6:1 MALLET : GEOLOGY OF DARJILING AND WESTERN DUARS. 



generally are ; yet the alternations of foliated quartzites, slates, carbona- 

 ceous and graphitic schists, and crushed seams of coal, are easily recog- 

 nizable as Damiidas by any one accustomed to the Darjiling rocks, and 

 are quite unlike anything met with in the Dalings. The Daling graphitic 

 schists occur but rarely, and in isolated beds, generally of trifling 

 thickness. They only contain a few per cent, of carbon, and have clearly 

 been formed out of some variety of carbonaceous shale, not out of coal. 

 I have never observed anything like true coal in the upper series. 



The same remark applies to the rocks coloured as gneiss, in which I 

 nowhere observed any beds that I had reason to suspect were still- 

 further-altered Damudas. The secondary folds of the main synclinal 

 (p. 10) are not on a sufficiently grand scale to bring the lower rocks to 

 the surface. 



It is not impossible that beyond this synclinal, in Independent 

 Sikkim, where the foldings of the strata are comparatively unknown, 

 outcrops of the Damuda series may yet be found. Neither Hooker nor 

 S her will, however, in the journals of their travels in that country, describe 

 any rocks recognizable as such. 



The occurrence of Damudas in the Darjiling Himalayas adds a 



wide expanse to the area within which these rocks 

 Probable existence of ' . , 1 . 



Damudas beneath Gan- are known to have been deposited, at least m 



patches. It is fairly inferable that such was the 



case over the country now occupied by the alluvial plains of the Ganges 



between Rajmahal and the foot of the Darjiling hills, and extending for 



an unknown distance to east and west ; and it is further probable that 



there still exist beneath those plains, coal-fields equal, perhaps, in value 



to those which now supply Bengal with fuel. 



The difficulties in the way of finding such are, however, manifest: 

 \stly 3 the unknown depth of the Gangetic alluvium, which is certainly 

 sufficient to make boring extremely expensive, and may be so great as to 

 render mining impracticable ; Zndfy, the small proportion of the total 



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