92 
Fall, from the time it commenced its work at the ‘ heights,’ seven miles below 
its present position, according to Lyell’s statement as to the gorge of 
Niagara River, was not greater than the present Canadian Fall. Adding 
together the present work done by both Falls, we should have about 35 feet 
per annum as the backward work performed when the entire volume poured 
over a single Fall of the width of the present Canadian Fall. 
“ At this rate 10,000 years would seem sufficient time for the cutting out 
of the present gorge terminating at the ‘heights’ towards Lake Ontario,” 
instead of 35,000 years, the hitherto accepted estimate of Lyell, which 
was arrived at in the absence of the more perfect data which modern 
research has placed within our reach. 
