Animal fossil in Hezheng County

An unidentified bird fossil is seen in Gansu Hezheng Ancient Animal Fossil Museum in Hezheng County, northwest China's Gansu Province, Aug. 11, 2011. Over 30,000 ancient animal fossils, dating back to between 2.5 million and 30 million years ago, have been unearthed around the county. (Xinhua/Wang Yanming) (zl) (zgp)

Chen Shanqin, deputy curator of the Gansu Hezheng Ancient Animal Fossil Museum, introduces a newly excavated animal fossil in Hezheng County, northwest China's Gansu Province, Aug. 11, 2011. Over 30,000 ancient animal fossils, dating back to between 2.5 million and 30 million years ago, have been unearthed around the county. (Xinhua/Wang Yanming) (zl) (zgp)