NIAGARA. 
245 
other extremity of the same fall, and a portion of the stream 
passed behind the island and formed a separate small fall at 
right angles to the main Falls. It is known also that at the 
present time the centre portion of the Horse-slioe Fall has 
become more deeply indented than formerly, modifying the 
previous liorse-shoe form that originated the name of the 
fall. 
On considering the whole circumstances, the conclusion 
seems irresistible that the Horse-shoe Fall has gradually cut 
its way all across the front of Goat Island from the end of the 
American Fall to its present position, and that the American 
Fall has not materially changed during that time, except in 
getting partially indented in the centre and somewhat horse¬ 
shoe in form, from the same cause that has given its form to 
the Horse-slioe Fall, namely the greater depth and force of 
current in the middle of the stream than at the sides. 
Further, the conclusion seems irresistible that the same 
cutting away action had previously carried the Horse-slioe 
Fall all across the face of the present American Fall, forming 
in its course the precipice over which that now falls; and 
that in still earlier times the Horse-slioe Fall had similarly 
cut its way all through the seven miles of the present gorge 
from the face of the cliffs at Queenston, where the 
cataract must have commenced. The progress during 
the last two centuries is estimated at about a foot per 
year; but as regards the future progress of Niagara, it 
lias to be noticed that when the Falls have receded another 
mile, they will have reached the open space behind Goat 
Island, and at a second mile distance the river is nearly two 
miles wide, so that the fall will be then three times the total 
width of the present Falls, and the thickness of the sheet of 
w 7 ater proportionately less. The consequence of this will be 
a proportionate reduction in the wearing action of the 
water, and in the rate of the receding of the fall. 
This rate will be also further reduced by the circumstance 
that as the chief breaking down force in action in cutting 
back the present Falls arises from the perishing of the 
supporting shale under the top limestone rock, causing this 
rock to be undermined and break off in masses, and these 
strata are not horizontal but dip backwards, at an inclination 
of about twenty-five feet per mile, when a distance of about 
three miles back has been reached, this cause will have ceased 
from the cropping out of the strata. 
Some other circumstances will thus intervene to affect 
the result, complicating the question and making it a very 
interesting one for consideration. The height of fall of the 
