YINCHUAN, Nov. 30 (Xinhua) -- More than 300 items used by prehistoric people in their daily life 4,000 years ago were unearthed in northwest China's Ningxia Hui Autonomous Region.

Wang Xiaoyang, head of the archaeological team, said on Monday that the pieces were found in the Beiyuan relic site, where the excavation area covers 800 square meters.

The pieces include clay pots, basins, cups and knives, stone axes and chisels, as well as bone awls and needles. Archaeologists also found clamshells which they believed were used for decoration.

The Beiyuan relic site, covering 25,000 square meters, was first excavated in 2013. This year about 40 people, led by the Ningxia regional archaeological institute, conducted a second excavation to learn more about Neolithic culture and development in the region.

Experts searched 11 houses - one cave dwelling and ten kivas - 151 pits, three kilns and a tomb. The kivas were square in shape, with a round cooking range at the center and painted white with lime.