

Ch. XV.] 



FALLS OF NIAGARA. 



3d 



adequate cause for executing the whole task thus assigned to 

 it provided we grant sufficient time for its completion. As 

 this part of the country was a wilderness till near the end of 

 the last century, we can obtain no accurate data for esti- 



the exact rate at which the cataract has been 

 Mr. Bakewell, son of the eminent geologist of 



mating 

 receding. 



Niagara in 1829, made 



attempt to calculate from the observations of one who had 

 lived forty years at the Falls, and who had been the first 

 settler there, that the cataract had during that period gone 

 back about a yard annually. But after the 



most 



my 



spot in 1841-2, I came to the conclusion that the average of 



one foot a year would be a much more probable conjecture. 

 In that case, it would have required 35,000 years for the 

 retreat of the Falls, from the escarpment of Queenstown to 

 their present site. It seems by no means improbable that 

 such a result would be no exaggeration of the truth, although 



rade movement has been 

 uniform. An examination of the geological structure of the 

 district, as laid open in the ravine, shows that at every step 

 in the process of excavation, the height of the precipice, the 

 hardness of the materials at its base, and the quantity of 



fallen matter to be 



must 



At some 



may have receded much 



in general its progress was probably slower, because the 



cataract, when it began to recede, must have had nearly 

 twice its present height, and therefore twice the quantity of 

 rock to remove. 



made by me 



advantage of being accompanied by Mr. Hall, State geologist 

 of New York, and in 1842, when I re-examined the Niagara 

 district, I obtained geological evidence of the former exist- 

 ence of an old river-bed, which, I have no doubt, indicates the 

 original channel through which the waters once flowed from 



Q 



m 



monuments 



of the present gorge. The geological 



^ j_ — — <_, _, 



forty feet thick, containing fluviatile shells of the genera 



