Stone spearheads and human DNA found in Oregon caves, anthropologists say, have produced firmer evidence that these are the oldest directly dated remains of people in North America. They also show that at least two cultures with distinct technologies -- not a single one, as had been supposed -- shared the continent more than 13,000 years ago.
In other words, the Clovis people, long known for their graceful fluted projectile points, were not alone in the New World. The occupants of Paisley Caves, on the east side of the Cascade Range, near the town of Paisley, left narrow-stemmed spear points shaped by different flaking techniques. These hunting implements are classified as the Western Stemmed Tradition, previously thought to be younger than the Clovis technology.
The new research, based on the recent discovery of the artifacts and more refined radiocarbon dating tests, established that the cave dwellers who made the Western Stemmed points overlapped or possibly preceded the Clovis artisans elsewhere, the scientists reported in a paper published online by the journal Science.
"These two distinct technologies were parallel developments, not the product of a unilinear technological evolution," the research team, led by Dennis Jenkins of the University of Oregon, concluded. "The colonization of the Americas involved multiple technologically divergent, and possibly genetically divergent, founding groups."
Jenkins and colleagues did not discuss how the divergent technologies might be related to initial migration patterns. They only noted that the human DNA from the cave, extracted from coprolites, or dried feces, pointed to Siberian-East Asian origins of the people.
The findings lend support to an emerging hypothesis that the Clovis technology, named for the town in New Mexico where the first specimens were discovered, actually arose in what is now the Southeastern United States and moved west to the Plains and the Southwest. The Western Stemmed technology began, perhaps earlier, in the West. Most artifacts of that kind have been found on the West Coast and in Idaho, Nevada, Utah and Wyoming.
"We seem to have two different traditions coexisting in the United States that did not blend for a period of hundreds of years," Jenkins said.
Although other pre-Clovis sites have been claimed, only the 14,600-year-old Monte Verde campsite in Chile and now Paisley Caves have so far cleared most hurdles of critical review. When the first dating of human DNA from the caves was reported in 2008, some archaeologists worried that the coprolites may have been contaminated, possibly by the leaching of later DNA from humans and rodent urine.
So Jenkins returned to the caves in 2009 and each year since. Digging 5 to 6 feet into silt, the archaeologists uncovered the Western Stemmed points and not a single Clovis point. Any contaminating carbon was washed out.
Michael Waters, director of the Center for the Study of the First Americans at Texas A&M University, who was not involved in the research, said the Paisley Caves findings "really provide solid evidence that the two technologies are contemporaneous."