Niagara Falls 

 1895 figures 22 and 23, in order to appreciate the insignificance of 



Spencer , i • i 1 



the whirlpool ravine. 



The form of the whirlpool cauldron requires explanation. At 

 Mr. Shepherd's house, a short distance west of the whirlpool, 

 there is a well 90 feet deep without reaching rock (n>, fig. 19) 

 and this shows the absence of Niagara limestones to a depth of 

 more than 50 feet below the surface rocks of the western wall 

 of the whirlpool. At that point the limestones rise 40 feet higher 

 on the eastern side of the river than on the western, but the 

 depression was leveled up with drift. Thus it appears that at 

 this point the Niagara river took possession of the eastern side 

 of a drift-filled valley (Tonawanda-St. David's), and the whirl- 

 pool ravine was a little tributary to it. When the falls had 

 receded to the whirlpool and penetrated the rocky barrier, the 

 currents were able to remove the filling of the buried ravine, and 

 this gave rise to the form of the cauldron, which deepened its 

 basin to lower levels by the currents of the river acting upon the 

 underlying soft shales, with the landslides obscuring the older 

 features. It is evident that there was no preglacial Niagara 

 river. 



The Niagara river crossed the broad shallow depression 

 of the Tonawanda drainage, at the falls and that adjacent to 

 the whirlpool on a basement of drift, but elsewhere generally 

 on hard limestones. Out of both of these materials, terraces 

 were carved thus marking the old river level, before it sunk 

 within the chasm. 



Sketch of the Lake History and the Nativity of the Falls 



. . . At the commencement of the Lacustrine epoch, 

 Warren water gulf covered most of the Lake region, and Forest 

 beach was its last strand. Afterwards the waters sank 1 50 feet, 

 thereby dismembering Warren water gulf into Algonquin Gulf 



592 



