196 



Sierra Club Bulletin 



That fossils were created as they occur in the rocks, is an 

 ancient doctrine, now so little believed that geologists are spared 

 the pains of proving that nature ever deals in fragmentary crea- 

 tions of any sort. All of our valleys are clearly fragmentary 

 in some degree. Fig. 3 is a section across Yosemite Valley from 



Fig. 3 



Indian Canon, which displays the stumps of slabs and columns 

 of which the granite is here composed. Now, the complements 

 of these broken rocks must have occupied all, or part, or more 

 than all of the two portions of the valley, A C D and B E F. 

 The bottom, A B, is covered with drift, but we may assume 

 that if it were laid bare we would find it made up of the ends of 

 slabs and columns like the sides, which filled the space A C E B ; 

 because in all valleys where the bottom is naked, the broken 

 stumps do appear, showing that this valley was not formed by a 

 fold in the mountain surface, or by a splitting asunder, or by 



Fig. 4. 



subsidence, but by a breaking up and translation of rocks which 

 occupied its place ; or, in other words, by erosion. 



