THE mystery over when humans first populated the Americas continues to deepen. The latest date for rocks near Puebla, Mexico, which were said to bear fossilised human footprints, contradicts the suggestion made in July that humans reached the Americas 40,000 years ago. If people had indeed arrived this early then we would have to rethink everything we know about the history of early human migration.
Silvia Gonzalez of Liverpool John Moores University, UK, surprised the world’s media in July at a Royal Society exhibition in London by suggesting that markings found in a layer of ancient volcanic ash near…
