Once while strolling through a forested flat 

 in central Colorado, I concluded from the to- 

 pography of the country that it must formerly 

 have been a glacier lake. I procured tools and 

 sank a shaft into the earth between the spruces. 

 At a depth of two feet was a gravelly soil-de- 

 posit, and beneath this a matting of willow roots 

 and sedge roots and stalks. These rested in a 

 kind of turf at water-level, beneath which were 

 boulders, while under these was bed-rock. Nu- 

 merous romantic changes time had made here. 



Many of these meadows are as level as the 

 surface of a lake. Commonly the surface is 

 comparatively smooth, even though one edge 

 may be higher than the other. I measured one 

 meadow that was three thousand feet long by 

 two hundred and fifty feet wide. Tree-ranks 

 of the surrounding forest crowded to its very 

 edge. On the north the country extended away 

 only a foot or two higher than meadow-level. 

 On the south a mountain rose steeply, and this 

 surface of the meadow was four feet higher than 

 the one opposite. The up-the-mountain end 

 was about three feet higher than the end which 



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