156 SUB-HIMALAYAN EOCKS OF N. W. INDIA. [CHAP. V. 



present level of the stream ; yet in such places I failed to observe any 

 groovings or roundings of the rocky sides. The absence of evidence of 

 this kind may, perhaps, be attributed to the rapidly disintegrating action 

 of the heavy rains. I was many times puzzled to account for the posi- 

 tions in which these erratic blocks occur. They are frequently found on 

 the slopes of the range, out of the way of any of these main gorges, 

 and even up the little receding valleys of streams, which only drain the 

 outer hills, and down which the blocks could not have come. Must we 

 superadd the agency of floating ice ? The total absence of erratic blocks 

 in other positions is often equally puzzling. The position of this glacial 

 deposit more to the west, in the confined and elevated longitudinal 

 valleys between Sihunta and Choari impresses one more forcibly with 

 the antiquity of its origin ; it there lies in gaps and on ledges a full 

 thousand feet over the deep drainage gullies close by. 



In attempting to account for the presence of glacial phenomena at so 



inconsiderable an elevation as 3,000 feet in a 

 Its -possible explana- 

 tion sub-tropical latitude, it were easy to appeal to 



that mysterious ' glacial period' which Mr. T. F. Jamieson has lately 

 (Quar. Jour. Geol. Soc, London, Vol. XIX, p. 257,) suggested in explana- 

 tion of some geological features of the Thibetan regions. I do not at 

 all reject Mr. Jamieson's idea, but I hold that it is only to be called 

 in when all other explanations are found untenable. I would suggest 

 the following. Lofty as the Himalayas now are, I know of no physical 

 hypothesis by which we are, a priori, forbidden to suppose them to 

 have formerly been very much higher, not only by the amount removed 

 by denudation, but as a mass ; and for such a supposition I see some 

 reasonable grounds. Towards the close of the Sivalik period of deposi- 

 tion the Dhaoladhar may have been very much more lofty than now, and 

 its valleys filled with glaciers : in sinking to its present level these would 

 disappear, and the Sivalik strata may have undergone their final foldings. 

 I can find no explanation of the extensive folding of the Sub-Himalayan 



