The sea-shore is generally low, except as influenced by Atlas, or the Abyssinian ranges, or the mountains of the southern extremity. There is, not uncommonly, a flat swampy plain, bordering on the sea, where the rivers push out their deltas, or form lagoons by their conflict with the fierce surge upon the shore. Generally at varying distances, there occur falls or rapids in the great rivers, showing that they are descending from interior plains of considerable elevation. The central regions seem, in fact, to form two, or perhaps three great elevated plateaux or terraced plains, having waters collected in their depressions, and joined by necks; such as are the prairies of Illinois, between the St. Lawrence and the Mississippi, or the llanos of South America between its great rivers. The southern one of these African plains approaches close to the Atlantic near the Orange River. Starting there at the height of three thousand feet, it proceeds round the sources of the river, and spreads centrally along by the lately visited, but long known lakes north of the tropic. The equinoctial portion of it is probably drained by the Zambeze and the Zaire, flowing in opposite directions. It appears to be continuous as a neck westward of Kilmandjaro, the probable source of the Nile; till it spreads out into the vast space extending from Cape Verde to Suez, including in it the Niger and the Nile, the great desert, and the collections of waters forming Lake Tzad, and such others as there may be towards Fitre. The mountains inclosing these spaces form a nearly continuous wall along the eastern side of Africa. The snows of Atlas form small streams, trickling down north and south; and, in the latter case, struggling almost in vain with the tropical heats, in short courses, towards the Desert of Sahara. There are found separate groups of mountains, forming for the continent a broken margin on the west. There may also be an important one situated centrally between Lake Tzad and the Congo; but there appears no probability of a transverse chain, stretching continuously across this region, as has hitherto had a place on maps, under the title of the “Mountains of the Moon.” No geological changes, except those due to the elevation of the oldest formations, appear to have taken place extensively in this continent. The shores of the Gulf of Guinea, and of the eastern regions, abound with gold, suggesting that their interior is not covered by modern rocks. The two extremities at Egypt and Cape of Good Hope, have been depressed to receive secondary and tertiary deposits. There may be other such instances; but the continent seems, during a time, even geologically long, to have formed a great compact mass of land, bearing the same relations as now to the rest of the world.