44 



GUIDEBOOK OF THE WESTERN UNITED STATES. 



q.uojj. uieq.ui 



cj, o o_ c>. .o_ o o_ 



CJ -^ O fff (0 f~ \0 



surface of this plain is the deep 



<p and perfect disintegration of the 



'^ granite rock which composes all 



I this country. No ledges of rock 



^ can be seen, and the soil is made up 



Z largely of small fragments of gran- 



■3 ite broken up by the action of the 



S" weather. This even surface is 



a 



a well shown in Plates XV, A (p. 31) , 



"§ and XXIV, A, and its relation 



- to Pikes Peak is shown in fig- 



I ure 11. 



o 



Z This plateau can be traced north- 



^ Avard at least as far as Denver. It 



M is the result of long exposure to the 



a action of the weather and the cut- 



•3 ting of the streams when the entire 



§ region was at a much lower level 



a than it is to-day — so low, in fact, 



5 that the streams could cut no 



lower — and it remained in this 

 .2 position so long that most of the 



1 hills and other inequalities of the 

 oj surface were worn away and the 

 ^ region was reduced to a plain as 

 •g truly as the country about Denver 

 •a and Colorado Springs is a plain to- 

 ^ day. That was long, long ago, as 

 U man measures time, even before 

 ^ man was there to see any of 

 g the operations that produced the 

 g change. 



•^ Then came a slow but steady up- 



a lift of the mountain region and 



a probably also of the plain, until 



§ the land reached its present height 



5 above sea level. Such an uplift 



J accelerated the streams, and they 



1 soon cut deep canyons — such as Ute 

 ^ Pass and the canyon of Cascade 



2 Creek — in the surface of the pla- 

 I teau, until to-day it is level only as 



S one looks across broad tracts of its 



g old surface and at a distance so 



I great that the details fade and the 



plain looks as it once did before 



