DRIFT DIVISION. 
181 
of the village of Manhattanville, and at the southwest corner of a Mr. Stevens’ house, between 
it and the road. The whole rock on which it rests is covered with diluvial grooves; and a 
very large one three inches deep and eighteen wide, between the road and the boulder, and 
terminating at the latter, seems to have been the result of the movement of this huge mass. 
Specimens are in the State Museum. 
6. Hydrous anthophyllite. This rock has been familiarly known for many years in this 
vicinity under the name of radiated asbestos 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 Twentieth- 
street. Its geological place was not, however, known at that time ; and as its true mineralo- 
gical character was somewhat doubtful. Dr. Torrey sent specimens of it to Professor Thomson 
of Glasgow, who analyzed 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 Fifty-seventh-street on the south, and Sixty-third-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 Fifty-seventh-street, 
within thirty or forty feet of the avenue,'and runs obliquely to the streets, crossing the 
Eleventh avenue near Si.xtieth-street, and runs out at the river on Sixty-third-street. It is 
remarkable that the granite lying on the west, and the gneiss on the east of the rock in ques¬ 
tion, come in complete contact with it without intermixing. So remarkable is the line of sepa¬ 
ration 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 porphy- 
ritic 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 
colour, 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 firmer, 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 purposes ; but the material being too hard, the project failed. 
This rock has been found in boulders in all of the southern part of the island, and some 
are very large. On the west side they extend from the rock in place to Fifteenth-street. In 
the middle division they have been found from Forty-eighth-street on the north to Fourteenth- 
street on the south, and on the east side from Twenty-fourth-street to Corlear’s hook. 
On the south side of Fourteenth-street, between Bowery and Third avenue, is a boulder 
of this rock fifteen feet long, twelve broad, and six high, containing on its surface abundance 
