‘My kids they thought they were collecting seashells ... Pismo clams have both shells intact together, explained Gil. ‘If you have a dead sand dollar, a dead animal, or something like that ...

These crustaceans have been misnamed for two reasons: First, they’re not true crabs, like blue crabs, in that they don’t have a uniformly hard exoskeleton and can’t grow their own shells.

Some ammonites had long, straight shells, while others had helix-shaped shells. Most species, however, had coiled shells lined with progressively larger chambers separated by thin walls called septa.