The most northerly section of the African Rift Valley is inhabited by a pastoral people who call themselves 'Afar. Their present territory extends eastward from the scarp of the Ethiopian plateau and as far north and east as the Red Sea. The railway line between Addis Ababa and Jibuti appears to coincide with the southernmost fringes of 'Afar population. The area is mainly desert or semi-desert, and contains numerous tokens of its geological past in the form of volcanoes, lava fields, and hot springs. Survival is not easy in this harsh environment, so that to some extent most 'Afars are obliged to live a seasonally nomadic existence. Certain areas do have permanent habitations, but 'Afars have never taken seriously to agriculture and those who live in villages along the coast and engage in fishing probably exemplify the most radical departure from pastoralism. Most of the terrain described lies within Ethiopia, but there are a great many 'Afars in the contiguous Territoire Français des Afars et des Issas. As far as the 'Afar are concerned this political boundary does not underscore any tribal divisions of note and there is a good deal of contact between folk occupying areas on different sides of the border.