Ancient mastodon hunt reveals North America's oldest culture

We know that humans reached North America between 40000 and 16000 years ago...and that's about all we know for certain. Anything in American prehistory before about 10000 years ago remains deeply controversial. But some mastodon bones found in the 1970s recently revealed major clues. » 10/20/11 2:30pm 10/20/11 2:30pm