Much of the Western Plateau has existed as a landmass for more than 500 million years and is made up of individual plateaus, including the Kimberley, Hamersley, and Yilgarn. These plateaus in part comprise cratons such as the Yilgarn Craton and the Pilbara Craton. In contrast, the Nullarbor Plain is an uplifted sea floor, a limestone plain of Miocene age. The rocks along a coastal strip around the Western Australian capital of Perth are much younger than the adjacent Yilgarn Craton and are separated from it by the Darling Fault escarpment.