SURVEY OF THE ISLAND OF NEW-YORK. 
581 
(G). DIARY OF A GEOLOGICAL SURVEY OF THE ISLAND OF NEW-YORK, BY 
L. D. GALE, M. D. 
In describing the rocks of the island of New-York, page 518, a regret was expressed that 
Prof. Gale had not communicated his detailed observations on that island, so as to enable the 
reader to visit interesting localities. I have since found his diary of observations, and it is 
herewith subjoined. 
On Tenth Avenue.* 
August 24, 1838.—Commenced the survey of the island on the west side, beginning at the 
corner of the 10th avenue and 14th-street. This is near the northern limits of the popu¬ 
lated or populous portions of the city, on the west side, and is chiefly made grounds by filling 
in on the river banks, and occupied only on the east side. 
16th-street: Natural ground and lots covered on both sides with buildings, and so con¬ 
tinues to Chelsea square, or 20th and 21st-streets. 
In 24th-street is a boulder of asbestos rock, of four or five feet diameter; the soil hitherto, 
gravel and sand. Boulders are greenstone, granite and sandstone, with here and there 
other kinds, as the asbestos rock (that is, the Hydrous Anthophyllite of Torrey). From 
24th-street northward it is mostly unsettled, but here and there a house or hut. 
In 25th-street, and right of the avenue, is a boulder of sandstone nine feet long, five feet 
wide and seven feet high, coarse grained, or the size of a pea, well stratified. 
31st-street: Here the gneiss first makes its appearance, and on the east side, then on the 
west a few rods higher up. Strike north and south ; dip vertical. Tortuous, with veins of 
quartz six to twelve inches wide, and veins of granite from one to fifty feet, and from that to 
seventy-five feet wide, and continuous from two hundred to three hundred feet north and 
south ; and extends somewhat above the surface, filled with cross veins of quartz running in 
every direction, and easily broken out with crowbars. The granite is of rather indifferent 
quality and coarse texture, containing much felspar, coarse crystals. 
32d to 33d-streets, or opposite the New-York chemical works, and from this point to the 
northward as far as to 50th-street, the granitic veins are so abundant as to constitute the 
largest portion of the rock in many places. 
In many places the gneiss is worn away, and the granite projects many inches above: a 
good hint for builders in selecting stone to resist the action of the elements. The granite of 
this vicinity, in general, is not of a quality that will answer for facing in fine work. It 
extends from the 10th avenue to the waters of the Hudson, but dips below the surface in 
many places in the intermediate space. It is to appearance the same material as that found 
* Manuscript Geological Notes of the Survey of the First District, Vol. viii, part ii, p. 1, et seq. 
