Rock art consists of petroglyphs, pictographs, and geoglyphs.
Petroglyphs are images carved or pecked on rocks or rock walls. Pictographs are painted onto the rocks, using brushes, fingers or even spraying paint with the mouth. Geoglyphs, sometimes called intaglios, are images made in the desert floor by scraping away stones to make a design. Most of these Native Americans have an unbroken tradition associated with rock art sites, and consider them sacred. Remember, rock art is the expression of the belief system of an ancient culture.