically, or are there differences? There were no Neanderthal-types were there?