Science / Medicine : Tools Called Oldest in U.S.

An archeologist says he has dug up primitive tools that suggest humans lived in North America 13,500 years earlier than the date commonly accepted by scientists.

Don Wyckoff, director of the Oklahoma Archaeological Survey, said last week that he is convinced that his preliminary dating is accurate, but that extensive testing is needed to prove the age of the tools unearthed along with bison bones at a site near Alva, Okla., in September.

Carbon-dating tests on the bones were inconclusive, but Wyckoff said the same test on snail shells found at the same level indicates an age of 25,000 years. Based on current evidence, scientists have thought that ancient humans first lived in North America 11,000 to 11,500 years ago.

Experts say carbon testing on snail shells can be inaccurate because snails incorporate old carbon molecules in their shells. “These are the kind of dates that often turn out to be inaccurately old,” said Donald Grayson, professor of archeology at the University of Washington.

Wyckoff acknowledges the problem, but said he is confident that the discovery 30 miles west of Alva in northwest Oklahoma will prove to be the oldest evidence of human inhabitation of North America.

Wyckoff reported on his initial findings recently at a meeting of the Plains Anthropological Conference in Wichita, Kan.