Shell Beach, in Western Australia’s Shark Bay, has a unique composition, consisting almost entirely of the white shells of Fragum erugatum, a species of cockle (a bivalve). The beach lies in a partially enclosed area of Shark Bay known as L’Haridon Bight. This cockle thrives here because its predators cannot cope with the high salinity of the seawater. On the foreshore of Shell Beach, the layer of shells reaches a depth of 26–30 ft (8–9 m) and also forms the sea floor, stretching for hundreds of yards from the shoreline. On the upper parts of the beach, away from the water line, many of the shells have become cemented together, in some areas leading to the formation of large, solid conglomerations. These are mined to make decorative wall blocks.