Shell Beach is a beach in the Shark Bay region of Western Australia, 45 kilometres south-east of Denham. It covers a 110 km long stretch of coast along the L'Haridon Bight. It is one of only two beaches in the world made entirely from shells. The beach was named "Shell Beach" because of the great abundance of the shells of the cockle species Fragum erugatum. The seawater in the L'Haridon Bight has a high salinity due to both the geomorphology and local climate of the area. This high salinity has allowed the cockle to proliferate unchecked, since its natural predators have not adapted well to this environment. The shells typically reach a depth of 7 to 10 metres. Over time, the shells have formed a limestone that is known as Coquina. Before Shark Bay became a World Heritage Site, the limestone was mined and used for the construction of a number of buildings in the local town of Denham, Western Australia.