458 GEOLOGICAL EXCURSION TO THE ROCKT MOUNTAINS. 



partly on limestone ledges of the OlintOll, and partly on fallen blocks 

 of Niagara limestone. From the Canadian side one can enter a tunnel 

 dug in the Niagara shale, and follow it to a point beneath the Horse- 

 shoe tall, whence Ik; can look out at the descending water. At numer- 

 ous points farther down stream stairways, elevators, and inclined rail- 

 ways are constructed to enable the visitor to reach the water's edge. 

 Those of most value to the geologist are on the American side at the 

 Whirlpool Rapids, and on the Canadian side at the Whirlpool. From 

 the latter a few minutes' walk takes one to the mass of drift oiling the 

 preglacial channel, and its contact with the older rocks can be seen. 

 The accompanying sketch (Pig. 28) was made by iM. Golliez, of the 

 visiting geologists. 



Flu. 28.— The Whirlpool of the Niagara River. 



