13,000-Year-Old Stone Tool Cache in Colorado Shows Evidence ...     A biochemical analysis of a rare Clovis-era stone tool cache recently unearthed in the city limits of Boulder, Colo., indicates some of the implements were used to butcher ice-age camels and horses that roamed North America until their extinction about 13,000 years ago, according to a University of Colorado at Boulder study.     http://www.colorado.edu/news/r/1124c0243883c267a7759da4bc4a2...     tags: Mahaffy caveman