80 
GEOLOGY OF THE FIRST DISTRICT. 
the woody fibre of plants as they decay, so as to represent the organic structure, although the 
organic substance has disappeared. 
The calcareous matter is sometimes deposited so as to invest and coat over irregular sur¬ 
faces of rocks, earth, or whatever it comes in contact with, like a coat of plaster; and all the 
successive layers deposited are superposed in parallel layers over the first one. 
The imitative forms of these calcareous alluvions are very numerous ; some are like hanging 
drapery and icicles, and called stalactites, which are formed in caves, or wherever water drips 
from particular lines or points, and containing mineral matter in solution which is more or less 
deposited from the dripping water; some are irregular, tuberculated masses, or like groups 
of warts or mushrooms; some are mammillary or botryoidal in form; and sometimes the 
deposition is porous and spongy in its texture, and fs then called tufa and sinter; and some¬ 
times like loose earth, and then called tufaceous marl. The stalagmites form on the floor of 
caverns or other places of deposition, instead of hanging from the roof like stalactites, and both 
are sometimes so pure and crystalline as to be strongly translucent. Those of Ball’s cave, 
in Schoharie, are among the most beautiful I have ever seen; resembling in translucency, 
color and delicacy, the finest bleached wax or spermaceti. Mr. J. Bonny, and the Messrs. 
Gebhard, of Schoharie, have many fine specimens ; and in the collection of John Gebhard 
senior, may be seen a stalagmite from that cave, of the weight of two hundred pounds or 
more, which excels any thing of the kind for its beauty that I have ever seen. Stalagmites are 
sometimes used for ornamental marbles ; and those of Ball’s cave, could they be procured of 
sufiicient size, would be highly prized for this purpose. 
Calcareous tufa, in an earthy form, occurs on the road from Schoharie to Cobleskill, a 
short distance up the hill from the Schoharie bridge. A limestone spring had its outlet at this 
place many years ago, and a large body of this tufa or tufaceous marl was deposited. The 
spring, or another similar in size, now flows from another place in the vicinity. 
Another locality is near the sulphate of baryta locality in Carlisle, in Schoharie county, 
half a mile north of Grosvenorville, where a copious limestone spring flows from the junction 
of the water limestone series with underlying slate rock. 
Another locality, and the most interesting one known in Schoharie county, is at Sharon 
springs. Here is a mass of tufa averaging two hundred yards in length, fifty yards in breadth 
and ten in thickness, probably containing at least one hundred thousand cubic yards of rock, 
formed entirely by deposition from the waters of these springs. In some parts of this mass, 
sulphate of lime and sulphur are found. The shells of helices are found rather abundantly 
in some parts of the mass, and the perfect impressions of the leaves of the beech, some spe¬ 
cies of oak, of the maple, the birch (white and black), and many other of our forest trees, can 
be easily procured. The tufa is a firm compact stone in many parts of this deposit; in others 
it is soft, spongy or slaty. Moss and twigs are incrusted in some localities on this deposit, 
and make beautiful specimens. The tufa is variously colored; white, brown, red, etc., 
according to the purity of the water, or the intermixture of organic or inorganic matter. 
Many localities might be mentioned, where smaller deposits of tufa were observed in Scho¬ 
harie county, but the above are the most important. 
