Mussels And Barnacles
Probably California Mussels (Mytilus californiensis), growing in with Leaf Barnacle (Pollicipes polymerus). These two spieces usually have large homogenous colonies - so it looks like the Mussels are overgrowing the Barnacle colony.
Species: Mytilus californianus (California mussel), Pollicipes polymerus (Goose Barnacle or Goose Neck Barnacle)
John Harvey Photo > Botanical Beach > Mussels And Barnacles