Part of Australia’s Great Dividing Range, the Peninsula Ridge, is like a backbone along the peninsula. This mountain range is made up of ancient (1,500 million year-old) Precambrian and Palaeozoic rocks. To the east and west of the Peninsula Ridge lie the Carpentaria and Laura Basins, themselves made up of ancient Mesozoic sediments. There are several important landforms on the peninsula: the large area of undisturbed sand dunes on the east coast around Shelburne Bay and Cape Bedford-Cape Flattery; the huge piles of black granite boulders at Black Mountain National Park and Cape Melville; and the limestone karsts around Palmerston in the south.