File photo shows phytoliths, microscopic silica structures found in plants which persist long after the rest of the plant has decayed, found in the Dongyang site in Weinan City, northwest China's Shaanxi Province. Chinese paleontologists believe rice cultivation arrived in northern China from the south during the Neolithic age. Researchers with the Chinese Academy of Sciences institute of vertebrate paleontology and paleoanthropology base their view on study of items found in the Dongyang site. Phytolith analysis of residue found at the Dongyang site shows rice was grown there 5,800 years ago. (Xinhua)