NIAGARA FALLS. 
393 
in Orleans county, is over the same strata, and exhibits the succession of falls and rapids, 
precisely in the manner I have just enumerated. The quantity of water, however, in this 
stream, is too small to produce any thing like a degree of recession to compare with the 
Niagara river. 
The following diagram will explain these remarks by showing the present position of the 
falls and rapids along the stream; the numbering corresponds to that upon the Niagara sec¬ 
tion, page 386: 
1. Lower part of Medina sandstone. 2. Quartzose sandstone. 3. Alternating, shaly and hard sandstone. 4 . Greyband; 
termination of the Medina sandstone. 5. Green shale of Clinton group. 6. Limestone of Clinton group. 
7. Niagara shale. 8. Niagara limestone ; falls at Shelby. 
The same views have already been explained and illustrated, in relation to the falls on 
Genesee river ; but the quartzose sandstone (No. 2) of the Niagara section does not extend 
so far eastward, and, therefore, it forms no item in the calculation at that place. The hard 
limestone layer (No. 6), or one filling the place of that at Niagara, has retreated a quarter of a 
mile farther up the river, where it forms a fall of twenty-five feet. This recession of the lime¬ 
stone, beyond the sandstone, is owing to a mass of green shale below it, twenty-three feet 
thick, while at Niagara the same shale is but four feet thick. From this place to the upper 
fall, about a mile and a half distant, we have a rapid stream. This fall is one hundred and 
ten feet high, and over precisely the same rocks as the Niagara fall at present, viz. Nos. 7 
and 8 of section, the Niagara shale and limestone. The limestone at the top of the fall is 
much thinner than that at Niagara, in consequence of the less recession into the mass, as well 
as from being thinner as a whole. We have here a case precisely analogous to Niagara, as I 
have supposed its former condition. 
Had the quantity of water flowing down the Genesee been equal to the Niagara, the 
upper fall would have been excavated farther backward, and the lower fall, in all probability, 
entirely obliterated, presenting a rapid current from the upper fall to the present site of the 
Rochester landing. There appears here positive proof that there never has been so large a 
body of water passing down the Genesee as down the Niagara, and the concurring testimony 
is to the effect that the wearing action has been far less. The recession of the lower falls at 
Rochester would add little or nothing to the height of the upper; for the ascent of the river 
bed, and the dip of the strata, would cause the disappearance of the whole beneath the water, 
before reaching that point. 
[Geol. 4th Dist.] 
50 
