Professor of Anthropology George “Tom” Jones was part of a multi-authored report published in the July 13 issue of Science Magazine. The paper describes cultural stratigraphy, radiocarbon dates, stone tool technology and ancient DNA recovered from human coprolites (dessicated feces) at Paisley Caves, Oregon. This site contains the earliest directly dated human remains in North America. In addition, stone tools recovered from deposits that date between about 11,000 and 11,340 radiocarbon years ago provide evidence of a distinctive technological pattern that differs from contemporaneous Clovis tool technology, which has long been supposed to be the antecedent of all stone tool industries in North America. These results point to complex origins of early North American populations and independent technological developments.
Since the original reporting of the Paisley Cave finds there have been questions about the coprolites, in particular whether they are indeed attributable to humans and not to other animals and if the ages of the oldest ones at roughly 14,000 years are accurate or if the ages could be affected by some sort of contamination.
The research reported in this paper lays to rest any question about contamination--there seems to be little. Paired dates of sample materials like bone, wood, or coprolite and potential contaminants extracted from these samples give the same ages. So concerns that carbon might be moving through the sediments, carried by water or urine, and contaminating samples used for dating has no basis--the dates appear to be good. Additional extraction of DNA from the coprolites indicates they contain human DNA.
The second focus of the paper was the stone tools recovered from the deposits dating greater than 12,500 years ago. Elsewhere in North America artifacts of this age are attributable to the Clovis industry, which is distinctive for the presence of fluted projectile points and large blades. But at Paisley Caves the only diagnostic projectile points have a very different morphology than the Clovis point and are attributable to a technology known in the intermountain region as the Western Stemmed industry. (This industry appears to last for several thousand years after its first appearance.) It has been thought by many archaeologists that the Western Stemmed industry evolved from the Clovis industry. But the researchers found at Paisley Cave that Western Stemmed is fully contemporaneous with Clovis, suggesting they may be derived from a common technological ancester or perhaps from different human populations entering the North American interior from different entry points. Clovis may come from groups moving southward through a central corridor in Canada or perhaps from the Gulf Coast moving northward, while Western Stemmed may represent human groups moving inland from the Pacific coast.
What Jones did for this research project was to examine all of the fine flaking material that was a by-product of tool manufacture. Since some Clovis tools are made in a very specific sequence and produce flakes of distinctive morphologies, the researchers hoped to learn if any of the Paisley Cave flake assemblage could be attributed to these Clovis manufacture techniques. Jones’ examination of some 3,800 flakes failed to identify any specimens that were the result of Clovis techniques. He could not, however, say with certainty that these flakes clearly were by-products of a characteristic technique used to make Western Stemmed projectile points. In fact, Western Stemmed point manufacture is much more generalized and produces little of diagnostic value by way of flake by-products. Indeed, what Jones believes most of the flaking debris represent are the final steps in finishing the shape of tools used at the cave, things like knives and scraping tools, or steps taken to repair broken tools or resharpen tools that had become dull through use.