36 Whirlpool and Rapids below the Falls of Niagara. 
the whirlpool was formed. ; 
On the falls retreating from the whirlpool, it will be noticed, 
that the hard quartzose rock, 2, fig. 2, would form the base of 
the falls, and then an obstruction would be made to the free 
egress of the water; the hard rocks would then fall on this pave- 
ment, which would greatly increase the obstruction and give rise 
to the rapids, and this would continue as the falls receded, until 
by the indication of the strata, this hard rock would by degrees 
sink so low as to allow a depth sufficient for the waters to — 
without commotion. This will be evident by an inspection © 
fig. 2, the stratum, 3, being soft shale. The inclination of the 
strata and the soft character of the rocks through which the rivet 
flows at the falls, are the causes of that apparently miraculous 
15° . . é . tely after the 
prised me more than the falls themselves. 
