524 Annual Meeting. [May 1, 



are equally high, in the valleys beyond the great eastern escarpment 

 the drift still exists, which would not have been the case had gla- 

 ciers filled these valleys during emergence in the way that took 

 place in the Passes of Llanberis and Nant-Francon, and in parts of 

 the Highlands of Scotland. 



It has been stated above that the upper plain around Lake 

 Erie, and the lower plain of Lake Ontario, are alike covered with 

 drift. Part of this was formed, and much of it modified during 

 the emergence of the country. In the valley of the St. Lawrence, 

 near Montreal, about 100 feet above the river, there are beds of 

 clay, containing Leda Portlandica, and called by Dr. -Dawson of 

 Montreal, the Leda clay. Dr. Dawson is of opinion that when this 

 clay was formed, the sea in which it was deposited washed the base 

 of the old coast line that now makes the great escarpment at 

 Queenston and Lewiston, overlooking the plains round Lake Ontario. 

 It has long been an accepted belief that the Falls of Niagara com- 

 menced at the edge of this escarpment, and that the gorge has 

 gradually been produced by the river wearing its way back for 

 seven miles to the place of the present Falls.* In this case, the 

 author conceives that the Falls commenced during the deposition of 

 the Leda clay, or near the close of the drift period, when during 

 the emergence of the country the escarpment had already risen 

 partly above water. If it should ever prove possible to determine 

 the actual rate of recession of the Falls, we shall thus have data 

 by which to determine approximately the time that has elapsed 

 since the close of the drift period ; and an important step may thus 

 be gained towards the actual estimate of a portion of geological 

 time. 



[A. C. R.] 



ANNUAL MEETING, 

 Saturday, May 1. 



The Duke of Northumberland, K.G. F.R.S., President, 

 in the Chair. 



The Annual Report of the Committee of Visitors was read, and 

 adopted. 



The statement of Sums Received shows a steady and gradual 



* The details on which this belief is founded, may be found in the writings 

 of Professor Hall, of Albany, and Sir Charles Lyell. 



