34 
ROCK FLOOR OF GREATER NEW YORK. 
[BULL. 270. 
Summary of records of borings made in New York and vicinity — Continued. 
1. BORINGS BENEATH CHANNELS ON WATEB FRONT— Continued. 
Serial 
num- 
ber. 
Depth of boring to rock. 
Location. 
east rivee sections — continued. 
East River bridgt No. I— Continued. 
Blackwells Island pier, west 
bulkhead line— 
92 Boring 3 
93 
94 
95 
As given. 
Boring 7 
Boring I 
( tenter line of bridge, cast bulk- 
head line. 
3.32 
4.49 
L2.89 
1 
Referred 
to r. s. 
datum, 
Sandy 
Hook. 
East Rivt r /"/'.-." 
Man-o'-War reef Near datum 
Blackwells Island reef do 
Reef off 26th street 
3d street 
I2d street 
47th street 
Ct nit r lint of U2d street {produced). b 
East of bulkhead line — 
About 200 feet 
About 7:;n tort '.. 
Aboul L,540 tret : 
About 1,950 feet 
About 10") fret cast of 101'/ 
About middle of eastern chan- 
nel. 
Pennsylvania i;<iih<><i<i tunnel, foot of 
Flushing street, Long Island <'/ti/.i<> near 
foot. of 38d street, New York ( '////. <• 
1,750 feet cast of New York bulk- 
head line (a). 
(6) 
+ 3 
Kind of rook, if known. 
( rneiss. 
Do. 
( rneiss. 
Do. 
Do. 
Do. 
Do. 
Do. 
96 
07 
98 
99 
100 
101 
101a 
101 A 
L01c 
101,/ 
L01< 
101/ 
102 
103 
"Hydrography of East River. C S. (oast and Geodetic Survey. 
oNos. 101a-101/ records of core borings furnished by Alan A. Robbins, resident engineer, New Yo 
and Long Island Railroad. Rock of LOla-lOle, "decomposed gneiss." No. 101// is 100 feet west 
Man-o -War reef, LOlc is 400 feet east of Man-o'-War reef, LOld is midway between Man-o'-War reef a 
the east shore, and 101c is about 500 feet west of the eastern shore. Rock of 101/", " white crystalli 
dolomite." 
c Noble, A., and Jacobs, C. M., chief engineers, Pennsylvania. New York and Long Island Railro 
Company; wash borings. 
1 10 
KM 
108 
99 
< rneiss. 
108 
Do. 
108 
Do. 
88 
Do. 
88 
Do. 
94 
Do 
oinite 
106 
Rock or bowlder. 
