A team of archaeologists and its trusty drone are revealing an island community that once supplied valuable beads to the inland towns of the Mississippian culture, which thrived in the eastern United States from 800 to about 1600 CE.

The supply end of an ancient trade network

A drone armed with laser beams discovered the remains of a long-lost culture on Raleigh Island, off the north coast of Florida. The high-resolution aerial laser scans mapped a massive complex of 37 oyster-shell rings, 23m to 136m across—the kind of rings that build up around coastal settlements through years of people eating oysters and discarding the shells. Some of the rings stood less than a meter high, but others loomed four meters above their surroundings. They formed four cloverleaf-shaped clusters, each with between six and 12 shell rings arranged around the one in the center.

“Given the general size and shape of the shell rings, we suspect each was the locus of a house and household of five to eight people each,” University of Florida archaeologist Kenneth Sassaman told Ars Technica. Assuming all the rings were used at about the same time, that means 200 or 300 people once lived on the long, low-lying 30-hectare island—and it looks like every household on the island was involved in making beads from lightning whelk shells.