SURVEY OF THE ISLAND OF NEW YORK. 
597 
The gneiss at 22d-street rises from five to twenty feet above the surface of grading, and is 
one hundred and forty feet north and south, and eighty feet east and west. Strike N 35° E. 
Well characterized gneiss. I>ip 75° to 80° W. 
Drift grooves covering almost the whole rock. Direction N 25° W. Depth one-tenth to 
three-quarters of an inch ; width, half an inch to fifteen inches. It is remarkable that cross 
seanas of granite, cutting tlie gneiss across the strata, extend from one extreme of the rock 
to the other, as seen in the sketch (PI. 37, fig. 1). 
The portion of the rock above grading, extends from 21st to 24th-street, and from 1st to 
2d avenue. The- drift scratches are more distinct at the northern extremity, near the middle 
division of the Bellevue hospital yard. Here the grooves are from an inch to an inch and a 
half deep, and from one inch to twelve inches wide. Direction as before. The whole rock 
is abundant in veins of granite, but they are generally narrow. 
On 24th-street, and opposite Bellevue yard^ the drift being removed so as to uncover the 
rock, the latter is found to be of a soft, unctuous substance, and exhibiting three varieties : 
1st. Nearly white, and containing much mica; quite as soft as the softest talc. 
2d. Somewhat softer than the last, unctuous to the feeling, containing abundance of mica 
of a bright red, like the deepest peroxide of iron or dark jasper. 
3d. Less soft than either of the preceding, and appears like a decomposing or disintegrating 
gneiss, from decomposition of the felspar contained. 
27th and 28lh-streets : The rock is a fissile and decomposing or disintegrating gneiss ; 
appears along the northern end of Bellevue enclosures, about twenty feet above grading, and 
extends to the v/aters of the East river, where it is twenty-five or thirty feet above, and con¬ 
tinues northward to Kipp’s bay, with but little variation in character. Strike N 35°' E. Dip 
varies widely in a few hundred feet (being west) from 50° to 80°. 
Kipp’s Bay .—This bay commences at about 30th-street, and extends northward to 38th or 
40th-street. Here the river forms an indentation into the land as far as to 1st avenue by 35th- 
street, where the rock is a sound and finely stratified gneiss, with few veins. Strike N 30° 
E. Dip W 45°. The whole rock is covered with drift grooves ; they are large and shallow. 
Some are firom twelve to eighteen inches broad, and from half an inch to an inch and a half 
deep. This rock is now being removed for building purposes in the city. 
Near the glass house, but southwest of it, the gneiss appears above the surface covered 
with grooves N 30° W, half way between 1st and 2d avenue. 
Here also a boulder of greenstone thirteen feet long, seven broad and six high j worn very 
much—smooth. 
Elisha Mott's Quarry .—About 37th-street the land extends again eastward, and the rock 
rises some sixty or eighty feet above tide-water, and continues at or near the same height to 
the shot-tower, though it occasionally dips down below it. 
Near 37th-street and 1st avenue is the New-England glasshouse ; further east, on the banks, 
is a large gneiss quarry, recently worked by Mr. Elisha Mott, but now abandoned. Strike 
N 45° E. Dip W 45° to 50°. It is a compact and good gneiss for rough work in building. 
