In 1940 the Fish & Game Dept. identified 3 types of clams, bivalves, living around Halfmoon Bay: the Pismo, Rock Cockle and the Boring.
Meet the “Pismo”:
Meet the “Rock Cockle”
And then there’s the “Boring” Clam. There are two kinds of Rock Boring clams, both very similiar.
(1) Anterior end of valves roughened and round, siphonal end terminates in soft scales. Shell can be completely closed. Hinge protected by two long slender plates. Siphons completely retractile. Reaches a length of 3 inches. Found Coos Bay to San Diego.
(2) Appearance much the same as the preceding species. Siphonal end of valves covered with brownish scales. Hinge plates short and triangular. Grows to a length of 3 inches. Found Alaska to Mexico.