880 



ASIA. 



than any of the other quarters of the world, Africa not excepted, yet all the facts that bear on 

 the subject concur in proving, that the notions prevalent respecting its general elevation have 

 been greatly exaggerated. A large portion of the interior of the continent, however, still re- 

 mains unexplored by European travelers ; and even in regard to those parts where it is easy of 

 access, there is a great want of good barometrical observations. On the northern side of the Altai 

 range, and indeed over the whole northern extremity of Europe and Asia, the elevation of the 

 ground is very inconsiderable. From the plains of Brabant one may pass, from west to east, 

 to the steppes which border the western declivity of the Altai and Chinese Zoungaria, — from 

 the Scheldt to the lenisei, — over 80 degrees of longitude, without meeting with a single ele- 

 vation exceeding 1,200 or 1,300 feet. Of late years a great number of barometrical measure- 

 ments have been made on the frontiers of Chinese Zoungaria, the banks of the upper Irtyche, 

 and the plains bordering on lake Dzaisang, in countries situated on the southern side of the 

 Altai range. The mean of these observations gives to this district, and to a great part of the 

 immense steppe of Kirghiz, an elevation scarcely exceeding 1,300 or 1,600 feet above the 

 level of the sea, and consequently not greater than that of the lake of Constance or the city 

 of Munich. Of the countries lying to the south of the Kuen-lun, we have a very imperfect 

 knowledge ; but the platform of Persia, which extends from Teheran to Shyraz, and from 

 which the two great chains of the Kuen-lun and Himalaya proceed, is estimated by Fraser to 

 have a mean elevation of about 3,500 feet. In the immense longitudinal valleys which sepa- 

 rate the principal mountain chains, there are extensive tracts of country which are considerably 

 depressed below the general level of the plains. It is worthy of remark, that the countries 

 situated between the Kuen-lun and Thian-chan have a general inclination from west to east, oc- 

 casioned, apparently, by the upraising of tlie great transverse chain of the Bolor ; while the 

 valley of Zoungaria, between the Thian-chan and the Altai, is inclined to the west, the trans- 

 verse ridge in this case being situated at the eastern extremity of the valley. 



From a comparison of all the observations we possess on the configuration and elevation of 

 the Asiatic continent, it results, thai the central region, between the parallels of 30° and 50°, 

 and between the meridians of the Beloor and lake Baikal, contains a vast extent of country o^ 

 which the elevation probably does not exceed that of the plains of Bavaria, Spain, and the 

 Mysore. There is every reason to suppose, that plains of the same elevation as those of 

 Quito and Titicaca occur only, if they occur at all, in the bifurcation formed by the junction 

 of the Himalaya and Kuen-lun, in the group of mountains surrounding lake Khoukhounor, and 

 in Gobi to the northwest of the Thian-chan. 



4. Depressions below the Surface of the Sea. The most singular feature in the form of 

 the Asiatic continent, and one of the most remarkable on the surface of our globe, is the 

 depression of a very considerable portion of the northwest of it below the level of the sea. 

 Between the Kouma, the Don, the Wolga, the lak, the Obtchey-syrt, Lake Aksal, and the 

 Lower Sihoun, and along the A moo, the whole country, including a space exceeding 375,000 

 square miles, is depressed below the general level of the surface of the earth, and forms, as it 

 were, an immense basin, the lowest part of which is occupied by the Caspian Sea and Lake 

 Aral. The surface of the Caspian is 320 feet below the level of the Black Sea, and that of 

 Lake Aral 203 feet. 



5. Volcanoes. The traces of volcanic action in Central Asia extend over a very large 

 portion of the interior of the continent, embracing almost the whole of Chinese Tartary, 

 and, on account of the peculiarities of their position, offer to the geologist a subject of very 

 interesting speculation. The principal seat of volcanic action in the interior of Asia is in the 

 second range of mountains, or the Thian-chan, the whole northern declivity of which presents 

 volcanic phenomena. The most remarkable volcano in this chain is the mountain called in 

 Turki Echikbach, and in Chinese Pe-chan, or White mountain, an appellation which may be 

 derived either from the circumstance of its rising to the region of perpetual snow, or because 

 its surface presents a whitish appearance, from its being covered with muriatic efflorescences. 

 According to the reports of the Chinese, it vomits forth fire and smoke without intermission. 

 On account of its central position, and great distance from the sea, this volcano is an object 

 of peculiar interest to the geologist. It is situated a little to the east of Aksou, the longitude 

 of which, as determined by the missionaries, is 79° east longitude. Its distance from the Cas- 

 pian sea is about 1,400 English miles. The Caspian Sea appears to be surrounded by a vol- 

 canic territory. On the eastern side hot springs burst forth at Soussac, in the Karatau moun- 



