20 Oct: Our final destination on the way home was in western Pennsylvania, to see the archaeological site of the oldest evidence of human presence in North America. It was found in 1955 by a local man who kept his chance discovery of a few ancient artifacts secret until 1973, when the site could be carefully excavated and examined by archaeologists from the University of Pittsburgh. This kept it undisturbed by looters and souvenir seekers. The site was a natural rock overhang with layers of rocks, dirt, artifacts, and plant and animal remains that had accumulated to a depth of several feet over a period of about 16,000 years. It is invaluable not only because of the age, but also because the entire uninterrupted sequence was preserved unharmed from erosion and vandalism. The site appears to have been used frequently but temporarily throughout its long history, such as a camp for hunters or families moving through the area.
