Escarpment

After the canyons, the most remarkable features of the country are the long lines of cliffs. These are bold escarpments scores or hundreds of miles in length,—great geographic steps, often hundreds or thousands of feet in altitude, presenting steep faces of rock, often vertical.

Source: wiktionary

The railway winds down the face of the escarpment on a steady grade of 1.05 per cent, which is considerably better than the old route, up which trains took 2 hr. to struggle 15 miles, with two stops.

Source: wiktionary

One of [the] defining characteristics of [the northern Horn of Africa] is its separateness, and this is partly due to its physical diversity. A detailed description of physical geography falls outside the scope of this book. It may simply be noted that the region comprises highlands that are bounded on the east by the precipitous escarpment bordering the Danakil lowlands and the Red Sea. To the west, the country descends more gradually to the extensive plains of the Nile Valley but is riven by the rugged valleys of the Takezze and other Nile tributaries. In the north, with decreasing altitude, the terrain becomes progressively more arid as the Sudanese lowlands converge with the Red-Sea coast. It is only to the south that the highlands continue, linking them with the principal mass of the Ethiopian plateau, near the western edge of which lies Lake Tana and the source of the Blue Nile.

Source: wiktionary