100 Geology and Topog7-aphy of Western New York. 



plate them acting in concert with the river current, we cease to 

 wonder that the chasm should have attained its present length 

 and depth, and that the cataract should occupy a place at the dis- 

 tance of seven miles above its apparent natural position. 



How much is due to each agent separately, can hardly be de- 

 termined. We must bear in mind, however, that the fall was 

 nothing at first ; that as the elevation advanced, the river became 

 more rapid ; that finally, when the limestone was cut through 

 and somewhat undermined by the disintegration of the shale be- 

 low, and not till then, a distinct cataract could have been produ- 

 ced. Until then, the tides and dashing of the surf were probably 

 most efficient in tearing up the strata from their rocky beds, and 

 comminuting the fragments; while the river would guide the 

 course of their operations, and remove the detrital matter from 

 its bed. 



What distance the cataract has receded since that time, is a 

 problem equally difficult to solve ; but there are some indications 

 which will enable us to approximate to the truth. The rapids 

 above the cataract, and the whirlpool below, are points where 

 phenomena exist incompatible with the common theory. If it 

 should be established, that the conformation of the _whir] pool is 

 such, that it could not have resulted on the theory of recession, 

 this " endless saw" must relinquish its claim to four long miles of 

 excavation for which it has received credit. And if the rapids 

 above the cataract existed prior to its present location, we may 

 presume that they are but the upper extremity of an ancient in- 

 clined plane, or rather, succession of ledges, which existed before 

 the limestone strata were cut through. 



Goat Island is situated on the brink of the precipice, and di- 

 vides the water into two unequal sheets. It is based on the hme- 

 stone ledges which form the rapids, and the highest part of its 

 surface is on a level with the river above their commencement. 

 Near the upper extremity of the island, the rocky bed rises just 

 sufficiently above the surface of the river to divide the stream, 

 and deflect the branches somewhat from the original course of 

 the current. It is to this circumstance alone that the island owes 

 its existence ; for its lower extremity is covered with a tertiary 

 deposit of gravel and clay, which can ofljer no adequate resist- 

 ance to the boisterous current, which seems anxious and ready 

 to sweep the whole island into the gulf below. 



