BLACK RIVER LIMESTONE. 
45 
west. The layers of this quarry are more numerous, and the accretions also more abundant 
than in the other three quarries. The mineral nature of the birdseye is obvious in the mass. 
The fossils noticed in this quarry were a strophomena; a large ramose form, supposed to be 
a polyparia, and which exists in the same position at Glen’s-Falls ; also Cyathophyllum cera- 
tites ? etc.; all which will be further noticed by the Palaeontologist. 
The same limestone occurs at Humphrey’s quarry, on the south side of the river between 
Fulton and the Noses, and in the neighborhood of Amsterdam. 
The Birdseye limestone is not confined to New-York. It is a rock in the geological sense. 
It forms the surface of Nippenose valley in Pennsylvania. It is the marble of Frankfort, 
Kentucky, forming there a cliff about thirty feet thick, and of a light bluish cream-color. Its 
layers are very regular, and formed by a slight accumulation of shale. Its fracture is like that 
of the birdseye of New-York, and it contains white crystalline particles such as exist when 
the F. demissus is replaced by this mineral. Above it, in places, are high bluffs composed of 
light-colored shale, and very thin interrupted layers of limestone, loaded with fossils, many of 
which are the same with those which characterize the Trenton limestone, and others have no 
analogy with those of any other known rock. The same masses exist in the bluff at Nash¬ 
ville, Tennessee; but the birdseye is of a brownish color, and in thin layers, the rock proba¬ 
bly coming to an end in that direction. 
4. TRENTON LIMESTONE. 
Metalliferous Limerocli of Eaton. 
(No. 2. Pennsylvania Survey.) 
This rock takes its name from the falls on West Canada creek, and the falls from the town 
of Trenton in Oneida county; in which, or by the side of which these rocks are placed, the 
line between Herkimer and Oneida passing in this direction. At Trenton falls, there are two 
distinct varieties: The first is a dark or black-colored fine-grained limestone in thin layers, 
separated by black shale or slate, and which forms the great mass through which the creek 
has worn its channel, and in which are all the falls ; the second is a grey coarse-grained lime¬ 
stone in thick layers, which forms the top of the mass. Fossils are extremely numerous in 
the dark-colored part, but are less numerous in the upper or grey part: this latter kind is 
quite crystalline. 
The Trenton limestone is extremely well characterized, especially by its fossils, a number 
of which are peculiar to the rock ; and though others reappear in one or more subsequent 
ones, they offer no difficulty in the recognition of this limestone, because there is not only a 
