NIAGARA GROUP. 
97 
vestigation. At this place, its characters are intermediate between those in Wayne county 
and Niagara. In the towns of Ogden and Sweden, the limestone presents some interesting 
features not observed at Rochester. In the towns of Clarendon and Barre, and at Shelby 
falls, as well as at many other localities in Orleans county, there are good opportunities for 
investigating the rocks of this group. 
The vicinity of Lockport will give the geologist, or the student, all desirable information 
regarding this interesting group of rocks; but he must still visit Niagara, to see them in the 
locality which will be remembered and known for many thousands of years. The rocks of 
the Niagara group are exhibited along the whole of the immense gorge or chasm of seven 
miles below the Falls; at first near Lewiston forming about one hundred feet of the upper 
part, and at the Falls being all that is visible above the river below. 
The section of the Niagara river from Lewiston to the Falls (Plate 3), is a transcript of the 
eastern bank as seen from the Canada shore, and exhibits the order of arrangement among 
the strata in a perfect manner. At the brow of the terrace above Lewiston, the shale of this 
group is seen to succeed the Clinton group, and is capped with a few feet of limestone. 
Thence it dips gradually southward, the limestone increasing in thickness all the distance to 
the Falls, where the shale, from being two hundred feet above the water as at Lewiston, has 
approached to within a few feet of it. The river descends in this distance about one hundred 
feet; and the level is continued in the section from Lewiston, showing this depth of water 
below the Falls. 
The same order of succession is exhibited at Niagara Falls as at Lockport; and by de¬ 
scending the staircase to the ferry, or at Goat island, the character of the strata may be seen 
as far as the shale. The upper part of the limestone, however, is not there visible, the highest 
seen being the dark brown mass below the upper one. The terminal portion of the rock is 
seen nearly a mile east, at Porter’s quarry. 
Thickness. — The thickness of the shale of this group suffers little variation throughout the 
district. At Wolcott, its thickness, by estimation, is little less than one hundred feet; at 
Rochester, it is of about the same thickness ; at Lockport, it is eighty-one feet by actual 
measurement; and at Niagara Falls, and along the river, it preserves the same, not varying 
more than one or two feet. The limestone is apparently not more than thirty or forty feet 
thick in Wayne county, but gradually increases westward, being about seventy or eighty feet 
at Rochester, and one hundred and sixty-four feet at Niagara Falls. This thickness at Nia¬ 
gara is obtained by measuring the perpendicular bank at the Falls, and levelling from thence 
to Porter’s quarry, nearly a mile east of this point, where the higher strata are seen. 
[Geol. 4th List.] 
13 
