Archaeological research on the distribution of exotic materials in ancient sites can sometimes trace the routes of exchange.

When a specific type of shell found at an inland site matches the chemical signature of shells from a specific coastal location — something that can sometimes be determined through trace element analysis — it identifies both the origin of the material and, implicitly, the existence of a connection between the inland site and that coastal location.

The Olivella shells found at some Texas Archaic sites are a particularly interesting case.

Olivella is a genus of small marine snail found on both the Pacific and Gulf coasts.