Stone tools and human DNA from ancient caves in Oregon offer new evidence of how some of the first Americans spread through the continent: quite apart from the better-known Clovis culture, a separate group that may have occupied the West.

Archaeologists said Thursday that using multiple techniques, they have dated broken obsidian spear points from Paisley Caves to about 13,200 years ago, as old as much different stone tools from the Clovis culture found in the southeast and interior United States. Radio-carbon dating of human DNA from coprolites — ancient desiccated human feces — shows people lived in the caves as early as 14,300 years ago.

The dates indicate that the Clovis style of chipping stone was not the mother of Stone Age technology, as others have theorized, and that the two styles were developed independently by different groups, said Dennis Jenkins, an archaeologist with the University of Oregon’s Museum of Natural and Cultural History who led the excavations. That development may have happened in the Ice Age region of Beringia, where Siberia and Alaska were linked, before the two groups migrated south, he said.

The findings by an international team of scientists from the U.S., Britain and Denmark were reported online Thursday in the journal Science.

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