Humans May Have Occupied Western US Earlier Than Previously Thought

An ancient stone tool recently discovered in southeast Oregon suggests that humans may have occupied the western United States earlier than previously thought, the US Bureau of Land Management (BLM) announced Thursday.

Archeologists uncovered the tool eight inches under a layer of volcanic ash that dates back to the eruption of Mount St. Helens 15,800 years ago.

"When we had the volcanic ash identified, we were stunned, because that would make this stone tool one of the oldest artifacts in North America," Patrick O'Grady, with the University of Oregon Archaeological Field School, who led the excavations at Rimrock Draw Rockshelter where the tool was found, said in a statement.

Beneath the 12-foot layer of volcanic ash, researchers discovered a small orange tool that they believe was used for scraping animal hides, butchering, and possibly carving wood. Blood tests performed on the tool found residue consistent with bovine blood - most likely belonging to the species Bison antiquus, an extinct ancestor of the modern buffalo.

Until now, the so-called Clovis people were believed to be the oldest human residents in the western hemisphere, dating back to around 13,000 years ago. But this latest find would put humans at the site 1,500 years earlier, and may be the oldest signs of human occupation in the western United States to date.

"The discovery of this tool below a layer of undisturbed ash that dates to 15,800 years old means that this tool is likely more than 15,800 years old, which would suggest the oldest human occupation west of the Rockies," said Scott Thomas, BLM Burns District archaeologist.

Although this discovery has been described as "tantalizing," it should be considered as preliminary, as it has yet to be submitted to a scientific journal for publication.

"No one is going to believe this until it is shown there was no break in that ash layer, that the artifact could not have worked its way down from higher up, and until it is published in a convincing way," Donald K. Grayson, professor of archaeology at the University of Washington, told The Associated Press. "Until then, extreme skepticism is all they are going to get."

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