86 R. Bakewell on the Falls of Niagara. 
Moreover, with regard to the refractory limestone rock, it is 
well known and has often been stated that the limestone at the 
Falls rests on soft shale, only half of the height of the Fall be- 
ing limestone, and this limestone is carried off, not by.the action 
of the waters on it, but by being undermined, through the ero- 
sion of the shale, a rock full of joints, and therefore separatin 
into blocks. The limestone falls away readily when through the 
undermining action it is left without support. We see therefore 
no force in the citation from M. Desor. ; 
Hyvery little torrent has its furrowed channel, and often its 
deep pot-holes, as a result of the action of the water, and it 
would be most strange, if the great flood of Niagara, should : 
Tush on its course for ages and produce no appreciable effect. 
_ A few words on these pot-holes, and the great pot-hole of 
Niagara, before I proceed. Some of these excavations or pot 
holes I have measured in situations where there is little water 
flowing exer in the spring of the year. There are three at 
the Bashapish Falls near Mount Washington, in the state of 
Massachusetts, succeeding each other in a narrow ravi I 
the space of forty yards, One of them was twenty-two fect m 
- depth, independently of the debris at the bottom, the depth of 
which I could not ascertain. The diameter of this circular basin 
was about three yards. If then, a stream of water, active only 
a short period of the year, is capable of making such inroa 
in the hardest rocks, are the Falls of Niagara the only excep- 
tion? Where, it may be asked, are the pot-holes of Niagara? 
I would reply: walk on the precipice of the chasm from Lewiston 
to the Falls, for an answer. Then, in imagination, let the flood 
above the rapids be held back, the river dried up, the whizl- 
pool emptied of its contents; and then we shall have a magnifi- 
cent pot-hole, the largest in the world, with two deeply fluted 
arms stretching north and south, each three miles in length. Asl 
was standing a few yards south of the summer-house at the whirl 
pool this summer, I was impressed more than ever with what 
was taking place below me, especially in the very narrow channel 
through which the rushing torrent darts into the whirlpool. I 
regard this as one of the most interesting features connected with 
the Falls, and yet the least thought of by the thousands who 
visit the place. The gorge through which the waters rush 1s 
very narrow: I was told in 1846 by the proprietor.of the place 
that the width was only 72 yards. This I believe to be nearly 
correct, for at the suspension bridge, which is at the commence- 
ment of the rapids, and where the river is much wider, I found by 
measurement on the bridge that the width was only 118 y 
I noticed that underneath the water, a portion of rock from 
each side extends, as well as I could judge, about five yards from 
each side of the entrance into the whirlpool, reducing to sixty- 
ne within 
