A badlands (also badland) is a type of arid terrain where softer sedimentary rocks and clay-rich soils have been extensively eroded by wind and water. It can resemble malpaís, a terrain of volcanic rocks. Canyons, ravines, gullies, hoodoos and other such geological forms are common in badlands. They are often difficult to navigate by foot. Badlands often have a spectacular colour display that alternates from dark black/blue coal stria to bright clays to red scoria.