The survey revealed that these settlements spanned from about 2800 BC in the late Yangshao period to around 1000 BC in the Shang and Zhou (1046-221 BC) dynasties.
Mostly distributed along riverbanks, the stone fortresses were surrounded by numerous ordinary settlements without defensive stone walls, indicating a clear clustered relationship, said Ma Mingzhi, head of the team.
The development of these stone fortresses shows a clear evolution from small to large in scale, from simple to complex in layout, and from rudimentary to mature in construction techniques — with social hierarchy becoming increasingly distinct.
The survey provides crucial information for a comprehensive understanding of the origin, development, spread and evolution of prehistoric settlements in northern China, Ma added.