266 
ANNALS NEW YORK ACADEMY OF SCIENCES 
Bridge No. 4. “Blackwell’s Island Bridge,” or “Queensboro Bridge” 
The cores obtained in boring explorations for the piers of the Queensboro 
bridge are housed with those of Bridge No. 3, at the Brooklyn Terminal 
of Bridge No. 1 (old Brooklyn Bridge). The system of numbering was 
such in this case that the same numbers were in part repeated at each pier, 
and, where other designations or descriptive labels are wanting, the locations 
are therefore somewhat uncertain. Most of the boxes, however, in which 
they are stored have some mark indicating the pier represented, for example, 
“No. 4, N. Y.,” or “No. 4, W. Pier” (Blackwell’s Island), or “No. 4, East 
River” (Blackwell’s Island) or “ No. 4, N. E. cor. Anchorage” (Long Island 
City) and are therefore more definite. 
The whole series was examined, and borings have been arranged in 
groups representing the different pier locations as fully as can be done with 
the data at hand. The series as a whole gives entirely satisfactory and 
consistent evidence as to bed-rock character. The datum is M. H. W. and 
is 2.34' above mean sea level (U. S. datum) at Sandy Hook. 
a) New York Pier. 
Serial No. 
Original 
mark 
Location 
Depth 
to rock 
M. H. W. 
To Rock 
u. s. 
datum 
Rock 
penetra¬ 
tion 
Form¬ 
ation 
Variety and remarks 
75 
65' E. of bulk¬ 
head 
-51.4' 
-49.06' 
? 
Not found (No. 1?). 
76 
2 N.Y. 
40' inside of pier 
line 
-80.4' 
-78.06' 
? 
Manh. 
Typical mica schist . 
77 
3 N.Y. 
Bulkhead line 
-34.2' 
-31.S6' 
? 
“ 
“ “ “ 
78 
4 N.Y. 
35' inside bulk¬ 
head 
-4.0' 
-1.66' 
? 
79 
Pier line 
-37.9' 
-35.56' 
Not found (No. 5?). 
80 
6 N.Y. 
40' E. of bulk¬ 
head 
-45.6' 
-43.26' 
? 
Manh. 
Typical mica schist. 
SI 
7 N.Y. 
25' N. E. of N. 
pier 
-26.5' 
-24.16' 
? 
82 
8 N.Y. 
20' E. of N. pier 
-31.0' 
-28.66' 
? 
“ 
“ “ “ 
83 
9 N.Y. 
30' N. of N. pier 
+ 4.5' 
+ 6.84' 
? 
“ 
“ “ “ 
84 
10 N.Y. 
Between No. 7 
and No. 9. 
-1.7' 
+ .64' 
? 
