ALLUVIAL DIVISION. 
89 
carburetted hydrogen, nitrogen, sulphur, naphtha and petroleum. Some of these, and others 
not mentioned, that are of little geological importance, are valuable in a medicinal point of 
view, and for yielding substances of value in the arts. 
Carbonic acid is one of the most common substances in mineral waters. It is a well esta¬ 
blished chemical fact, that carbonates are soluble in an excess of carbonic acid. As spring 
waters containing carbonic acid flow along the Assures of limestone, the carbonic acid is con¬ 
tinually exerting its solvent action upon the rock, and transporting the dissolved carbonate of 
lime to distant parts. This offers a ready and satisfactory explanation of the numerous exten¬ 
sive caverns in limestone districts, to which they are almost exclusively confined. 
Water will retain only its volume of carbonic acid at the common atmospheric pressure; 
but by increasing the pressure, more will be absorbed in proportion to the force employed. 
The effect of this is seen in many mineral springs, where the water sparkles by the extrication 
of bubbles of the gas, as the pressure is relieved by the water issuing from the spring. If 
such waters contain a carbonate of slight solubility, it is deposited in proportion as the car¬ 
bonic acid gas escapes. Such has been the effect at the High-rock spring at Saratoga, the 
Sharon springs, Lebanon springs, and many others that might be mentioned. 
Chalybeate Springs. 
Chalybeate waters contain carbonate of iron, held in solution by carbonic acid; and the 
adjoining valleys and marshes into which such springs flow, always contain bog iron ore, or 
soil stained by limonite, unless they flow into a stream so as to prevent a deposition of the 
ferruginous matter. 
The following localities have been examined during the progress of the Geological Survey, 
where chalybeate water flows from the earth. 
Near Upton’s pond in Stanford, Dutchess county. Prof. Merrick examined a small chaly¬ 
beate spring, from which an unusual quantity of iron ore was deposited. 
Near the village of the Brick-yard Shakers in New-Lebanon, Columbia county. Prof. 
Briggs examined the water of a spring highly charged with iron, and iron ore was deposited 
in small quantities. 
Two miles south of the above village, the same observer saw a similar spring near the 
road; and in several places near the road, south of Mr. Bailey’s in New-Lebanon, a reddish 
deposit was made by the spring waters. He also observed ferruginous matter deposited from 
water near Mr. Grant’s in New-Lebanon, on the east side of the valley, and three quarters of 
a mile from the turnpike road. 
A small chalybeate spring was seen on the east side of the road, half a mile south of 
Canaan centre, Columbia county; another two miles northeast of the Lutheran church in 
Milan, Columbia county, on the land of John 1. Link. 
A chalybeate spring was seen on the west side of the road that leads up the left bank of 
the Susquehannah, between Sidney plains and Unadilla, and another between Unadilla and 
Franklin, both in Delaware county. 
Geol. 1st Dist. 
12 
