Abalone sea shells resemble a valve of a large clam, except for the spiral whorl.  They are usually attached to rocks by a large muscular foot.  Sea water is drawn in under the edges of the shell; it passes over the gills, and leaves through the natural holes.  The foot is edible and highly esteemed.  These shells are often used for jewelry, buttons and inlays.  Found on or beneath rocks, mostly in shallow water.