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portion to other matters as well worthy of investigation, but they have come into their true place, and now only wait the development of new facts regarding the size and height of some, to be properly understood and appreciated.

The measurements made in North, Central, and South America give the following results; much more complete, it may be remarked, than the results yet gained in Asia and Africa.

To the plateaus of the first class belong in America, at latitude 0°, the plain of Quito, almost 9000 feet above the sea, (Los Pastos in the north being near 11,000 feet,) and to the south, at 17° south latitude, the plateau of Upper Peru. Here the great Lake Yiticaca is found, 12,000 feet above the sea; eastward of the lake, the table-land rises yet higher, and at Alto de Toleda it is 14,000 feet in elevation, as high as the highest part of Thibet. At 20° south latitude, south of Lake Yiticaca, is the City of Potosi, whose streets are 12,822 feet above the Pacific.

In Central America is found, at 20° north latitude, the extended table-land of Mexico, 500 miles wide, rising to a height of 7000 feet, and farther to the north, in New Mexico, the plateau of Santa Fé, 35° north latitude east of the Rocky Mountains, and 7100 feet above the sea. The table-land on the west side of the mountains, and toward the Great Salt Lake, is undoubtedly just as elevated.

Europe and Australia are wanting in plateaus of the first rank, and in general the whole immense flat northern districts of the globe, though we are not yet quite familiar enough with the extreme north of America to speak with entire confidence regarding it.

Plateaus of the Second Class.

Elevated plains which are at once continuous and bounded by a definite line of demarkation, and which do not attain an altitude of more than 4000 or 5000 feet, are considered plateaus of the second class. They are far more general over the whole earth than plateaus of the first class; in every one of the great divisions of the globe they appear in the utmost possible diversities of elevation, sometimes so gradually ascending that the lowest limit is hardly to be perceived. This makes it not only expedient but necessary to assign to plateaus a fixed though arbitrary system of classification, for without it we could attain to no thorough view of all their relations. This general system must afterward be confirmed and justified by protracted special investigations.

That not all the vast plains of Central Asia, from Thibet to the Altai Mountains, and from the Belur range to the Chinese Gobi, belong to the first class of plateaus, has been demonstrated by the Russian measurements, made by Fuss and Bunge in 1832, between Lake Baikal, Kiakhta, and Peking, and rendered highly probable by the investigations of Klaproth, Humboldt, and Zimmermann. Toward the northwest the plateaus generally sink from the moderate elevation of the Middle Gobi, 4000 feet, to Lake Baikal, 1332 feet above the sea, Lake Zaison, not 1000 feet above the sea, and the border of the plateau at Choimailocha, the Chinese frontier post on the Siberian line, 1000 feet above the sea, then to the lower border of the plateau of Bookhtarminsk (936 feet) and Semipalatinsk on the Irtish, (708 feet,) where the great Siberian plain begins. In the valley of the Tarim and of Lake Lop, pomegranates and grapes thrive, and cotton, which has

been raised of an excellent quality in Eelee, is found at a height of from 1200 to 2000 feet. And in contrast with the great arctic plain of Northern Asia, not 500 feet above the level of the sea, this central plateau will take its place as distinctively of the second rank.

The plateau of Persia lies on the border of both classes; for while the central portion touches 4000 feet, some parts rise much higher and some sink much deeper than the normal point. These balance each other, and the average is about the maximum elevation of plateaus of the second degree.

East of the Persian plateau lies the plateau of Cabool, 6000 feet above the sea. On the northern edge of Afghanistan is the plateau of Bamain, 7500 feet in elevation. More to the south is the high plain of Candahar, being 3500 feet, and the City of Candahar, 3264 feet above the sea. The plateau of Kweltah west of the Bolan Pass is 5220 feet. Still farther to the south is the great plain of Beloochistan, 7000 feet, with the City of Kelat, 5418 feet above the sea.

