Scientists have investigated how a seashell bead travelled 8,500 years ago

Scientists have studied two beads made from the shells of the giant rock scallop, *Crassadoma gigantea*. They were discovered during archaeological excavations at the Turkey Flat and Lichtenstein sites in the south-east of Monterey County in the USA.

These sites are located in the interior of California, approximately 68 kilometres from the nearest modern coastline. However, similar ornaments are most often found much further south — in the area of the Santa Barbara Strait and the Channel Islands.

The oldest bead was almost round. Radiocarbon analysis has shown that it is around 8,508 years old. The possible dating range is approximately 8,846 to 8,228 years ago. This is the earliest known example of a bead of this shape.

The second find turned out to be younger – it is around 3,674 years old.

Details

The age of the bead itself was only part of the mystery. The researchers were interested in how a decoration made from a seashell had ended up so far inland.

To answer this, the scientists analysed the chemical composition of the shells. Different sections of the ocean coastline leave slightly different chemical signatures in them, linked to the conditions of the water in which the mollusc grew.

It was not possible to definitively determine the place of origin for the younger bead. However, the results for the 8,500-year-old ornament pointed to Southern California.

If this assessment is correct, the shell could have travelled a distance considerably longer than the 68 kilometres separating the find site from the nearest coast.

One possible scenario is that the ornament was made in the Channel Islands or on the coast near Santa Barbara, after which it gradually moved northwards and further inland.

Such an object could have passed from one group of people to another and eventually ended up hundreds of kilometres from its place of origin.

However, it is impossible to reconstruct the exact route. Scientists also do not rule out the possibility that the bead was brought by a person who had travelled from the coastal region themselves.

The find therefore suggests long-distance connections between ancient communities, but does not in itself prove the existence of a permanent trade route.

The giant rock scallop lives in the sea, and its thick, hard shell is not easy to work with. Turning it into a small piece of jewellery would have required both time and skill.

In later times, such shells were used by the indigenous peoples of California as jewellery, valuable items of exchange, and objects of special social or ceremonial significance.

However, we cannot directly apply these interpretations to people who lived 8,500 years ago. Scientists do not yet know exactly what the bead meant to its owner.

Previously, beads made from giant rock scallops were mainly associated with much later periods in California’s history.

The situation began to change following discoveries on San Miguel Island. A piece of jewellery made from the same type of shell, dating back more than 8,000 years, had previously been found there. The new bead from Turkey Flat is comparable in age to that artefact, but is particularly significant because it was found far from the islands and the coast.

Thus, people were already using such marine shells to make jewellery as early as the beginning of the Holocene, and the objects themselves may have been distributed far beyond the areas where the molluscs were harvested.

Why this is important

The discovery allows us to view ancient California not as a collection of isolated settlements. As early as around 8,500 years ago, objects, materials or people themselves could have travelled between distant territories.

A single small bead is not enough to reconstruct the entire exchange system. However, its age and place of discovery indicate that links between coastal and inland communities existed a very long time ago.

That said, the authors remain cautious: it is not yet possible to say with certainty that the bead was specifically a commodity. It could have been a gift, a personal ornament, or may have passed from one owner to another several times.

Source

The researchers directly dated two beads made from the shell of Crassadoma gigantea, found at archaeological sites in the inland areas of the south-eastern district of Monterey. The bead from Turkey Flat was given a mean calibrated date of around 8,508 years ago, whilst the find from Lichtenstein was dated to around 3,674 years ago.

Study: Barry A. Price, Simone M. Schinsing, Jasmine B. Kidwell. AMS Radiocarbon Dating of Giant Rock Scallop Beads from the Interior of California’s Southern Coast Range.

Journal: California Archaeology, 2026.