ALLUVIAL DIVISION. 
107 
Haverstraw Gas Spring. 
This is in the township of Haverstraw, Rockland county, about two and a half miles south¬ 
west from Stony point, by the side of the road leading from Caldwell’s landing to Haver¬ 
straw, on the land of Mr. Alexander Walden. It is a copious spring, a small brook flowing 
from it, and bubbles of gas are continually rising from different parts of the fountain. The 
water is used for domestic purposes ; and if it be thermal, it is very slightly above the mean 
temperature of the place. It issues from near the junction of the limestone with a talcy slate 
of the Taconic division of rocks, (which range reaches the Hudson river from the north at 
Blue Rock point, at the mouth of Peekskill creek, where the post-road bridge crosses that 
stream; and on the right bank of the Hudson, it reappears at a short distance north of 
Tompkins’lime'quarries, between Caldwell’s landing and Stony point.) Granitic rocks are 
near, both east and west; and the talcose slate and limestone both disappear in a short dis¬ 
tance to the south of the fountain, under the red sandstone formation of Rockland county. 
The cause of the evolution of nitrogen gas is not known. The theory of Longchamps has 
been adduced by Prof. Eaton as being a plausible one. M. Longchamps maintains that “ the 
oxygen and nitrogen of the air unite and form nitric acid, when in contact with calcareous 
substances which' are sufflciently porous, and under the influence of a due proportion of heat 
and moisture. As the sparry limerock is often found porous, and of a spongy texture, it may 
cause the supposed union of oxygen and nitrogen of the air, which comes in contact with it at 
a considerable depth under the detritus. Here the temperature of the water may be suitable 
for the operation. If nitric acid is produced in this manner, the following may be taken for 
the result, allowing for fractions : Nitric acid consists of 35.1 bf nitrogen to 100 of oxygen; 
atmospheric air consists of 376.2 nitrogen to 100 of oxygen; therefore every 100 of oxygen 
consumed in the production of nitric acid from atmospheric air, would produce 341.8 of 
unmixed nitrogen gas; consequently about of the nitrogen gas of the air thus decomposed 
would issue unmixed from the earth.”* If this theory be true, some trace of nitric acid, in 
some form of combination, might be expected to be observed in the waters, if they flow from 
where the decomposition is effected ; and it is not apparent how atmospheric air in such quan¬ 
tities should be carried deep into the earth, even if such changes could there be effected in its 
composition. These objections might be urged, and had much weight until the following facts 
were considered, viz: 1. Water falling in cascades or into deep pits in the ground, carries 
much air with it; so that if the aperture of entrance into a cavern in which it may fall be 
narrow, or nearly filled by the descending current, the air can not return; but if the outlet of 
the cave be open, it will form a blowing cave, that is, one with a current of air rushing from 
it; or if its outlet be under water, the air will issue with the water from its outlet, or escape 
through the fissures of the rock. 2. Nitrate of lime, we know, is formed in abundance in 
almost all limestone caves, unless they be very wet. 3. Caves are very common in limestone 
Eaton. Silliman’s Journal, Vol. 15, pp. 234, 235. 
