WOOD AND WASTE 15 



into softer strata and gutted out in a few 

 hours this great weight of soil. Some 

 such catastrophe might likewise happen in 

 the far future to the big waterfall. Already 

 there is a cavern extending far beneath the 

 ledge over which the water flows, and 

 proving thereby the existence of a softer 

 rock beneath. 



Should, therefore, the hard upper crust 

 give way or wear out — as must eventually 

 happen — and should the stream's course 

 continue to tap a soft material, the progress 

 lakeward of this deep rift would be relatively 

 rapid. 



The lake basin itself in time would be 

 reached, and its contents of soft alluvium 

 very quickly washed out. Each little rill 

 and brook draining the branch flats would 

 gut out into a gorge; the flats would dis- 

 appear, and the foothills resting on them 

 would in their turn begin to move, until in 

 a short time a steep valley similar in all 

 respects to others in the district would be 

 formed. The lake, in fact, is no more a 

 permanency than are the great conglomerate 

 cliffs of our pumaceous lands, whose every 



