REVELATIONS OF THE YO SEMITE VALLEY 



79 



Weathering of Concentric Layers of Granite Domes. 



remains below the base of El Capitan, and which he believes dammed 

 the downflowing waters and formed a lake six miles in length. Sub- 

 sequently, sediments filled Lake Yosemite until they made the en- 

 trancingly beautiful meadows of to-day. A continuation of this 

 process is now beheld in the outgrowing delta of Tenaya Creek which 

 gradually is encroaching upon Mirror Lake. 



Messrs. Matthes and Calkins of the Geological Survey have inti- 

 mated to the writer that the forthcoming report of their latest recon- 

 noissance will endeavor to prove that the Yosemite Valley was produced 

 almost entirely by various forces of erosion as revealed by their inves- 

 tigation of the influence of corrasive forces upon the fissured zones of 

 granite. They are now looking for such concrete evidence. 



Conclusions Based on Concrete Facts 



In this summary of the several theories of the genesis of the 

 Yosemite, the general drift of their method of presentation has been 

 to lead to a few conclusions based on concrete facts. But, perhaps, the 

 first and most logical conclusion is that the evidence is still far from 

 being complete. Local geologists, however, have much faith that some 

 new discoveries are about to be made public by the government inves- 

 tigators. The absence of rock sills outcropping along the rim of the 

 valley has been explained as being due to their overburden of detritus." 

 And yet there are reasons for believing that the solid bottom of the 

 Yosemite did actually subside during the period of upheavals and dis- 

 locations. The enigmatic formation of the domes suggests the expan- 

 sion of plastic masses of igneous rocks. If these waves of stone once 

 swelled to such stupendous heights, there must have been intervening 

 troughs. And so, the original sinking away of the yalley floor along the 

 lines of cross-fracture still is obvious to many competent observers. 