In the central part of the eastern Persian plateau in ancient Gedrosia, Drangiana, and Parthia, and Lake Zareh, the depression is the lowest. At Lake Zareh the elevation is 2100 feet; at Herat, more to the north, 2628 feet. In West Persia, on the meridian of the Caspian Sea, it rises higher; on the northern edge at Teheran it is 3672 feet; at Schabred, southeast of Astrabad, it is 4000 feet; at Kasbin, west of Teheran, it is 4000 feet; and at Samegon, 5700 feet. The lowest depression at Com and

Kashan is not 2000 feet above the sea. Toward the northwest Persia thrusts up a short arm into the adjoining territory of Armenia. This is the highland of Ayerbaijan, Zoroaster's "Land of Fire." This connecting plateau of

7000 feet elevation belongs to the first class. To the west of this the plateau of Armenia extends in varying range of elevation, from that of Lake Van, 5124 feet, to the plain of the Aras, (the ancient Araxes,) on which the double cone of Ararat rises to a height of 14,656 feet. But the table-land at the northern base of Ararat, the site of Erdschmiazin, is only 2860 feet high, Erivan a little higher, and Erdzeroune, on the plateau of the Taurus, the plain of the Upper Euphrates, 5730 feet.

The plateaus of Asia Minor embrace wide plains extending through the whole of the country, at an elevation toward the east, in ancient Lycaonia and Cappadocia, of 3000 feet, and sinking toward the west to 2000 feet.

To the plateaus of Armenia and Lycaonia, Strabo, whose home was there, and who carefully studied them, gave the expressive name of opoñédta, i.e. mountain plains, a term which corresponds remarkably with our word plateau, but which, as Humboldt has remarked, was not of much use among the ancients. Strabo, however, directed attention also to the Oropedia of Sicily and India

In India, Deccan displays similar formations, which rise gradually from south to north in Mysore, in Poonah of the Mahrattas, and in the table-land of Vindhya and Malwah, to 2000, 3000, and even 4000 feet. Deccan enjoys an admirable climate and the richest abundance of all natural productions. China too must have plateaus, for the Chinese word youen indicates very clearly a large elevated plain.

In Arabia the plateaus of the second class are largely found, and their height ascends from north to south, instead of from south to north as in Deccan. The Syrian Hauran is 2000 feet high, the plateau of Damascus 2200 feet, the plateau of Taif, above Mecca, 3000 feet, the plateau of Sapaa, in Southern Arabia, 4000 feet.

In North Africa that portion of the great Sahara which has heretofore been considered a low plain, lying between Tripoli and Lake Tchad, has been ascertained by the German explorers, Overweg and Vogel, to be a table-land of the second class, ranging in elevation from 1000 to 2000 feet. It begins at the Chorean plateau (2000 feet) in the south of Tripoli, and sinks to an elevation of 800 feet in the neighborhood of Lake Tchad. The average altitude is about 1500 feet. This moderate elevation of Sahara corresponds with the equally high plateau of Cyrenaica, 2000 feet.

The Atlas plateau, in the northwest of Africa, rises to a greater height-2000 to 3000 feet; the upper course of the Draa, near the Sahara, being 3000 feet; the high, broad table-land on which Timbuctoo lies, according to Renon's measurement, is 1500 to 1800 feet above the sea.

In south Africa the low, or rather the moderate plateau, which borders the district of the Bechuanas on the north, rises, as it advances toward the lower rim of Africa, at Cape Colony, to an altitude of 3000 feet.

America has many plateaus of the second range of elevation, but her highlands of the first class are so imposing in extent, as well as in elevation, that they have been more carefully observed than the table-lands of the second class.

Along the eastern slope of the Andes, on the same parallel with the great plains of the Orinoco, the Amazon, and the La Plata, these plateaus extend, touching the base of the mountains, and appearing rather as terraces, or vast plains of transition, from the highlands to the lowlands, than as independent forms. Where Alexander von Humboldt measured them, west of the low plains of the Amazon, he found their height, measured from the

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