Topographically uniform, the Namib Desert consists of vast plains of low altitude, stretching from the coast some 60 to 120 km inland. Further inland, the desert is often fringed by a steep escarpment, leading up to a plateau attaining altitudes of 1000 to 1800 m. The desert is geologically characterized by very old rock formations and a predominance of erosional processes since the Cretaceous. These processes shaped the wide plains, tilted towards the Atlantic Ocean.