SURVEY OF THE ISLAND OF NEW-YORK. 595 
the island projects eastward very considerably, so as to require the laying out of Avenue A, 
possibly B, at a future day. 
Between 49th and 50th-street, ten rods east and one rod west of the avenue, remarkable 
grooves in each, the strike is N 30° E. Dip 45° W, and the grooves N 25° W. 
47th-street, thirty rods east of 3d avenue. Grooves N 25° W. Dip W 75°. Strike 
N 30° E. 
Most of the soil from 3d avenue to the East river is loam, gravel or sand; the gneiss 
appearing in only a few points, except on the shore. Boulders of granite, greenstone and 
sandstone, and occasionally white limestone, like that at Kingsbridge. The surface east of 
Yorkville is undulating, with many conical hills of gravel and sands. 
79th to 44th-street: The country is undulating gentle hills and valleys. The gneiss gene¬ 
rally appearing on the summits, but of an inferior quality; the strike averaging N 25° E, 
and the dip varying from 45° W through the vertical to 45° E, but generally vertical or 
near it. The rock is generally destitute of any veins of magnitude, and unfit for uses in 
building, except for filling in docks or streets. 
43d-street: Grooves on both sides of the avenue. Direction 25° W. Dip 75° W. 
Strike N 30° E. 
44th to 42d-street: Opposite 44th-street the gneiss appears on east side, ascending seventy 
or eighty feet in two hundred feet distance, and then sinks down ; dips below surface as we 
go towards the East river. Strike N 45° E. Dip 35° to 40° W. The rock extends to 
42d-street. 
42d to 36th-street; Valley. 
35th to 34th-street: Gneiss on east side. Strike N 45° E. Dip 45° W. 
34th to 29th-street: Filled in most of the distance. 
29th to 24th-street, and so on to 18th-street, has been graded, and none of the rock appears 
in place, except one or two instances, where it was reached in excavations for w.ells and 
cellars. 
18th to 8th-street: The rock does not appear at the surface, but has been frequently reached 
at the depth of ten to fifteen feet below grading, but I have not been able to get the strike 
and dip in these cases. 
Between 32d and 14th streets and 3d and 4th avenues, or on Lexington avenue : A consi¬ 
derable portion of this plot of ground remains at present unoccupied, and was originally, for 
a considerable part of the way, covered to ten or fifteen feet deep above grading with drift 
loam, pebbles and boulders, some of the latter of which were of immense magnitude. 
26th to 30th-street: Where the soil has been cut down about four or six feet to grading, 
the whole surface seems almost completely covered with the boulders it contained, two-thirds 
of which at least are greenstone, the remainder being granite with a few exceptions. The 
greenstone were almost universally worn, rounded and polished, while the granite were as 
generally angular and rough. This circumstance was very strongly marked over the whole 
space. 
