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CHAMPLAIN DIVISION. 
Before I pass to the consideration of the succeeding members of this group, I desire to 
call the attention of geologists to a narrow and irregular belt of the Calciferous sandstone 
which extends from Greenbush to the Canada line. It is apparently fragmentary, and is 
in some places undoubtedly so. It is fossiliferous, but most of the fossils are mere frag¬ 
ments, consisting of pieces of the crust of the Illenus and Isotelus ; but among tlxese 
fragments, some small specimens of crustaceans may be seen, nearly perfect. 
This mass is very liable to be confounded with the Sparry limestone, inasmuch as it is 
traversed by veins of calc-spar ; and where the soil conceals its borders, it is apparently 
interlaminated with the Taconic slate ; yet in many places it may be taken off' from the 
upturned edges of the slate, and is absolutely and entirely removed from these where it 
has been quarried in several localities. This shows plainly, then, that it is a rock of an¬ 
other age, from the slates upon which it rests; and as this rock is broken up, and as into 
it we find there has been introduced peculiar fossils, it shows that there was a change, a 
beginning of a new era, which we may with great propriety consider as the commence¬ 
ment of a new system. 
§3. ClIAZY LIMESTONE. 
Notwithstanding the remark that the lower limestones of the Champlain division may, 
with at least a show of propriety, be placed under one name ; still it is right, in our esti¬ 
mation, to designate certain masses under local names, where they are found in thick beds. 
This especially seems right in the case of this limestone, which exists in Clinton county, 
and whose entire thickness is at least one hundred and thirty feet. At Chazy, it is a dark 
durable limestone, more or less cherty and thick-bedded ; but so little disposed to split in 
any direction, that it is quarried with difficulty. This limestone is quite limited : it is best 
developed at Chazy, but still may be observed at Essex, where the characteristic fossil, the 
Maclurea , is quite abundant. 
§ 4. Birdseye limestone. 
This is the only perfectly compact limestone which occurs in the Champlain division. 
It breaks with a conchoidal fracture. The color is a light drab, passing into a dark blue. 
The light-colored variety has been pronounced a good lithographic stone. At Chazy, it is 
intei laminated with a few beds of fine granular siliceous limestone, similar to the hydraulic 
variety in the Calciferous sandstone. This variety is the most important for making quick¬ 
lime ; for although it is often quite dark-colored, still it forms a remarkably pure white lime, 
and well adapted for glass-making, and for any of those arts where a pure lime is required. 
Such are some of the beds at Chazy. Some of the beds are singularly filled with calca¬ 
reous spar : it often replaces the curious fossil hitherto known as the Fucoides demissus, 
but which (as will be seen by reference to my report) is strictly a polyparia. This is con¬ 
sidered the characteristic fossil; though near its junction with the next mass of limestone, 
several fossils allied to those in the Trenton limestone are somewhat abundant. The 
Orthoceras multicameratus is, however, equally characteristic with the Fucoides demissus. 
