Close-up of a Dusky Turban Snail shell (Tegula pulligo). This shell is not entire; it has a broken spire (otherwise it would be higher!). ;)
It was washed ashore on Bodega Head and photographed 23 March 2016.
P.S. This is one of three species of turban snails on Bodega Head. The others include Black Turban Snail (Tegula funebralis) and Brown Turban Snail (Tegula brunnea).