Ix INTRODUCTION. 



When the Gfreat Basin came into existoncCj or rather 

 emerged from the water, tliere were dry lands and moimtams 

 east, west, and nortli of it, shutting out fi'om it the moisture 

 of the Pacific Ocean, as well as any that might travel 

 thither from the far-off Gulf of Mexico. The climate may 

 he considered to have been then not unlike that of the present 

 time, so that the rain-fall was far less, even in the ncw-l)oni 

 "Basin Eegion," than it was over the Colorado Basin m its 

 primeval state, which was then washed hy a broad Pacific 

 Ocean. The effect of these climatic peculiarities was that a 

 sufficient quantity of rain never fell upon the "Basin Eegion 

 to form a complete system of drainage from the highest lands 

 down to the sea. 



"We can easily conceive that, in the formation of an extensile 

 drainage system, the little primitive streams form lakes at tne 

 first serious obstacle met with in their course. These lakes, 



full to overflowing, find at lenirth some outlet 



come 



lel of exit deeper and deeper, until the obstacle is 

 , and the lake drained. Thus lake after lake is 

 formed, and disappears as «ach succeeding obstruction is cu 

 tlu-ough, until the independent streams, having sought the 

 lowest levels of the country, imite their waters into a single 

 channel, and so pass into the sea. There is nothing whatever 

 in the physical construction of the Great Basin to have pre- 

 vented the formation of one great river, emptying into the (j 

 of California, either as an independent stream or as a tributa 

 of the Eio Colorado. It is not because the Great Basin 

 really a complete basin without an outlet, or 



ry 



rica 



insiu-mountable barrier to the drainage,^ 



but rather because it is ^^ 

 .n of perhaps hundi-eds oi 

 basins, which have alwavs remained in their primitive isola 



basin 



