Donald K. Grayson, professor of archaeology at the University of Washington, said the scientific community would be skeptical.
“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.”
Two pre-Clovis sites are well documented and generally accepted by scientists, Grayson said. One is Paisley Cave, located about 60 miles southwest of the Rimrock site. The other is Monte Verde in Chile. Both are dated about 1,000 years before the oldest Clovis sites.
If the date of Rimrock holds up, it would put people at the site about 1,500 years earlier, at the end of the Pleistocene era, when mastodons, mammoths, camels, horses and bison roamed the area.
The find has yet to be submitted to a scientific journal for publication, but it has been reported in newsletters and at conferences, Thomas said.
Thomas found the site several years ago, while taking a break from carrying supplies to a session of the University of Oregon Archaeological Field School nearby that O’Grady was overseeing.
Thomas said he noticed an outcropping of an ancient lava flow, with very tall sage brush growing in front of it, indicating very deep sediment deposits. The soil was black in front of the rock, indicating someone regularly built cooking fires there for a long time. An ancient streambed ran by, which would have given people more reason to stay there. And on the surface, he found a stone point of the stemmed type, found at sites both older and younger than Clovis. Similar points have been found at Paisley Cave.
Volunteers looking around the surface found 30 stemmed points, and the field school started excavations in 2011, O’Grady said. Uncovered above and below the volcanic ash layer were fragments of teeth believed to be from ancient camels.
Tests by Archaeological Investigations Northwest Inc. of Portland on blood residue on the agate scraper were consistent with the bovid family of animals, Thomas said. The most likely bovine animal living in Oregon at that time would have been an ancestor of the buffalo.