SILICA. 
277 
line. It is very abundant; may be obtained in large blocks, and when polished, has a per¬ 
fectly black colour, and is highly esteemed for ornamental purposes. 
In the fissures of this serpentine, there are veins of tremolite, schiller spar, and other allied 
minerals. 
At “ Cotton rock” in Phillipstown, three and a half miles below West-Point, precious ser¬ 
pentine occurs with veins of silky amianthus, whence the name of the locality. 
Richmond County. Serpentine passing into steatite, and containing veins and masses of 
magnesite, asbestus, amianthus, talc, hydrate and carbonate of magnesia, is found at the 
quarantine. Indeed it constitutes the main ridge of hills on the island, which extends from 
New-Brighton to a little west of the village of Richmond, a distance of about eight miles. 
According to Mr. Mather, this ridge ranges N. 20° E. and S. 20° W., and the prolongation 
of the line of direction strikes the serpentine hills of Hoboken in New-Jersey. Through¬ 
out its whole extent, this rock exhibits the diversified characters which are observed at the 
Quarantine, or New-Brighton. This grouping of minerals, as in other cases, renders it quite 
difficult to distinguish the several varieties from each other. There are many intermediate or 
transition states of these serpentines, which, in hand specimens, might be considered as dis¬ 
tinct ; but an attentive examination of the locality will unfold their true character, and save 
the chemist much labor and anxiety. 
Rockland County. Serpentine is found in grains and small masses in limestone, at several 
localities. Some of these have been noticed under the head of Marble (page 70). I am not 
aware that pure serpentine has been found in masses of any considerable magnitude. 
St. Lawrence County. This mineral, in almost every variety, is very abundant in this 
county. In the form of verd antique, it is found in the towns of Gouverneur, Fowler, 
Edwards and Pitcairn (see page 70); while the variety soapstone is abundant in the towns 
of Edwards and Fowler. Indeed, in most of those places where the true serpentine is found, 
it passes into the softer varieties of steatite (soapstone), or into that mixture of pyroxene and 
steatite which Dr. Emmons has called Rensselaerite. 
The crystallized variety, and the precious serpentine of a light green colour, occur in 
the immediate vicinity of the village of Gouverneur; and the same mineral in the massive 
form is found associated with calcareous spar, at Morris 5 natural dam, about two miles from 
that place. It is sometimes of a yellowish green colour. 
In the vicinity of Gouverneur, crystals are also found, which have the form of scapolite 
in several of its modifications, but which appear to consist chiefly of serpentine or steatite. 
In accordance with the general views which have been drawn from the analysis of several 
supposed pseudomorphs of hornblende, pyroxene and spinelle, it is more lhan probable that 
these crystals are composed of a portion of the constituents of scapolite, another part of which 
has been replaced by serpentine or steatite. The only change necessary for this purpose, is 
the removal of a part of the alumina and lime, and the substitution of magnesia. 
The serpentine at Gouverneur is frequently also replaced by the fibrous and radiated form 
of steatitic pyroxene, which is so frequently met with in this and in Jefferson county. 
