Teeming with more than 300 species of invertebrates, fish, seabirds, and marine mammals, the Greyhound Rock State Marine Conservation Area on California’s central coast is a biodiversity hotspot. Giant kelp forests harbor abalone, juvenile rockfish, and a multitude of other marine invertebrates. Whales and dolphins feed offshore. Brown pelicans and Caspian terns dive for fish. And the bold red beak of the black oystercatcher flashes in the sun as it hunts for mussels and limpets in the rocky shallows.

When Snail Shells Were Currency

Around 300 to 500 years ago, purple olive snail shells (Olivella biplicata) could buy you nutritious seeds or a big hunk of tasty game meat. The shells were recognized by indigenous peoples throughout California as currency. This gave the Cotoni, who lived in the area around Greyhound Rock, a big trading advantage.

If you’re visiting the beach at Greyhound Rock, see if you can spot one of the smooth, oblong purple shells and try trading it with a fellow beachcomber for, say, a watch or smartphone. You probably won’t get more than a concerned look of confusion in return.

That transaction would have failed for the Cotoni, too, because for the snail shells to have any economic value, they had to be made into beads. The Cotoni dried the shells to remove the organic remains (snail guts), ground off the tips so they could be strung onto a cord, smashed the shells into smaller parts, and then reshaped the shell fragments by using a pump drill. They used the beads for trading but also as jewelry and as ornaments on clothing and weapons.

Money may not grow on trees, but for a time, it did wash up on shore for easy collecting at Greyhound Rock.

Take the Self-Guided Mobile Tour

This piece is part of the Santa Cruz Marine Protected Areas Beaches Tour made possible by the Santa Cruz Collaborative with support from the California Marine Sanctuary Foundation and the Resources Legacy Fund. Download the free app with many tours of the Santa Cruz area and beyond.

1. Sources

   • About MPAs: State of the Oceans. California MPAs website.
   • Personal communication with Martin Rizzo, PhD Candidate, Santa Cruz County, February 2016.
   • Tending the Wild: Native American Knowledge and the Management of California's Natural Resources, by M. Kat Anderson, University of California Press, 2005.
   • The Role of Olivella Shell Currency in a Burgeoning Prehistoric California Economy, by A. Rowan Gard. Prized Writing 2005-2006, UC Davis website.
   • Maps: The Move to the Missions. Amah Mutsun Tribal Band website.
   • A History of American Indians in California, by Dwight Dutschke. Office of Historic Presentation, California State Parks website.
   • Greyhound Rock, Santa Cruz. California State Beaches, See California website.

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