Vegetation of the Himalaya. 315 



the foot of the mountains, more especially to the westward, growing 

 in great profusion on gravelly soil, and yielding a most ornamental 

 and valuable wood. 



The forest belt which skirts the base of the mountains rests for 

 the most part upon a dry gravelly soil, which slopes somewhat rapidly, 

 though not perceptibly to the eye, toward the open plains, and is 

 generally dry. Just outside the forest, or sometimes still interspei-sed 

 with patches of wooded ground, there is generally a low swampy 

 tract, which is lower than the country immediately beyond, and from 

 which the water drains away slowly and with difficulty. This is the 

 Terai par excellence.^ and is, from the constant dampness of the soil, 

 and the dense heat of the summer, peculiarly unhealthy. It is too 

 low and too unhealthy to be much cultivated, and is generally covered 

 by a dense jungle of tall grasses, species principally of Saccharum^ 

 Arundo, AndropogoUy and Anthistiria, which rise high enough to 

 cover an elephant, and afford shelter during the greater part of the 

 year for multitudes of tigers and other wild animals ; at the com- 

 mencement of the cold weather, this long grass is set on fire and 

 burnt down by the inhabitants of the hills, who at that season de- 

 scend to the level country to feed their cattle and flocks. It is again 

 abandoned to itself at the commencement of the hot season, as soon 

 as grassy vegetation has made sufficient progress in the mountains. 

 These swampy tracts are a series of lateral valleys which run parallel 

 to the base of the mountains, and which, from being very slightly in- 

 clined, present great obstacles to the escape of the water discharged 

 into them by numerous streams from the mountains. 



Along many parts of the Himalaya, a similar series of valleys 

 nearly parallel to the axis of the chain, but bounded externally by 

 hills of from 2000 to 4000 feet in elevation, may be observed. These 

 valleys are known in the western Himalaya by the name of Dh(ins. 

 One of the largest of them is the Deyra Dhun, well known to 

 Indian travellers as being traversed en route to Masuri, a favourite 

 hill station, and now celebrated as the seat of an extensive cultiva- 

 tion of tea in a climate which seems to suit admirably that valuable 

 plant. The Deyra Dhun is in its centre or highest part, from which 

 it slopes down both to east and west towards the Ganges and Jumna, 

 about 2500 feet above the level of the sea, or 1500 feet above the 

 level of the plains, immediately outside of its bounding range. 



Other Dhiins occur all along the hills to the westward. They are 

 bounded on the north by the ancient rocks of the Himalaya, but on 

 their outer side always by the tertiary sandstones and conglomerates, 

 now so well known from the labours of Falconer and Cautley, as the 

 Sewalik formation. In the north of the Punjab there are often sevei-al 

 series of these valleys, the innermost only resting on transition rocks, 

 the others excavated out of the tertiary sandstones, which have there 

 often a width of from 30 to 50 miles. 



The vegetation of the low mnges of hills by which the Dhiins are 



