What do you study? <a href=" http://luisamartelo.com/index.php/essay-contests-for-high-school-students-2013/#experience ">best essays writing service</a> "Whether they turn out to be as old as 14,800 years ago or as recent as 10,500 years ago, they are still the oldest petroglyphs that have been dated in North America," said Benson, a national research scientist emeritus for the U.S. Geological Survey and curator of anthropology at the University of Colorado Natural History Museum in Boulder.