Clams differ in looks from cockles as the ridges on a cockle shell run to the hinge, where clam shell ridges run across the shell. Clams prefer sandier sediment than cockles. A tasty morsel, clam chowder is a great dish to try if you are new to them, simply steaming with Asian flavours such as lemongrass and ginger or pan frying until they open and lightly frying the meat in a little butter.