The Hemudu culture was a Neolithic culture that flourished just south of the Hangzhou Bay in Jiangnan in modern Yuyao, Zhejiang, China. The culture may be divided into early and late phases, before and after 4000 BC respectively. The site at Hemudu, 22 km northwest of Ningbo, was discovered in 1973. Hemudu sites were also discovered at Tianluoshan in Yuyao city, and on the islands of Zhoushan. Hemudu are said to have differed physically from inhabitants of the Yellow River sites to the north. Some authors propose that the Hemudu Culture was a source of the pre-Austronesian cultures.