Rock and mountain types, artwork. The types shown range from desert sandstones to volcanic peaks. At bottom is Uluru (Ayers Rock, 348 metres), an inselberg of arkosic sandstone in Australia's Northern Territory. At lower left is the Devil's Tower (386 metres), an igneous intrusion (laccolith) in the Black Hills, Wyoming, USA. Behind these are over 1000 metres of strata of the Grand Canyon, Arizona, USA, eroded over millions of years by the Colorado River (far right). At right, the stratovolcano Mount St Helens (2550 metres), Washington State, USA, after its 1980 eruption. Behind this is the stratovolcano Mount Fuji (3776 metres), near Tokyo, Japan.