Terrace walls - from Norman Muller

Norman Muller writes (referring to Geophile's post on Eckville Terraces):

The image just posted on your website of terrace walls near the Delaware River reminds me of a large group of terrace walls that I saw on a mountain side in Blairsville, GA, about six years ago. There, the walls were dated to about 1000 AD by OCR dating.

Here are two pictures of the terraces, with Norman in the second picture.