130 W. M. Davis—Gorges and Waterfalls. 
. other examples are named. 
That this clear description was not generally appreciated is 
shown in a later account of the same gorge, where although it 
is recognized as of aqueous origin, wonder is expressed that the 
downward erosion should have so greatly exceeded the lateral 
drainage system. The long 3 feats time of land-existence 
gave our rivers east of the Mississippi ample opportunity to 
perfect their courses; to destroy all the lakes that must have 
existed in great numbers while the land was rising and the 
mountains were growing; to wear back all the falls until they 
their accustome 
quite bewildered and lost their way among the heaps and 
sheets of drift that masked their old valleys, and had to settle 
down as best they might on the lowest ground they could find. 
* Dougall, Falls of Clyde, Trans. Geol. Soc. Glasgow, iii, 51, 1871. 
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