GENERAL CONSIDERATIONS. I4K 



w elevation of the great range which has supplied the deposits has 

 "been going on." 



I need scarcely remark that the tendency of the general results 

 which I have obtained is to strengthen this conclusion. I have 

 shown indisputably that the margin of the Himalaya in all ages 

 of the Tertiary period has been a line of weakness advancing slowly 

 towards the south ; on one side of which the strata have been thrust 

 southwards and upwards, and on the other side of which they have 

 been thrust northwards and downwards. And not only this but I 

 have given proof in the section south of the Sanguri sot, and in 

 those north of the S£ra N., that the sinking of the plains and the rising 

 of the hills was not an alternating phenomenon as if the one were the 

 forward and the other the backward swing of a pendulum, but that 

 both went on at one and the same time. 



Therefore, by the regularity of the folds and the fold-faults which 

 have affected the Sub-Himalaya, by their parallelism, and by the 

 parallelism and uniformity of elevation and aspect of the different 

 zones between them, by the regular succession of the fold-faults in 

 time through all the ages of the Tertiary period, and by the presence 

 of one in the act of forming between the Recent deposits of the plains 

 and the edge of the hills, it is abundantly evident that further addi- 

 tions of sediment at the foot of the mountain-land was always accom- 

 panied by a sinking of that part and a rising of the denuded area, 

 through the whole of the Tertiary period, and probably through the 

 individual ages represented by each rock stage. 



Recent Himalayan research, therefore, in this direction goes to 

 establish the fact that the crust of the earth is extremely sensible to 

 changes of load on it, that it rises when relieved, and sinks when 

 over-burdened ; and that, therefore, we must adopt some such supposi- 

 tion as that of the author of the " Physics of the Earth's Crust," namely, 

 that a " fluid substratum " exists at some depth beneath the surface 

 in which that crust floats in approximate hydrostatical equilibrium. 



( *99 ) 



