AVELLA, Pennsylvania (AP) -- Evidence that humans inhabited western Pennsylvania some 16,000 years ago -- thousands of years earlier than most scholars believe -- is still dividing archaeologists, 30 years after blade tools and materials to make beads were found in a rock shelter.

Archaeologist J.M. Adovasio and his crew began to unearth the artifacts in the summer of 1973 at the Meadowcroft Rockshelter, about 25 miles southwest of Pittsburgh. Those findings challenged for the first time a belief cemented in the 1950s that humans had crossed the Bering Strait and first settled near Clovis, New Mexico, about 12,000 years ago.

Adovasio says skepticism over his findings has slowly dissipated over the last three decades, because of extensive study, dozens of radiocarbon tests and the discovery of other sites in North and South America.

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