More than 650 images adorn the boulders below, one of the largest concentrations of petroglyphs in the park. People who farmed the Puerco River Valley 650 to 2,000 years ago pecked these petroglyphs onto the rocks, leaving a legacy etched in stone. When rocks are exposed to the elements, a patina called desert varnish forms on the surface. Native people used sharp tools to chip into this veneer of iron and manganese oxides, clay minerals, and organic material, revealing the lighter colored rock beneath. The various shades of desert varnish are due to the amounts and ratio of minerals present. Blacker shades tend to be higher in manganese oxides, while redder tones indicated a higher amount of iron oxides. The great variety of petroglyphs on Newspaper Rock includes anthropomorphs, zoomorphs, katsinas, hands and tracks, and geometrics.
