Whirlpool and Rapids below the Falls of Niagara. 



35 



is now seen on the sides of the declivity near Brock's monument. 

 The smooth, scooped out appearance in the solid limestone rock, 

 as before alluded to, indicates that long before the waters were 

 concentrated at the ravine at Qjieenston, they were for ages 

 sweeping over the precipice on each side of the present opening. 

 When the falls had retrograded as far as is represented by the 

 dotted lines in fig. 4, their further progress was arrested by phys- 

 ical changes constantly but slowly going on, according to 

 Lyell, which have so materially changed the surface and condition 



Mr 



Fig. 4. 



The supposed situation of the Falls when near what is now called the Whirlpool. 



S 



The dotted lines mark the deep lateral valley filled with drift, 



towards the Lake. 



for a considerable distance 



of the globe. This was chiefly the submergence of the whole 

 table-land, which, Mr. Lyell, in his work before referred to. says, 

 caused the valley to be filled up and also covered the table-land 

 itself with drift, which in some places is three hundred feet deep. 



again 



waters 



the sea retired, exposing the precipice over which the 

 would rush. But their direction, from the great inequalities ot 

 the surface arising from the accumulations ot drift, might be 

 changed, and instead of continuing to plough out for itself a 



• •. <* i i ___• l* £^«iNr ha nrmfflntratftd about 



N 



passa 



