Chap. VI] geneeal structure of hills. 171 



modified by disturbing action rather than altogether due to this latter 

 cause. In their position as the fringing band of the higher mountains, 

 these limestones and shaly slates exhibit the sharply crushed type of 

 contortion rather than the large waving of the older rocks. Various 

 arguments, as already detailed, have referred these Krol rocks to two 

 very different periods, the older palseozoic and the older nuinmulitic. The 

 general argument here stated can scarcely be assumed in favour of either 

 view, though we are predisposed to give it in favour of the latter ; its only 

 direct and independent bearing is upon the question of the mountain struc- 

 ture. The age of this group, and the identification of it at different points of 

 the chain, seem to me the most pressing questions in Himalayan geology. 

 We next come to consider the state of the older rocks. In them we 

 Older system of dis- ^ n( ^ the same grand rule obtains as in the newest 

 Sivalik strata, namely, a prevailing north-easterly 

 dip, — folded or normal flexures directed from the north-east. In 



accordance with the strictly elevatory theory he 

 Colonel Strachey's J 



views on the prevailing adopted, Colonel Strachey (Quar. Jour. Geol. Soc, 

 north-east dip. 



London, Vol. X., p. 252) explains the feature in 



both cases alike, by a repetition of the same phenomenon of upheaval. 

 The most difficult part of the question is assumed, namely, the initial 

 stage of the phenomenon, which seems to me could never result, indeed 

 would be the very contrary of what one must expect, from the conditions 

 of Mr. Hopkins' theory. The appropriate inclination, however, having 

 been once imparted to the great blocks of the earth's crust between the 

 fissures, the recurrence and constant increase of the inclination is account- 

 ed for by the fact that the resultant of upward pressure would not pass 

 through the centre of gravity of the inclined block ; the Sivalik strata 

 having been deposited upon the denuded edge of these tilted blocks, 



acquired the dip due to the subsequent tendency 

 Objections. J 



to revolve when the block is pressed from below. 

 The detailed features we have observed in the Sub-Himalayan rocks 



