I've been reading these pages for years and always find something new. James Q. Jacobs is/was an academic instructor in Arizona, and he's got the best rock-art pages, photos and graphics on the web. His site isn't as irreplaceable as the rock art itself, but it is very rare.

Jacobs' interests in the ancient Americas are embracing enough to include the rock art of the American southwest, the archeology and iconography of Mesoamerica and the Andes, and the earthworks of eastern North America, all illustrated with his photographs and graphics.