Largest neolithic ruins in China studied

City ruins found in northwest China\'s Shaanxi province covering more than a thousand acres are the largest ever found dating to neolithic China, scientists say. Archaeologists studying the 4,000-year-old Shimao Ruins in Shenmu County measured the exact size of the ancient stone city, China\'s state-run Xinhua News Agency reported Monday. \"The city has magnificent stone walls and we\'ve unearthed a large number of carved jade, which hint at the city\'s core status in north China\'s early civilization,\" Zhang Zhongpei, head of the Archaeological Society of China, said. The ruins were first found in 1976 and thought to be the remains of a small town, but a thorough survey last year led to the discovery of more city walls, officials said. Inner and outer structures were uncovered and the walls surrounding the outer city were found to cover an area of 1,050 acres.