Tom Lehman was researching rock layers at Texas' Rattlesnake Mountain in the 1980s when he discovered some weathered bones. He had no idea at the time, but the fossils represented the skull of a ...

CNN — Tom Lehman was researching rock layers at Texas' Rattlesnake Mountain in the 1980s when he discovered some weathered bones. He had no idea at the time, but the fossils represented the skull of a ...