The valleys and precipices of South Africa have been shaped by the mighty currents which circulate round the promontory of the Cape; and the flat summit of Table Mountain, at the height of three thousand six hundred feet, is a rocky reef, worn and fretted into strange projections by the surge, which the southeasters brought against it, when it was at the level of the sea. The present state of organized life in Africa tells the same tale. It indicates a land never connected with polar regions, nor subjected to great variations of temperature. Our continent, America, is a land of extremes of temperature. Corresponding to that condition, it is a land characterized by plants, the leaves of which ripen and fall, so that vegetation has a pause, waiting for the breath of spring. All the plants of southern Africa are evergreens. The large browsing animals, such as the elephant and rhinoceros, which cannot stoop to gather grass, find continuous subsistence in the continuous foliage of shrubs. America abounds with stags or deer--animals having deciduous horns or antlers. Southern Africa has none, but is rich in species of antelopes, which have true or permanent horns, and which nowhere sustain great variations of heat and cold. Its fossil plants correspond apparently in character to those which the country now bears. Its fossil zoology offers very peculiar and interesting provinces of ancient life. These have been in positions not greatly unconformable to those of similar phenomena even now. Great inland fresh-water seas have abounded with new and strange types of organization, in character and office analogous to the amphibious forms occurring with profusion in similar localities of the present interior. These, and representatives of the secondary formations, rest chiefly on the old Silurian and Devonian series, the upheaving of which seems to have given the continent its place and outline. Coal is found at Natal, near the Mozambique Channel, but not hitherto known to be of value. Africa still offers, and will long continue to offer, the most promising field of botanical discovery. Much novelty certainly remains to be elicited there, but it is very dilatory in finding its way abroad. Natal is the region most likely to be sedulously explored for some time. Vegetable ivory has been brought thence, and elastic, hard, useful timber abounds. Much lumber of good and varied character is taken to Europe from the western regions of the continent; but so greatly has scientific inquiry been repelled by the deadly climate, that even the species affording it are unknown, or doubtfully guessed at.