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[Assembly 
stoncj and in the green shale of the protean group. Other fossils are 
extremely rare in this limestone. 
Along the area where this rock is exposed, there is evidence of seve- 
ral downheaves; probably caused by the solution and removal of the 
soft rocks below. These downheaves are connected with, or produced 
by the same cause as those more important ones on the east side of 
Cayuga lake, described by Mr. Vanuxem. No manifestation of dis- 
turbance appears on the sirrface; the limestone is scarcely raised above 
the level of the surrounding country, and the strata -observed in the 
quarries all dip south at an angle of from 4° to 6°. Noting the amount 
of dip in these rocks, and finding them to occm- frequently for a distance 
of several miles, we might, at first view, be disposed to estimate it as of 
great thickness. But in each of these quarries we find precisely the 
same rocks repeated, and the whole apparent thickness consists of a 
few strata which have been several times broken up. In going south 
we pass over the northern edges of strata which have been successively 
raised to the surface, while the intermediate spaces which would exhi- 
bit the faults, are filled with alluvium. 
In one of these faults arises a copious spring of pure cold water, from 
the bed of which and over an area of twenty feet, nitrogen gas is abun- 
dantly emitted. The force of the water is so great that the whole pool 
is kept in violent ebulition, which with the constant escape of the gas gives 
it the appearance of a boiling cauldron. No deposit of any kind is left by 
the water, which through its whole course to the lake is remarkably 
clear and limpid. The water from this spring, and another similar, but 
much smaller one, near, supplies the Canoga flouring mills, a saw mill 
and some other machinery. From no other spring in this part of the 
State is nitrogen gas known to issue; all others known in the State be- 
ing near the junction of transition w^ith primitive or metamorphic rocks. 
Should it be proved, as Dr. Daubeny has conjectured, that the produc- 
tion of nitrogen is due to the proximity of melted or highly heated ma- 
terials, it will be some evidence in favor of attributing the faults in ques- 
tion to subterranean or igneous action. Nitrogen has generally been 
found accompanying the waters of thermal springs, which fact may give 
plausibility to this theory; but in the springs of Chateaugay,* where ni- 
trogen issues abundantly, the water is cold, (about 40° Fahr. in sum- 
mer.) The water of the Canoga spring is probably about the same tem- 
perature. 
* Geological Report of 1837. 
