596 
GEOLOGY OF T«E FIRST DISTRICT. 
On the 3d avenue, west side, and a few feet (say thirty) south side of 16th-street, is a 
boulder of hydrous anthophyllite, thirteeji feet long, eight feet in breadth, and seven in height. 
It is very uniform in texture, and is covered with drift scratches running generally with the 
largest diameter. 
On the southern side of 14th-street, between Broadway and 3d avenue, is another boulder 
of hydrous anthophyllite, fifteen feet long, twelve feet in breadth and six in height, containing 
on its surface drift scratches parallel wdth the largest diameter. 
The above are the largest bouldei-s of this rock hitherto found on the island ; but they have 
been found from Corlear’s hook, on the southeast extremity of the island, to as high up as 
50th-street on the Bloomingdale road, on the east side of the island, and on the west side from 
13th-street on the south to 24th-street on the north. 
Section lying between 3d avenue and the river and 2d-street on the south, and 21st-street 
on the north : Commencing the southern part of the section, we find from 1st avenue on the 
west and 2d-street on the south, to Avenue C on the east, and indefinitely on the north, is 
chiefly waste or tilled grounds, graded from six to ten feet above the natural surface. Above 
lOth-street, however, the waste grounds extend westward to near the 3d avenue. 
From 5th-street northward, the above square, as far west as Avenue A, below lOth-street, 
are the remains of the old Stuyvesant meadows, and as the streets are filled in, the lots are 
mostly covered with water, and still exhibit remains of the old meadow grass. 
The salt marshes which covered the grounds in this vicinity extended westward as far as to 
the middle of Tompkins square, which is between Avenues A and B, and thence northward 
at an angle of 45° with the streets crossing Avenue A at lOth-street and 1st avenue at 14th- 
street, as will be -seen on inspecting the map of the salt marshes (Vide PI. 1, fig. 2). 
From 12th-street to 20lh or 21st-street, and from Avenue A on the east to 3d avenue on the 
west, is mostly filled in to grade level on the line of the streets, but many of the l6ts remain 
at the old level four to eight feet below. There are still remains of drift hills to be seen ; one 
extending from near Burnt-mill point, or the junction of Avenue D and 13th-street, and 
running nearly parallel with the street, extends some blocks westward. Another commences 
near Avenue A, between 15th and 16th-streets, and extends westward and northwestward 
until it joins 3d avenue from 17lh to 19th-streets, having salt marshes both north and south 
of it; north to 21st-street, and south to 5th-street. First appearance of gneiss east side. 
16th-street: Corner of 2d avenue, east side, strike N 40° E ; dip W 80° ; drift grooves 
N 25° W. Corner of 3d avenue, east side, strike 35° E ; dip W 80°. Corner 4th avenue, 
east side, strike N 25° E; dip W 80°. 17th-street, one hundred feet west of 3d avenue, 
within five feet of surface. 
Second Avenue. 
Bellevue .—At 22d-street, near 1st avenue, the gneiss first appears above the surface as we 
go northward. The grading for streets has here laid bare a large amount of boulders, of 
which more than one half are greenstone. These are exceedingly abundant for three or four 
blocks northward. 
