Carbon 1213 dating
The rocks are located on the coast of Sonoma County about 75 km north of San Francisco, within Sonoma Coast State Beach, a unit of the California State Park System.
To date, I have located six sites consisting of one or more rubbing rocks, all within an area about 4 km in diameter.
The single deep excavation unit revealed quarry debris to 220 cm, and several possible hammerstone spalls were found at 200-220 cm.
The auger test made in the same unit recovered what may prove to be small pieces of quarry shatter to 340-350 cm.
During the summer and fall of 2003, one of the units was expanded into a 4x4 m block exposure (Fig. The spring 2004 crew worked on the 4x4 m exposure, and also excavated three 1x1 m units at CA-SON-365/H, a shellmidden located 100 m south of the jasper outcrop.
Over the past two years, I have developed what I term, “The Rancholabrean Hypothesis.” Simply put, the hypothesis proposes that elements of the Rancholabrean landscape (e.g., megamamal rubbing rocks and wallows) still survive and can be detected on the contemporary landscape.
Furthermore, by identifying these Pleistocene features, it may be possible to map the archaeological presence of the area’s first people.
Since the initial discovery of the Sonoma Coast rubbing rocks, a loose-knit team of researchers (including archaeologists, geologists, paleontologists, geomorphologists, pedologists, physicists, chemists, zoologists, botanists, and molecular biologists) have been working with me to confirm or deny the Rancholabrean Hypothesis.
(2) The following is an update on some of the progress that we have made to date as well as our plans for future research.
Archaeological Investigations at Jasper Rock Since 2003, archaeological excavations have been underway at Jasper Rock, a highly-polished jasper outcrop with evidence of past quarrying.