42 
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 WATER FRONT— Continued. 
Location. 
Depth of boring to rock. 
Kind of rock, if known. 
Serial 
num- 
ber. 
As given. 
Referred 
to U. S. 
datum, 
Sandy 
Hook. 
HARLEM RIVER FRONT AND SUC- 
TIONS — continued. 
1 
Dock line— Continued. 
Center of 154th street (pro- 
duced) — 
276 
50 Ictt east of bulkhead Hue . . . 
- 38 
- 40 
Rock or bowlder. 
277 
55 feet north of south line of 
138th street on bulkhead line. 
Washington Bridgt .<< 
- 98 
-100 
Do. 
27S 
200 feet west of west pier of west 
arch. 
60 
Gneiss. 
Low-water line, west side. 
Center pier 
East pier of east arch 
200 feet east of last.. 
High Bridge.** 
150 feet west <if west bank of river 
130 feet (aboul I east < if west hank 
river. 
Under central pier 
200 feet easl of central pier 
280 feet east of east bank of river 
.w a- aqueduct.c 
Near west shore bulkhead line — 
200 feet west 
50 feet west 
1 75 feet east 
Near east bulkhead line— 
At line 
600 feet east of lint 
750 feet east of line 
1,000 feet east of line 
25 
30 

71) 
80 
Do. 
i Gneiss, marble, ant 
\ fault rock. 
( rneiss. 
Do. 
Gneiss. 
Do. 
No rock. 
Marble or limestone 
ichist an 
gneiss. 
(Mica- 
l gneif 
Gneiss. 
Do. 
Soft rock. 
Lime rock or marble. 
Soft rock. 
Do. 
Lime rock or marble. 
a Hutton, W. R., chief engineer, " The Washington Bridge," New York. 1890, p. 21, pi. 2. 
?> Church, B. S., resident engineer, quoted by Dana, .1. I>.. Am. .lour. Sci., 3d ser.. vol. 21. p. 435. 
cRept. New York aqueduct commission, 1887 L895, p. 88, sheet 32. No. 292 had 20 feet and No. 293' 
had 4U feet of "lime rock or marble." 
