XI'AN, Oct. 21 (Xinhua) -- Archaeologists have found three tombs with remains of human sacrifice during an excavation of a large-scale cemetery linked to ruins from the Shimao culture dating back 4,000 years in Yulin City, northwest China's Shaanxi Province.

The stone settlement where the cemetery was found is known as Zhaishan ruins. It covers an area of about 1 million square meters and is about 60 km away from the Shimao site.

Each of the three tombs has a wooden coffin placed in a rectangular vertical pit grave measuring 10 square meters.

The occupants of the tombs were found in the coffins with jade items, while human sacrifices, all females based on preliminary identification, lay on their right side facing the tomb occupants, said Shao Jing, in charge of the Zhaishan archaeological project.

Marks of chop wounds were found on the women's remains, suggesting they had been immolated and buried with the tomb occupants, Shao said.

Archaeologists also discovered lune-shaped niches on the right side of the tombs, in which five-piece sets of pottery wares with stone lids were found together with stone knives.

Compared with other tombs found in the settlement, the three tombs are larger, with a more complex structure and more burial objects, Shao said, adding that the findings are important for the study of funeral customs and class consciousness of the 4,000-year-old culture.