LANZHOU, Nov. 19 (Xinhua) -- Chinese archaeologists have discovered remains of walls of three ancient cities dating back between 3,100 and 2,500 years ago in northwest China's Gansu Province.

    The remains were discovered in Xishan, Dabaozishan and Shanping, three different sites near the Lixian County seat of Gansu. They could be traced back to the Western Zhou Dynasty (1,100 BC - 771 BC) and the Spring and Autumn Period (770 BC - 476 BC).

    The sites of Xishan and Dabaozishan cover an area of about 100,000 square meters and 250,000 square meters respectively. The earthen city wall remains of the three sites were two to three meters high, and 300 to 1,200 meters long

    "Although they have been seriously damaged, the walls can tell us a lot about the production and life of the people prior to the Qin Dynasty (221 BC - 206 BC), the first united kingdom of China," said Wang Hui, deputy director of the Gansu Provincial Archaeological and Research Institute.

    Historical research showed that the Qin Dynasty people mainly lived in the eastern areas of Gansu Province before moving east and building the kingdom with its capital in Xianyang, which is near modern-day Xi'an.

    The new discoveries will be of value to the study of the ancestors of the Qin Dynasty, according to Wang.