Excavators from the Australian National University School of Archaeology and Anthropology, digging at a site in southern Vietnam called Rach Nui, uncovered settlements along the Mekong Delta that were part of a network that manufactured and circulated large volumes of items over hundreds of miles.

The research, published in the journal Antiquity, contradicts previous thinking that the stone tools in the area were manufactured near stone sources in interior areas.

“But this shows evidence for a major trade network that also included specialist toolmakers and technological knowledge. It's a whole different ball game.

"This isn't a case of people producing a couple of extra items on top of what they need. It's a major operation."

Frieman said she found a sandstone grinding stone at Rach Nui that is believed to have come from a quarry more than 50 miles away.

"The Rach Nui region had no stone resources,” she said, “so the people must have been importing the stone and working it to produce the artifacts. People were becoming experts in stone toolmaking even though they live nowhere near the source of any stone.”

"In southern Vietnam,” said Dr. Philip Piper, who also participated in the project, “there are numerous archaeological sites of the Neolithic period that are relatively close together, and that demonstrate considerable variation in material culture, methods of settlement construction and subsistence….

"Various complex trading networks emerged between these communities, some of which resulted in the movements of materials and manufacturing ideas over quite long distances."