314 Dr T. Thomson on the Climate and 



part of the Indian plain, but may more properly be considered as 

 wide mountain valleys, and they in fact closely resemble in vegeta- 

 tion the valleys of the larger Himalayan rivers in the east part of 

 the chain. 



Close to the foot of the chain of mountains throughout its whole 

 course from east to west, there lies a belt of forest and swampy land, 

 which is well known in India by the name of Xerai, and which, 

 where it is developed to any considerable extent, bears a very bad 

 character for unhealthiness, and is indeed in many places quite im- 

 passable for Europeans at most seasons of the year. This forest belt 

 seems to be due to the greater humidity of atmosphere, and at the 

 same time greater equability of temperature, which is produced by 

 the proximity of the mountains. Its width is very various, from 

 forty to fifty miles, to which I believe it attains in some parts of 

 Nepal, to eight or ten miles, which is a more common width. West- 

 ward of the Jumna it almost disappears, being represented by a line 

 of swampy or marshy ground, and a low jungle of bushes of the com- 

 mon plain species of trees. 



In this belt, which occupies the base of the mountains, the vege- 

 tation is of course quite tropical in character, and is too varied to be 

 described in detail. Large cotton trees (^Bomhax) are in all parts of 

 it particularly conspicuous from the immense size of their trunks, 

 which are not cylindrical, but buttressed all round by immense plates 

 which project far forward from the main trunk. Numerous fig-trees 

 of very various species are also common, especially to the eastward, 

 where many fine forms of these magnificent trees everywhere meet 

 the eye, along with species of Dillenia, Gareya^ Bauhinia, and La- 

 ^erstromia. 



It is from the forest which lies along the foot of the Himalaya 

 that a great part of the timber is derived which is consumed in 

 northern India. In the most eastern part, the most valuable timber 

 is furnished by Lagerstromia regina^ and perhaps other allied 

 species ; further west, the sal Patica robusta, the Shorea robusta of 

 Roxburgh, is that which is most esteemed. The sal extends from 

 the valley of Assam as far west I believe as the Punjab, and is found 

 not only in the forest tract, but also in hot valleys among the moun- 

 tains. It belongs to a natural order (DipterocarpecB) which is pecu- 

 liarly Indian, and which furnishes many valuable kinds of timber. 

 None of the species, however, except the one under consideration, 

 extend beyond the tropics ; but they abound in the hilly countries 

 of the peninsula as well as in the low ranges of the Malayan penin- 

 sula, and I believe in Java and other Indian islands. The sal is so 

 much valued that it has become, in accessible places from whence it 

 can easily be conveyed to the plains, very scarce, and in the vicinity 

 of large towns where there is a great demand for timber, I believe 

 almost extinct. It is therefore less commonly employed than the 

 sissoo, a species of DalbergiOf which is particularly abundant along 



