What archaeologist Dennis Jenkins found in the Paisley Caves in south central Oregon may turn on its head the theory of how and when the first people came to North America.

Many scientists believe humans first came to this continent 13,000 years ago across a land bridge from Asia and they started the so-called Clovis culture. But Jenkins says they may have been living in these caves 1,000 years earlier, toward the end of the last ice age. “We certainly knew that people had lived in the caves, but we did not have adequate dating to prove that they were here at the end of the ice age,” he said.

In 2002, Jenkins and his students at the University of Oregon began excavating the caves looking for proof.

NewsHour has a video report about what Jenkins’ team found.