A team of archeologists working near Riley, Oregon report the discovery of a variety of items indicating human settlement of the region. To date these include spearheads or arrowheads, along with “tooth enamel fargments” believe to belong to a prehistoric camel, that became extinct approximately 13,000 years ago.

The most important discovery, however, was a small stone shaping tool, buried beneath a layer of volcanic ash. According to the researchers, the ash was a product of an eruption of Mt. St. Helens about 15,000 years ago.

The tool discovered is described as a “small orange agate tool believed to have been used for scraping animal hides, butchering, and possibly carving wood.”

Blood residue analysis conducted on the scraping tool revealed animal proteins which most likely came from an Bison antiquus, an extinct ancestor of modern buffalo.

“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, Bureau of Land Management (BLM) Burns District archaeologist in a statement.

The current site of the oldest known human settlement in North America, Paisley Cave, is also in Oregon. In 2008 a team of archeologists used DNA in human feces to date that site to approximately 12,000 BCE or 14,000 years ago. The new discovery stands to pin an even earlier date on settlement in the region.

“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. Given those circumstances and the laws of stratigraphy, this object should be older than the ash. While we need more evidence before we can make an irrefutable claim, we plan to expand our excavation this summer and hopefully provide further evidence of artifacts found consistently underneath that layer of volcanic ash. That’s the next step,” said Dr. Patrick O’Grady, of the University of Oregon Archaeological Field School.

At this point, however, the discovery is not without its skeptics.

“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,” he said. “Until then, extreme skepticism is all they are going to get,” Donald K. Grayson, professor of archaeology at the University of Washington told the Associated Press.

The BLM and University of Oregon teams are confident, however, that additional evidence will be found when the work continues this summer.

“For years, many in the archaeological field assumed that the first humans in the western hemisphere were the Clovis people – dating to around 13,000 years ago. While a handful of archaeological sites older than Clovis cultures have been discovered in the past few decades, there is still considerable scrutiny of any finding that appears older. With the recent findings at Rimrock Draw Shelter, we want to assemble indisputable evidence because these claims will be scrutinized by researchers. That said, the early discoveries are tantalizing,” said Stan McDonald, BLM’s lead archeologist for Oregon and Washington.