Periaster sp.
Echinoid
Paleocene
Locatelli Formation
Santa Cruz Mountains, California, USA

24mm echinoid. Very rare.

Periaster is a genus of sea urchin better known from the Middle Cretaceous (Cenomanian) of France.  Its occurrence in the Paleocene of California suggests a fossil record largely unknown.

You can collect this site for two hours and find nothing.  Another two hours later, you might have one or two. When you find one, they usually exhibit some crushing.  Here’s an essentially complete specimen for the echinoid collector who didn’t know you could find Paleocene echinoids in California. Nice to have one in your collection.