The same philosopher has observed, that the Cordil leras of the Andes, though they extend from north to south 120 degrees of latitude, are not more, ge oerally speaking, than from two to three, and very rarely from four to five degrees in breadth ; but the vast surface of table-land, supported by the great Himalaya buttress, stretching from Daouria on the east, to Belur-tagh on the west, through 47 degrees of longitude, and from the Altai on the north, to the Himalaya on the south, through a mean breadth of 20 degrees of latitude, presents a plateau, more or less elevated, equal to above three millions of square miles.
In confirmation of the great influence of radiated heat from extensive elevated plains, we have now some strong facts both in America and Asia. Thus, on the mountains which rise out of the elevated plain of Mexico, Humboldt observed the lower line of per petual congelation in lat. 19°-20° at 15,090 feet above the sea, which, by the table of Professor Les lie, ought to have been at 13,560, making a differ ence between fact and theory of 1530 feet. The lower point on the side of Chimboraco, nearly un der the equator, was 15,746 feet, being only 656 feet higher than on the mountains of Mexico ; whereas, by Leslie's table, the difference ought to be 1729 feet. Compare, again, the height of this lower limit of perpetual congelation on the side of Chimbo raco with the observations of Captain Webb in the Nitee Pass, and we have the extraordinary anomaly of a place in Asia, in 30° of latitude, having that li mit higher by 1253 feet than another place in Ame rica immediately under the Equinoctial Line ; and at 5500 feet, or more than a mile, higher than it ought to be in that parallel of latitude, according to the theory on which Professor Leslie constructed his table. • It is right to observe, however, that the same ano maly exists, though in a less degree, on the southern face and abutments of the Himalaya range. Thus the elevation of Kedar-nath, at 12,000 feet, is below the verge of perpetual snow, which in Europe, on the same parallel of latitude, would be at 700 feet lower. Thus, also, the village and temple of Milem, in lat. 25' were not only without snow at the height of 11,790 feet, but extensive fields of buck wheat and Tartaric barley were growing at that ele vation. In the same degree of latitude the same height in Europe would be some hundred feet with in the limits of perpetual snow. At the same height,
on the 21st June, Captain Webb's encampment was surrounded with flourishing woods of oaks, of the long-leafed pine, and the arborescent rhododendron, and the surface was clothed with a rank vegetation. On the following day he determined the elevation of Pdgointi-churhai pass to be more than 12,700 feet above the sea; yet here even no snow was visible, but the black soil was clad with creeping plants ; and the shoulder of a mountain rising still higher was without a vestige of snow, and appeared, as far as could be seen through the mist, enamelled with flowers. The reflected heat from the perpendicular face of the immense mass of naked rock, .on which snow cannot rest, exposed to the rays of a western •sun, will probably be deemed sufficient to ex the anomaly which is found to exist on the southern side of the chain.
Of the geological strata of these mountains we have yet but little information. Mr Baillie Frazer, who penetrated to the very base of the great chain, at the head of the Jumna and the Bhagarathe branch es, describes the first and inferior hills of sand stone, more or less destructible, of indurated clay with beds of rounded pebbles and gravel. The se cond ridge of hills, rising to the height of 1500 to 5000 feet, are sharp, rough, and run into numerous ridges, divided by deep shaggy dells ; and the crests of the ridges are frequently so sharp that two per sons can hardly stand abreast upon them. Beyond these are a mass of hills entirely composed of lime stone, of a round, lumpish, rugged character, whose highest points may be from 5000 to 7000 feet. Next to these commences the schistus, or slate, which con tinues to the very roots of the snowy mountains. All above appeared to be a striated hard grey gneiss, and a compact granite, which, Mr Fraser supposes, is the material which constitutes the highest ridges and crests of this great mountain range ; but schis tus is the rock• that mostly predominates. Hot springs are found on both sides of the Himalaya, and copper, lead, and iron, are commonly met with. Gold is also found in the beds of the rivers. Captain Webb obtained the petrified bones of an animal of the deer kind, which were dug out of a bed of gra vel, on the side of the Caillas mountain, at least 16,000 feet above the level of the sea, a height at which, it may safely be asserted, no other organic remains have hitherto been discovered. (K.)