Niagara Falls 



from the northern United States. At first it was thought to be a 

 very simple problem. Given a gorge seven miles long, known to 

 be lengthening annually by a definite number of feet and inches, 

 we can ascertain the number of years required by dividing the 

 sum total of feet by the annual recession. This result is believed 

 to represent the period that has elapsed since the ice age, because 

 the Niagara River commenced its existence in consequence of 

 the damming of the ancient Erie (Erigan) River. The original 

 channel having been blocked, Lake Erie accumulated, and its 

 lowest line of exit was by way of the Niagara River. Sir 

 Charles Lyell in 1841 estimated this period to have been about 

 36,000 years. He supposed the annual wear to be one foot. 

 The latest figures indicate the amount of recession to be four 

 times as great. Hence, if there were nothing more to be said, 

 our conclusion must be that the time needed was only one-fourth 

 of 36,000. 



But this estimate must be modified by a careful consideration 

 of various factors. It must be conceded that the Niagara River 

 began to flow only after the obliteration of the Erigan Channel. 

 Then the peculiar elbow at the whirlpool indicates a second 

 blockade, and consequent divergence of the river toward Lewis- 

 ton; for in none of the numerous canons of the West do we 

 find any such arrangement. The gorge varies greatly in width 

 and depth, as if the volume of the river had been diminished at 

 times. Again, the work may have been interrupted by another 

 glacial blockade, or modified by the presence of lakes not now 

 existent. The story of the gorge, then, shows much compli- 

 cation. It will be our task to state what the principal events in 

 the history of this region have been, so as to be able to judge 

 of the value of computations based upon the work performed. 



• • • • • 



In the study of the geological history of the vicinity of Niagara, 

 three great periods may be designated, each characterized by 

 peculiar conditions. First, the laying down of the crystalline 

 foundations; second, the deposition of the Silurian and later 



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