The general structure of the Himalaya is very regular: the first range of hills that rise above the plains of Hindostan is alluvial, north of which lies the Tariyani, a tract from 10 to 30 miles wide, 1000 feet above the sea, covered with dense pestilential jungle, and extending along the foot of the range. North of this region are rocky ridges 5000 or 6000 feet high. Between these and the higher ranges lie the peaceful and well-cultivated valleys of Nepaul, Bhotan, and Assam, of inexhaustible fertility, interspersed with picturesque and populous towns and villages. Though separated by mountain-groups, they form the principal terrace of the Himalaya between the Sutlej and Brahmapootra. Behind these are mountains from 10,000 to 12,000 feet high, flanked by magnificent forests; and, lastly, the snowy ranges rise in succession to the table-land. The principal and most elevated chains are cut by narrow, gloomy ravines and transverse dusky gorges, through which the torrents of melted snow rush to swell the rivers of Hindostan. The character of the valleys becomes softer in the lower regions, till at last the luxuriance of vegetation and beauty cannot be surpassed. Transverse valleys, however, are more frequent in the Hindoo Coosh than in the Himalaya, where they consist chiefly of such chasms filled with wreck as the tributaries of the Indus and Ganges have made in bursting through the chain. The mean height of the Himalaya is stupendous. Captain Gerard and his brother estimated that it could not be less than from 16,000 to 20,000 feet; but, from the average elevation of the passes over these mountains, Baron Humboldt thinks it must be under 15,700 feet. Colonel Sabine estimates it to be only 11,510 feet, though the peaks exceeding that elevation are not to be numbered, especially at the sources of the Sutlej; indeed, from that river to the Kalee, the chain exhibits an endless succession of the loftiest mountains on earth; forty of them surpass the height of Chimborazo, one of the highest of the Andes, and several reach the height of 25,000 feet at least. So rugged is this part of the magnificent chain, that the military parade at Sabathoo, half a mile long and a quarter of a mile broad, is said to be the only level ground between it and the Tartar frontier on the north, or the valley of Nepaul on the east. Towards the fruitful valleys of Nepaul and Bhotan the Himalaya is equally lofty, some of the mountains being 28,000 feet high; but it is narrower, and the descent to the plains excessively rapid, especially in the territory of Bhotan, where the dip from the table-land is more than 10,000 feet in ten miles. The valleys are crevices so deep and narrow, and the mountains that hang over them in menacing cliffs are so lofty, that these abysses are shrouded in perpetual gloom, except where the rays of a vertical sun penetrate their depths. From the steepness of the descent the rivers shoot down with the