TRACCE no. 9 – by Robert Alan Clouse
2nd International Congress of Rupestrian Archaeology
2-5 October 1997 DARFO BOARIO TERME
Pattern and Function at Jeffers Petroglyphs, Minnesota, USA.
The Jeffers Petroglyphs site in the Midwestern United States contains over 2,000 recorded carvings, some of which likely date to 5,000 B.P.