STRAT1GRAPHICAL FEATURES. 49 



At present only the age of the trap is certain ; that of the granite, 

 in the absence of better proof, I consider as greater and to come in 

 chronological order immediately before the trap, perhaps in late ere* 

 taceous times. In that case it would follow that the southern flexures 

 and dislocations are of older date than the northern, as for instance the 

 northern or Tibetan fault-folds. Indeed, this supposition is supported 

 by other evidence, to which I shall refer later on, namely, the fact 

 that fresh folds are being added to the system along its north-western 

 margin. 



2* H aim ant a system. 



Between the metamorphicand semi-metamorphic schists (vaikritas) 



of the southern chain of the Central Himalayas. 



Distribution. m J 



and the lower silurians, we find a great thickness 



of strata, which form one of the most important features of the Central 



Himalayan sections. Although almost entirely destitute of organic 



remains and partly altered by the granite intrusions, this system is 



nevertheless so constant in lithological and structural characters, that it 



must be separated from the overlying lower silurians. Between the 



Nep£l frontier and Spiti it forms more or less a continuous belt; it is 



well developed in the eastern sections, narrows gradually in Garhwcil, 



then widens considerably in Bissahir, and finally in Spiti is seen as a 



belt of some 10 to 20 miles in width. Some of the highest peaks lie 



within this belt of semi-altered rocks. 



The boundary between the schists (vaikritas) and gneiss of the 



metamorphic zone and the distinctly sediment- 

 Boundaries. 1 , 1 • 1 r ,i , • 



ary beds which iorm the haimanta system is not 



very strongly marked; the passage is nearly everywhere gradual. On 

 the other hand, the upper boundary of the system is perfectly distinct ; 

 the haimantas are invariably separated from the silurians by a zone of 

 bright red quartz shales, which I have traced from the extreme north- 

 western limit of my area (Spiti) to the frontiers of NepaT The haimanta 

 system is enclosed conformably between the vaikritas and the silu- 

 rians. 



E ( 49 ) 



