Hunting Down the First Americans
James Adovasio stood on a platform on an overcast day last week, about forty feet up the side of a steep-sloped, wooded valley outside the tiny town of Avella, Pennsylvania, about thirty miles southwest of Pittsburgh. Adovasio, a sixty-nine-year-old archaeology professor, watched as a handful of archaeologists, mostly young ones, gently probed and poked at slabs of exposed rock. Torrential rains in mid-July had partially flooded the site, known as the Meadowcroft Rockshelter, and the group was here to assess the damage.
Adovasio began excavating this site back in 1973. A young archaeologist at the University of Pittsburgh, he intended to use Meadowcroft to train students. But what he found here helped demolish his colleagues’ long-held ideas about the timing of humans’ first steps in the New World. Since the nineteen-thirties, the conventional wisdom had held that humans crossed over into North America from Siberia around thirteen thousand years ago, then spread over the next five hundred years through North and South America—wiping out mammoths, mastodons, and other large mammals as they went. This hypothesis became known as the “blitzkrieg model” of species extinction.