Cretaceous metamorphic rock, exposed principally on this one island
The rock the island is made of, and the reason geologists come here at all. The Catalina Schist is a metamorphic complex formed during the Cretaceous and exposed principally on this island, which is an unusually convenient place to look at rock that spent its early life being crushed and cooked well below the surface. If you only ever pick up one stone on Catalina, this is what it will be.
Santa Catalina Island, California
See it on the map
Other places on the map within a couple of hours of here.
