34 



TRANSACTIONS OF THE 



[Ses 



the long axis as the result of uplift, and therefore strained 

 in a direction at right angles to that axis. The uplift 

 might then be to some extent compressed and shortened, 

 and later it might even ruckle slightl}^ ; but eventually if 

 the pressure were continued and the mass as a whole did 

 not move, then, unless the direction in which the pressure 

 acted was coincident with the axis of ujjlift, one of two 

 things must happen : (i) overthrusting of parts of the range, 

 or (ii) bending at right angles to the axis, to be followed by 

 its slewing and eventual shearing. Thus, if the pressure 

 were maintained, we should, in the second case, get structures 

 like the following, as seen in plan, the arrow showing the 

 direction in which the pressure is supposed to act. (AB 

 represents the axis of the original uplift.) 



In (vii) shearing has taken place, and the broken ends C C 

 of the axis now overlap. In the last three, the pressure is 

 acting at an angle to the axis. 



Imagine these forces (how produced is immaterial, but 

 I have previously suggested a shifting eastwards of the 

 Himalayas to account f(jr the ridging along the border 

 country) at work on a large scale over a wide extent of 

 country, and the pressure to continue after the shearing of 

 the main E.W. uplift (not necessarily a simple syncline) as 

 illustrated. The force is, let it be remembered, acting in a 

 direction more or less at right angles to the lines of weak- 

 ness already set up by stress in the adjacent crust, owing 

 to that uplift. We should then get, in place of the original 

 lines of weakness, a series of parallel ridges and hollows 

 (anticlines and synclines) running at right angles to the 

 long axis of the original uplift, beginning between their 

 broken ends (C in above diagram), and continuing a longer 

 or shorter distance to north and south, according to circum- 



