The article points out that more human coprolites have been discovered at these old levels. Also that through an amazingly comprehensive series of radiocarbon dates and chemical analysis of soil and coprolite samples, Jenkins has been able to conclusively prove that the coprolite dates are uncontaminated and accurate. Last year at the SAA meetings I saw a presentation Jenkins made on the work he and Tom Stafford had done on this, and though you had to admire their thoroughness, it was almost excrutiating to sit through.
The other interesting discovery related in the article has to do with the recovery of examples of a particular projectile point style known as Western Stemmed points. Three of these are shown in the picture above. Most of you probably know that we archaeologists use projectile point styles as "type fossils" that can give you at least a rough idea of how old a site may be. People spend a lot of time collecting the information on the dates and locations of particular projectile point styles or "types" recovered from securely dated contexts. This collated data is published in articles and sometimes guidebooks that show the geographical and chronological extent of each type.We do the same thing with other types of artifacts as well, notably ceramics and beads.
Back to Western Stemmed points. Up until recently, data collated about these points indicated that they were found in the far western US and that they dated to about 8 to 10,000 BP. This put them at the Pleistocene/Holocene boundary and they were seen as a late Paleoindian type. "Stemmers" (as some call them) most likely served as points on darts thrown by atlatls.
Jenkins has upset all of this conventional knowledge by finding these points in the oldest levels at Paisley Caves. There are also finds cited from other sites in the region supporting the position that Western Stemmed points date much older than we thought.This makes them actually an early Paleoindian type and the contemporary or even antecedent of the well known Clovis type, Jenkins goes on with some speculation that Western Stemmed points had their origins in the west and spread eastward over time, while Clovis points had their origins in the southeast and spread west. More work will be needed to support that. I'm sure part of this theory has its origins in the fact that at the SAA meetings last April, Dennis Stanford reported that he and his associates have located 150 Clovis sites in the DelMarVa peninsula at Chesapeake Bay. This work isn't published yet, but is a stunning discovey as well, showing that the majority of known Clovis sites are found in the southeast.
The picture at the top of the page only shows bases of three Western Stemmed Points found at Paisley Caves. Above is a picture of a complete one I found on a site in Malheur County, Oregon last summer, less than 100 miles from Paisley Caves. I was pretty excited when I found this as it meant I had a 10,000 year-old site. Now it may mean that's a 13,000 year-old site. Also if you look in this post I wrote last year, you'll see a picture of one we found on a site in California. In California, that type is usually referred to as a Lake Mojave point.