GENERAL CONSIDERATIONS, 123 



I think the question is best answered by reference to the south edge 

 of the Kotah dun, where we have the Siwalik conglomerate very little 

 disturbed as a whole, and therefore more likely to shew the prelimi- 

 nary stages in the development of any marginal fault that may occur. 

 We see there at the south edge of the hills a rapid bending over of the 

 beds towards the vertical, with even inversion as in the Ladwa gddh. 

 That accelerated dip in the more disturbed areas of the Siwalik 

 rocks further west has vanished, and the problem is, how ? Taking 

 a definite portion of the country south of the Pdtli dun (see section 

 V), what has become of the southern half of the normal (unsymme- 

 trical) anticlinal in the sand-rock and Siwalik conglomerate, which we 

 may assume by analogy was once present ? There is no reason to sup- 

 pose it denuded away entirely any more than the northern half ; but 

 there is strong reason for believing that, if we accentuate the earth 

 movements which in the gently undulating area of the Kotah dun 

 were nevertheless able to produce so sharp a bending to the south with 

 slight inversion, we shall arrive, in the more crushed area of the P£tli 

 dun, to a state of complete inversion and production of a fold-fault. 

 The normal fold with its sharp " dejettement" to the south must re- 

 sult in an inversed fold, or sigma-flexure, when further crushing has 

 supervened ; and the latter will inevitably carry with it a fold-fault of 

 the nature of those about which I have already written sufficiently. 



I see no escape therefore from the general conclusion that, where- 

 ver the southern margin of the Siwaliks shews no relic of a " dejette- 

 ment" to the south, it is because a fold- fault has supervened along 

 what is now a limit of deposition for the Bhctbar zone of gravels, sands 

 and clays. 



How different is the structure of this fringing zone of Sub-Hima- 



Contrast of the south ^^ r0cks fr0m that ° f the eaStem counties 



face of the Himalaya f England ! As we travel inland from the shores 



with the eastern aspect 



of England. of the North Sea, we ascend over strata succes- 



sively older; our feet tread first the Tertiary or the post-Pliocene 

 boulder clays, then the cretaceous chalk formation, then the Neoco- 

 mian,then the oolites, and so on ; whilst every one of these strata dips, 



( 181 > 



