582 
GEOLOGY OF THE FIRST DISTRICT. 
in boulders in almost all the southern part of the island. As we go northward the rock 
improves in quality till we reach 50th-street, and much of it is used for facings on the line of 
the aqueduct, for culverts and the various works on the island. The dock opposite Fisher’s 
glass-house is used for getting the stone to the river. On the banks of the river the strata 
are very tortuous, and the shore is rock-bound from this place to Manhattanville, with the 
exception of here and there a few rods covered with soil or sand. 
42d-street: Here we first notice the drift furrows. They are on the east side of the 
avenue. From glass-house northward two hundred yards, and fifteen yards wide, is a fine 
vein of granite, suitable for fine cutting, and in many places may be got out in cubic blocks 
of ten feet on a side. This is especially the case at 48lh-street, where it is of better quality 
than in any other place hitherto examined. The extensive bed in this neighborhood extends 
from the 10th avenue to the river, with a pretty regular descent. The gneiss on the banks of 
the river is finely exposed. The strata are full of veins of quartz and granite, g,nd are 
exceedingly tortuous. Most of the veins are parallel with the strata, but from the granite and 
quartz being protruded amidst the gneiss, has greatly disturbed its strata. 
Blasting and digging. —Blasting and removing solid rock commands from ninety to one 
hundred cents the cubic yard, and loose earth from twelve to twenty cents the cubic yard. 
Anthophyllite locality.—Yxom 48th to 58th-street, on the shore, the granite deteriorates in 
quality, and the gneiss increases in proportion, and the quality is so poor that it is not of 
much value except for filling in. About 57th-street, and extending from the 10th avenue to 
the river, the rock changes in character, and though in general character it is like gneiss, 
the material or mineral character is entirely changed ; it becomes of a soft and fibrous texture, 
fragments and boulders of Avhich are found on almost every part of the island, and called by 
the inhabitants of the city radiated asbestos. A specimen of this has been sent by Professor 
Torrey to Dr. Thompson, of Glasgow, who analyzed it and pronounced it Anthophyllite. 
This rock extends from 59th-street, following the strike, which is north 30° east; varies 
from this to due north and south as far as fi3d-street, where it dips down and disappears below 
the river. The locality of this rock is therefore bounded on the north and south by 59th and 
63d-streets, and east and west by 10th avenue and the river. The rock varies considerably 
in character in the different places where it has been uncovered, and occupies a series of 
conical hills, some five or six in number, distributed in a northerly and southerly direction. 
In some places, as at 60th-street, it is talcose in structure, and may be split into thin slabs ; 
in others, it is dark grey, almost black, composed of straight fibres arranged in a columnar 
form, meeting and crossing each other frequently at right angles. 
Another variety of this rock is that which has obtained the name of Radiated Asbestos 
rock, and the kind above referred to as analyzed by Dr. Thompson. It is generally of a 
light grey color, consisting of fibres radiating from a centre, and the radii from half an inch 
to two inches in length. 
The hills containing the anthophyllite are considerably higher than the adjoining grounds. 
The rock in the east and southeast portion of the anthophyllite locality above pointed out, is 
