326 THE MOUNTAINS OF CALIFORNIA 



thick sheets of lava. These are known as the 

 "Dead Elvers of California," and the gravel de 

 posited in them is comprehensively called the 

 " Blue Lead." In some places the channels of the 

 present rivers trend in the same direction, or 

 nearly so, as those of the ancient rivers; but, in 

 general, there is little correspondence between 

 them, the entire drainage having been changed, or, 

 rather, made new. Many of the hills of the an 

 cient landscapes have become hollows, and the 

 old hollows have become hills. Therefore the 

 fragmentary channels, with their loads of aurifer 

 ous gravel, occur in all kinds of unthought-of 

 places, trending obliquely, or even at right angles 

 to the present drainage, across the tops of lofty 

 ridges or far beneath them, presenting impressive 

 illustrations of the magnitude of the changes ac 

 complished since those ancient streams were anni 

 hilated. The last volcanic period preceding the 

 regeneration of the Sierra landscapes seems to 

 have come on over all the range almost simulta 

 neously, like the glacial period, notwithstanding 

 lavas of different age occur together in many 

 places, indicating numerous periods of activity in 

 the Sierra fire-fountains. The most important of 

 the ancient river-channels in this region is a sec 

 tion that extends from the south side of the town 

 beneath Coyote Creek and the ridge beyond it 

 to the Canon of the Stanislaus ; but on account of 

 its depth below the general surface of the present 

 valleys the rich gold gravels it is known to contain 

 cannot be easily worked on a large scale. Their 

 extraordinary richness may be inferred from the 



