502 SEE— ORIGIN OF HIMALAYA MOUNTAINS. [April i8, 



If we examine a good map of northern India, we shall find not 

 only that the Indus and Ganges now flow in the ancient sea valley 

 formerly depressed below the weaves, and now elevated less than 

 i,ooo feet above the ocean; but also that this valley made a sharp 

 bend in north central India. It has the form of the Greek letter 

 lambda, A, with the Ganges leg of the lambda by far the longest, and 

 the included angle about 105°. 



If the lava expelled from beneath this ancient sea valley came 

 from two directions, at such an angle, the forces of uplift naturally 

 would accumulate at the head of the Sea Valley. For they would 

 come from the southeast and also from the southwest, as well as 

 from the south ; and the result of compounding these forces would 

 be magnified forces of unusual intensity, directed to the elevation of 

 the Himalayas of north central India. This is exactly what has 

 taken place ; and hence we see why the plateau of Tibet is so high in 

 the western part of that great " roof of the world." 



If now we turn to the region of Lake Titicaca, in South 

 America, we find an exactly similar relative situation. The coast 

 from the south and northwest meet at an angle of some 135° ; and 

 the forces producing the uplift have come from the two directions; 

 and also from the west. The result has been a convergence of the 

 forces tending to produce an uplift; but as the angle of 135° is less 

 acute than in northern India, where the angle is 105°, it is not 

 remarkable that the plateau of Titicaca is less elevated than that of 

 western Tibet, where the forces converged more powerfully and 

 were so compounded as to produce the maximum elevation. 



It certainly is not accidental that these two highest plateaus of 

 the world stand in similar centers of converging forces directed 

 from the ocean; and that the higher plateau of Western Tibet has 

 the forces converging at the smaller angle of 105°, and therefore 

 compounding more effectively to produce a greater power of uplift, 

 for equal energy directed from the side of the sea. 



And as the observed phenomena confirm the theory in every de- 

 tail, one finds it very difficult to believe that any other cause has 

 shaped these stupendous uplifts of the earth's crust. 



It is also easy to see why the heights of the plateau of Tibet is 



