584 
GEOLOGY OF THE FIRST DISTRICT. 
63d to lOlst-street: As the survey of the 10th avenue extended north only to 63d-street, 
in purs.uing a northerly course we leave the 9th avenue, which is open only to 48th-street, 
and take the 10th avenue and that portion between it and the Hudson. 
63d to 64th-street, and from 9th avenue to 10th, the gneiss is seen in place. Strike N 10° 
W, and dip vertical. 
lOih avenue is at 63d-street gneiss, regularly stratified, abounding in veins of granite. 
Strike N 30° E. Dip W 80°. 
64th to 66th-street: Valley partly filled up ; boulders sandstone, greenstone and antho- 
phyllite rock. 
67th-street: Gneiss in place. Strike N 30° E. Dip vertical, contorted and confused, from 
the intrusion of granite veins. 
68th to 69th-street: Strike N and S. Dip W 80°. Here the gneiss is loose and tender, 
full of granite veins, decomposing and falling to sand. 
70th-street: The rock has been uncovered, and exhibits distinct drift grooves and scratches 
in abundance. Direction of furrows N 35° W. Strike N 30° E. Dip vertical. This is in 
front of A. Dailey junior’s hotel, in the village of Bloomingdale. 
Again from 10th to 11th avenue, on 70th-street, the gneiss has strike N 35° E, traversed 
by veins of granite. 
70th-street, from 11th avenue to river. Strike N 10° E. Dip W 85° to 90°. 
Here we leave the avenue as such, and take up the west side of the island, from Bloom¬ 
ingdale road to the Hudson, and from 70th-street on the south, to lOlst-street on the north, 
following the banks of the river in a northerly direction, and returning by the Bloomingdale 
road ; and as the streets cannot always be found on the river side, we shall give only approxi¬ 
mations, with a note of interrogation, at each, where they cannot be definitely pointed out. 
On the banks of the Hudson, at 70th-street, the gneiss with granite veins is abundant. Strike 
N 30° E. Dip vertical. Veins three to ten feet thick, and quartz veins from one to four 
feet thick, often separated by thin films of mica. As we go north and opposite the Asylum 
for the orphans, the rock is more purely gneiss. Dip vertical, and strike as last. 
75th-street: Strike N 30° E. Dip vertical. 
77th-street: Strike and dip same as 75th-street. Abounding in quartz veins and strewed 
with boulders of greenstone, quite angular and rough ; and drift scratches, N 40° W; 
numerous, and e.xtending almost every where in favorable situations, into the river even below 
the lowest tide-water marks, and again to the highest elevations on the island. Here the 
strike of the gneiss is N 20° E, and the dip vertical. Given direction of the grooves N 30° 
W. Surface covered by grooves from thirty to forty feet east and west, and twenty to thirty 
north and south. 
A little sketch of the vicinity is given, with the direction of the drift scratches here referred 
to. (Vide PI. 37, fig. 2.) It is in the opening, or cleared lands, lying on the Bloomingdale 
road, between Bloomingdale village and Manhattanville, and but a few rods north of the public 
house known as Burnhani’s hotel, and extending from the road to the river. 
At the quarry, opposite Burnham’s, the rock, which is gneiss, has a dip of 50° to 80° 
