Chap. I] general description of rocks. 19 



the local fauna and flora which existed throughout the period including 

 these two formations. At the same time, knowing how intimate is the 

 relation between the amount of change in organic and inorganic nature, I 

 would venture to anticipate that, when fully investigated, the successive 

 phases of life in this region, during the entire and prolonged period repre- 

 sented by the great Sub-Himalayan series, will be found to exhibit an 

 intimate interdependence, corresponding to that which I shall show must 

 have existed in the successive conditions of rock formation during the 

 same period. 



A most interesting subject of consideration in connection with the 



Relations of past and Sivalik rocks is their relation to the great undis- 



present conditions. turbed deposits of tlie i n d -Gangetic plains. Save 



for the one feature of being in their original position of deposition, 

 the Ganges valley deposits have as close an affinity to the Sivalik group 

 as this has to the Nahun group, and might take rank as a fourth and 

 uppermost member of the series. The comparison is most useful, as 

 helping us to attach a proper value to the relations between the older 

 groups. The upper beds of the Sivaliks, as for instance in the range 

 between the Pinjor dun and the plains, are identical in composition and 

 mode of bedding with the deposits of the plains. There is further 

 scarcely a shade of difference in their degree of induration. These deposits 

 overlap the denuded base of the Sivalik hills, just as the Sivalik rocks 

 overlap the denuded base of the Nahun hills. The actual relation of the 

 newer strata to those of the Sivalik hills is precisely what I conceive that 

 of the Sivalik deposits to have been to similar hills of the Nahun rocks, 

 before they were crushed against each other by some slow irresistible 

 lateral force. The infinitely graduated transition between past and 

 present conditions, as suggested by these facts, has been very forcibly 

 brought to my mind during the study of these rocks, and, from the 

 least expected quarter, namely, that of disturbing causes. A most 

 marked coincidence is observable between the variations of the Sivalik 



