(> MALLET : GEOLOGY OF DARJILING AND WESTERN DUARS. 



Tursa belong 1 to the south-eastern spur, while those between the Tursa 

 and the Raidak form the termination of a great ridge running southward 

 from Chumalari (23,944 ft.) and dividing the basins of those rivers 

 from each other. 



At Phallut, near the head of the Ramman river, where the boun- 

 daries of Nepal, Sikkim, and Darjiling meet, the Singalela ridge has an 

 elevation of 12,042 feet, this being the culminating point of the district. 

 The highest eminences are nearly all situated along the continuation of 

 the main ridge, like Tanglu (10,080), Senchal (8,606), and Mahaldaram 

 (6,000). Similarly, the highest point of the Daling hills is where the 

 main ridge first enters British territory, where it has an altitude of over 

 10,000 feet ; the other principal elevations do not exceed 7,000 or 8,000. 



The densely luxuriant vegetation by which these mountains are 

 covered, ranging from the matted cane-brakes of the Terai, and the 

 Indian rubber trees and other tropical forms of the deep valleys, to 

 the oak and pine forests which clothe the highest ridges, has been 

 described by Dr. Hooker in his journals. He attributes the heavy 

 rainfall to which such luxuriance is largely due to the fact that the 

 alluvial plain between Sikkim and the mouths of the Ganges is almost 

 a dead level, the foot of the hills being only 300 feet above the sea. 

 Hence the vapour-laden southerly winds from the Bay of Bengal reach 

 the outer range of hills without impediment, while the same current, 

 when deflected easterly to Bhutan or westerly to Nepal and the north- 

 west Himalayas, is intercepted and drained of much moisture by the 

 Khasia and Garro hills in the former case, and the hills of Rajmahal 

 and Chutia Nagpur in the latter. Sikkim is hence the dampest region 

 of the whole Himalaya. *'" 



The valleys on the south-western side of the Singalela ridge are 

 drained by the Mechi, the Balasan, and the Maha- 



Drainage. 



naddi, the last of which, after receiving the other 



* Himalayan Journals, Vol. II, p. 388. 



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