CHAPTER V.
FEATURES, ANCIENT AND MODERN.
The fifth division of Africa borders on the Red Sea. It includes the countries of Abyssinia, Nubia, and Egypt.
Between Abyssinia and the Mediterranean Sea is the low valley of the Nile. This is separated from the Red Sea on the east by a bold, mountainous region. A low ridge of limestone and sandstone hills separates it from the Libyan Desert on the west.
Abyssinia, or Habesh, as the Arabs call it, is a large highland tract in East Africa. It rises from the Red Sea, in a series of terraces, towards the southwest.
Between the highlands of Abyssinia and the Red Sea, lies a flat tract of country called Adal. This tract is very narrow at its northern extremity, but gradually widens towards its southern extremity.
The plains of Nubia and Kordofan form the northern and western boundaries of Abyssinia. There is comparatively little known of its southern boundaries.
The general characteristics of the country are high table-lands, intersected by deep ravines and steep terraces of sandstone.
These ravines have been formed by the action of the rivers upon the rocks. Sandstone, being a comparatively soft rock, would, in the course of ages, be gradually worn away as the waters flowed over it. No doubt the terraces have been formed from the exposure of these rocks to the elements for countless ages.