The last glacial age ended about 13,000 years ago. As the climate rapidly warmed, nomadic hunters migrated to the New World from Asia across the dry land which is now the Bering Straight. Petroglyphs are mysterious artifacts of these people. Example of a Great Basin Curvilinear Petroglyph etched into a rock about 2-3000 yrs ago.
Abstract form indicates that the artist had a sophisticated artistic sense.
People who lived here fished and hunted in Lake Lahontan, which is now dry. A wall of petroglyphs at Petroglyph Point at Lava Bed National Monument, California overlooks Tule Lake and distant sacred Mount Shasta. When these carvings were made, the wall was next to the shore of Tule Lake. It is now easily accessible and is protected with a 100 yard fence. Pit and Groove Petroglyphs are older than 5000 years.