These are common on all limestone rocks in the area. Night low tide on the city dock (-5 ft), on limstone riprap.
At the end of Dock H at the Woodley island marina, Humboldt Bay, with Mytilus, sponges, tunicates, eelgrass, etc.
I have a shell that broke, that is exactly like this one except a red-pinking color. Shape is interesting for a bivalve.
Single shell found lodged under Hormosira
@invertzoo I thought you might know what this is. about 30 million years old. I also put 4 more observations of different fossil shells all under bivalves. Just hoping you would know what they are.
Small specimen of a little known brachiopod found mainly in S. CA but also described as far north as Tomales Bay. It has turned up in a few recent surveys in Elkhorn Slough. ID and info from John Pearse and Mark Silberstein.
Los braquiópodos (Brachiopoda, del griego brakhýs, "corto" y podós, "pie") son un filo de animales marinos pertenecientes al clado de los lofoforados. Aunque se han descrito más de 12.000 especies fósiles, sólo existen unas 300 especies actuales. Aparecen en el registro fósil desde el Cámbrico inferior.