BEIJING, CHINA—At the Neolithic site of Shimao Ruins in northern China, archaeologists have unearthed the skulls of more than 80 young women who may have been sacrificed before they were buried in a mass grave. The skulls show signs of “being hit and burned,” according to Sun Zhouyong, deputy head of the Shaanxi Provincial Institute of Archaeology. The women may have been captives that were killed in a ceremony at the construction of the city’s wall some 4,000 years ago. The rest of their bodies have not been found.