Note centimeter scale bar. Quick metric scale conversion tip: One cm (centimeter) equals two-fifths inch. One mm (millimeter) equals one twenty-fifth of an inch. All from the middle Pleistocene Santa Barbara Formation, Santa Barbara, California.

Top to bottom: a pelecypod--Pododesmus macrochisma; middle--an operculum from a gastropod, Pomaulax gibberosa; a pelecypod--Saccella taphria. Photographs courtesy the Natural History Museum of Los Angeles County--from a publicly accessible site; I edited and processed them through photoshop.