METAMORPHIC ROCKS. 
461 
New-York ; that of the “ Marble quarries ” of New-RocKelle, and some other similar beds. 
Prof. Gale, who examined in detail the geology of New-York island, describes the antho- 
phyllite locality as follows ; 
“ Hydrous antliopliyllite. This rock has been familiarly known for many years in this 
vicinity, under the name of radiated asbestus rock; but was known only as a boulder found 
in considerable abundance in various parts of the city, and as far north as Fifteenth or Twen¬ 
tieth-street. Its geological place was not, however, known at that time; and as its true 
mineralogical character was somewhat doubtful. Dr. Torrey sent specimens of it to Prof. 
Thomson of Glasgow, who analyzed it and pronounced it anthophyllite ; but as it contained 
a much larger proportion of water than had usually been found in this mineral. Dr. Torrey 
proposed to prefix the term hydrous, which has been generally adopted. This rock has been 
found in place on the west side of the island, between Tenth avenue and the Hudson, and 
between Fiftyseventh-street on the south, and Sixtythird-street on the north. Here the strata 
are nearly vertical; the strike is north-northeast; the width of the bed at right angles to 
the strike varies from three to thirty rods. It commences at Fiftyseventh-street, within 
thirty or forty feet of the avenue, and runs obliquely to the streets crossing the Eleventh 
avenue near Sixtieth-street, and runs out at the river on Sixtythird-street. It is remarkable 
that the granite lying on the west, and the gneiss on the east of the rock in question, come in 
complete contact with it without intermixing. So remarkable is the line of separation on the 
side next to the gneiss, where there is the best opportunity to examine the two, that within the 
space of three inches each rock possesses all of its own peculiarities, with none of those of its 
neighbor. The mineral character of this rock varies much in different parts of the bed. In 
the southeast portion, where it. approaches nearest to Tenth avenue, it exhibits little or no 
stratification, is very dark colored, and has a tabular structure. In the same vicinity are found 
masses of serpentine and limestone intermixed, exhibiting a porphyritic appearance, the 
serpentine appearing green, and the limestone white. Again, near the middle of its course, 
or near where it crosses the Eleventh avenue, it becomes lighter in color, more fibrous and 
scopiform in structure ; but the fibres are large, and in some instances approach the character 
of actynolite. Still lower down, following the strike towards the river, the same mineral 
character continues, except that the fibres are still finer, and the whole texture becomes softer 
and more like steatite ; so that many years ago, before the rock was known to geologists, it 
was attempted to work this bed for a soapstone quarry, to be applied for similar useful pur¬ 
poses ; but the material being too hard, the project failed.”* 
Another locality of serpentine rock, with radiating fibres of anthophyllite ? occurs in a 
southeasterly direction from Whiteplains three or four miles. I did not see it, but was in¬ 
formed of it after I had left that part of the country. I had inferred the existence of such a 
locality, from the boulders of this rock which I saw scattered over the fields. Another loca¬ 
lity is in Philipstown, Putnam county, about ten or eleven miles north-northeast of Peekskill, 
* Prof. Gale’s Report on the Geology of New-York Island, in the Third Annual Report of New-York, 1839, p. 193. 
