23S NILGHIRI HILLS. 



whale-hacked than on the Neelgherries Proper, and the valleys, especially 

 those of the main streams, assuming more of the gorge-like aspect. 



The cause of this variation of physical character in the Himalayas, 

 the Kundahs and the Neelgherries Proper, is to be found in the vary- 

 inc amount of fresh water erosion to which each of these hill tracts 



-r, ■ rT, 1 •» has been subject, and this in its turn is depen- 



Kam-fall and its re- j ' i 



^"^'^- dent on the rain-fall, and the area of the system 



of drainage in each locality. There is reason to believe that the 

 Himalayas, as well as the Neelgherries, have been originally exposed 

 to marine action, and this at even a later period than the Neel- 

 gherries ; but the great deposit of moisture, in the form of rain 

 and snow, which takes place over the Southern slopes of the Hima- 

 layas during the South-East Monsoon, collecting in streams and 

 glaciers, long ago ploughed out deep valleys through the entire moun- 

 tain mass, the rock of which, although a gneiss very similar to that 

 of the Neelgherries, is far more rapidly decomposed, owing to the dense 

 vegetation with which it is covered. In the case of the Kundahs, 

 the amount of rain-fall is as great as that on the wettest part ot the 

 Himalayas,* the Kundahs being so situated as to receive the full force 

 of the South-West Monsoon, which blows from May to September, 

 and deposits over these hills and the Western Ghats the vast torrents 

 of vapour collected in its passage over the Indian Ocean. The rain-fall 

 on the Kundahs is thus far greater than on the Neelgherries, which 

 are to some extent, protected by the former from the effects of the 

 South-East Monsoon, and where the rain-fall consequently does not 

 exceed about 90 inches, and hence the Neelgherries, although of larger 

 area, exhibit less extensive erosion than the Kundah Subdivision of 

 the same hill-group. 



* It has been stated to be as much as 250 inches at Sispara whereas the r.ain-fall of 

 Darjeeling is only 130 inches. At Khersiong, howe%'er, the position of which more resem- 

 bles that of Sispava, the rain-fall must be much greater than at Tarjeeling. 



