The Rocks of the John Day Valley. 169 



remained sand; if gravel, remained so, unal- 

 tered even now. 



Long after that heaviest deluge of ashes 

 had settled down into permanent rock, a new 

 chapter was opened in the life record of these 

 lake shores. The stratified materials that re- 

 ceived these later records were washed from 

 either shore into remarkably uniform slopes 

 toward the middle line of the lake depression. 

 These slopes were evidently once continuous 

 along both sides of the valley, but since the 

 lake was drained off by the deeper wearing of 

 its outlet, every little stream from the sur- 

 rounding hills has cut its own ravine through 

 these stratified sands, gravels and clays, until 

 what was once continuous is now cut up into 

 the remarkably uniform series of ridges whose 

 summit outlines stand in fine perspective as 

 far as the eye can reach. In the ravines that 

 separate these ridges the gold of this region is 

 found, and in the diggings that result, the 

 bones, teeth and tusks of the elephant are 

 often uncovered, a few of which have been 

 preserved. In the loose m?/eria 1 s that form 



