Littlenecks and Manilas
Manila and native littleneck clams are very similar in appearance and can reach three or four inches in length.  The shells of both species have concentric rings and radiating ridges.  Manila clams have oblong shells with a faint, variable geometric pattern outside and a purple stain inside.  The native littleneck clam has a round, chalky-white shell.

Butter
Butter clams grow to be six inches long and have chalky-white shells with only the concentric rings.

Horse
Horse clams can reach eight inches in shell length.  The shell is chalky-white with yellow-brown patches of skin-like perostracum and is flared around the neck.  The neck, which cannot be withdrawn into the shell, is tipped with a leather-like flap.

Softshell Clams
Softshell clams can become six inches long.  They have chalky-white shells which are rounded at the foot and pointed at the neck.  These tasty clams are usually buried 8 to 14 inches in mud and sand bottoms near the mouths of rivers.  Softshell clams are harvested with long-tines rakes.

Cockles
Cockles are easily recognized by their light brown color and their prominent, evenly spaced ridges which fan out from the hinge area to the shell margin.  Cockles are found near the surface of sand-gravel beaches throughout the Puget Sound.  You can gather them by hand or with a garden rake.

Scallops
Three species of scallops are found in local waters – the small pink, which grows to around 2.5 inches, the large weathervane scallop which may reach nine inches, and the heavy-shelled rock scallop which can also reach nine inches.  The latter is often covered by tubeworms, barnacles, and other organisms.  Scallops are found subtidally throughout the Puget Sound, and the Strait of Juan de Fuca.  They are usually taken by commercial divers.  The sport harvest of scallops is usually not allowed.

Oysters
Oysters have irregular, chalky-white shells that are often distorted to conform to the shape of the object to which the oyster is attached.  Oysters are often found in groups attached to one another or a common object such as a rock or shell.  Most recreational oyster harvest occurs in Hood Canal.  All oysters in Clallam County are farmed, and most are privately owned by commercial operations.  Spawning during the summer reduces the quality of the oysters for eating.

Mussels
Mussels have oblong, blue-black shells and are usually found in dense mats attached to solid objects by their many strong fibers called byssal threads.  The blue bay mussel of Puget Sound grows to about three inches while the California mussel, which is found on the open coast, can grow to over six inches.  It is illegal to harvest mussels from Salt Creek Park.

Geoducks
The geoduck is the world's largest burrowing clam and can weight as much as ten pounds.  The geoduck's large neck lacks the leather-like flap of the horse clam.  Geoducks live buried two to three feet deep in the sand or mud.  They are rare on intertidal beaches but can be dug on extremely low tides.