The African table-land, as a whole, may be described as a succession of extensive undulating plains (like the corrugations and so-called plains of Tibet, already mentioned), but dipping very gradually towards the west and north-west, and intetsected by numerous streams, which, after a short course over the surface of the plateau, fall abruptly into the deep-cut fissures or valleys just noticed, in which they soon reach a depression of 3000 to 4000 feet below the general level of the table land. In addition to the irregularities produced by these valleys, the uniformity of the surface is broken by loftier mountain-masses, which in some parts of Abyssinia attain an absolute elevation of from 11,000 to 15,00u feet. The eastern edge of the plateau itself has been clearly traced as far as the ninth parallel of north latitude, to which distance it forms the water-parting between the basins of the rivers Nile and Hawash. "How much further it extends southward," Dr. Beke remarks, "our present knowledge scarcely enables us absolutely to determine; but we may safely regard it as reaching beyond the equator." The snowy mountains observed by Captain Short, and those diacovered by the missionaries Krapf and Rebmann south of the equator, appear to be connected with the broad mountain range of eastern Africa, of which the Abyssinian table-land forms the northern portion. These are the "Mountains of the Moon" of the natives and of the ancient geographer Ptolemy, which Dr. Beke has proved to be thus a meridional and not an east and west chain, in which are the sources of the Nile, and which form the eastern face of the table land lu its southern extension. The continuation of this range was crossed as far south as 7° 30' south latitude by the recent travellers, Captaius Burton and Speke. Detailed information on the whole of this subject, with maps and sections of the country, will be found in Dr. Beke's work entitled ' The Sources of the Nile,' London, 1860; from which, except as otherwise indicated, and with alight variations of description, the preceding view of the African table-land has been derived.
Plains differ not only In their elevation, but in the horizontality of their surface and general slope, and in the nature of their soil ; which circumstances, together with theirgeograplilcal position, influence their climate and produetious, and give to the most considerable among them a particular character and physiognomy. It may be remarked that the rocky and sandy plains belong almost exclusively to the hot and temperate regions of the old world. The plains of America are generally characterised by their gramineous covering or their vast forests ; the Asiatic steppes by a twofold appearance, being in some parts studded with low saline plants, and in others, as iu southern Russia, Siberia, and Turkistan, covered with plants of the families of the Compositor and Leguminosts ; while the greater part of the European plains are richly cultivated.
We say such are the general characteristics, for there are plains of similar character and physiognomy In very different and widely separated regions of the world. The high land of the Campos Paresis, for instance, in South America, is very similar in physiognomy to the desert of Gobi In Asia. The Desiertas, near Coquimbo, are of the same character as the Sahara. The Punta of Hungary resemble the savannas of the New World; and the pampas of Cordova are not unlike some of the Siberian steppes.
Though, as we have said, plains constitute by far the greater portion of the earth's surface, and are very varied in their appearance, there are nevertheless some which are remarkable not only for their extent, but for the peculiarities which distinguish them • peculiarities derived, no doubt, in part, from the circumstances their original forma tion, and which no subsequent causes have been able to obliterate. These remarkable plains are known under the names of deserts, landes and heaths, steppes, savannas and prairies. llanos, pampas and selves (or forest plains) of the Marston DESERTS having been already described under their particular head, we shall here give a brief account of the others.
Maths aid Landes of Europe.—From Paris to Moscow and Caran on the one band, and to Astrakan on the other, is one continued plain, comprising the lowlands of Northern France, the Netherlands, the North of Germany, the whole of Prussia, and the greater part of Poland and Russia, as far as the first terraces of the Ural. Besides which there are many minor plains, as those of Wallachia and Bulgaria, Hungary, Lombardy, &c. The ancient civilisation of Europe has covered the greater part of its plains with cultivation and rendered some of these lands the richest in the world (the plains of Lombardy); nevertheless there are some spots which seem to defy all human efforts to bring them into cultivation ; such are those between the Lower Volga and the Ural, of which we shall speak more fully in describing the steppes, and such are the heaths and landes.' Of these, next to those of Russia, the most extensive are in Lapland and west Gothland. But the chief landes and heaths, properly so called, lie in the north west of Germany. In Lower Silesia, Lusatia, and Brandenburg, there is little else than sand, and also in Pomerania and Mecklenburg, studded with a few hills, numerous lakes, and, along the maritime parts of the latter, having some woods of oak. In Hanover the gentle acclivities are covered with heath, which extends through part of Holstein to the centre of Jutland. The most sterile parts of Hanover however are the landed of Luneburg and Verden between the Elbe and the Weser, and those of Meppcn on the right bank of the Ems. Those of Lfineburg and its vicinity are said to cover a space of about 6000 square miles. These landes are covered with heath, with pine woods, and marshes. On the west of the Ems, about Bentheim, there are also extensive landes covered with swamps and stagnant pools. In the of the Lower Rhine, in the environs. of Mensal°, between and Malmedy, we again find vast landes coated with heath. In France, of which country about one-twelfth is unproductive soil, there are extensive landes and barren spots. That tract which extends eastward from the right bank of the Adour, and gives its name to the department, consists almost wholly of pools, marshes, and heath, and this sterile plain extends a great way into the department of the Gironde. The shingle plain of Crau, in the department of the Benches du Rhone, is well known, and likewise the sterile chalky plain of La Champagne Pouilleuse. In the kingdom of Naples there are con siderable landes.