Rick Greenwood, director of Corporate Environment, Health and Safety for Southern California Edison, poses with the fossilized leg bones of a precursor to the modern horse, in Riverside, Calif., Monday, Sept. 20, 2010.  Utility workers preparing to build a new substation in an arid canyon southeast of Los Angeles stumbled on a trove of animal fossils dating back 1.4 million years that researchers say will fill in blanks in Southern California's history. (AP Photo/Reed Saxon)