Found this while Walking in the tide pools at Pinnacle Gulch this morning.
We believe it's a vertabra and at first thought a flat fish but it's not flimsy like a vertabra would be for a flat fish. It's hard and this is the only piece we could find.
Looks like pittosporum ...
Multiple escaped specimens of P.Tobira. It’s a common landscaping plant with bird dispersed seeds, so escapes are to be expected.