BEIiKEY, GEOLOGY OF SOUTHERN MANHATTAN ISLAND 267 
b) West Pier, Blackwell’s Island. 
j Serial No. 
Original 
mark 
Location 
Depth 
to rock 
M. H. W. 
To Rock 
U. S. 
datum 
1 
Rock 
penetra¬ 
tion 
Form¬ 
ation 
Variety and remarks 
85 
1 
W. pier, S. end, 
water’s edge 
-17.3' 
-14.96' 
? 
Ford. 
Granite gneiss a light 
colored rock, similar to 
Yonkers. 
86 
Center line 
-5.0' 
-2.66' 
? 
Not found (No. 2?). 
87 
3 
W. pier N. end. 
-7.7' 
-5.36' 
? 
? 
Mica schist, usual type. 
88 
4 
W. pier, B. I. 30' 
N. E. 
-2.8' 
-.46' 
? 
Ford. 
Granitic gneiss, banded 
type. 
89 
5 
W. pier, B. I. E 
side on center line 
-9.8' 
-7.46' 
? 
Biotite gneiss, banded 
type. 
90 
6 
W. pier, B. I. 
30' S. 
—13.S' 
-11.46' 
? 
Ford. 
Mica gneiss, banded type. 
91 
• 
7 
W. pier, B. I. 
center line, water 
edge 
-8.9' 
-6.56' 
? 
Granitic gneiss. 
c) East Pier, Blackwell's Island. 
92 
1 
E. pier, S. W. 
corner 
+ 1.3' 
+ 3.64' 
? 
Ford.? 
Biotite gneiss (not char¬ 
acteristic). 
93 
E. pier, B. I. 
center line 
+ 2.5' 
+ 4.84' 
? 
Granodiorite, garnetifer- 
ous (No. 2?). 
94 
3 
E. pier, N. end 
+ 4.5' 
+ 6.84' 
? 
? 
Mica schist (not charac¬ 
teristic). 
95 
4 
E. pier, N. E. 
35' 
+ 1.1' 
+ 3.44' 
? 
Ford. 
Granitic gneiss, banded 
type. 
96 
5 
Center line E. 
side 
+ 0.7' 
+ 3.04' 
? 
Core not found. 
96 
6 
E. pier, S. E. 
35' 
-4.3' 
-1.96' 
9 
Ford. 
Granitic gneiss. 
97 
7 
E. pier, B. I. cen¬ 
ter line water’s 
edge 
-7.6' 
-5.26' 
Mica gneiss, very mica¬ 
ceous. 
d) Long Island City Pier. 
98 
1 
“ L. I. C.” pier 
-64.0' 
-61.66' 
Ford. 
Biotite schist, rotten and 
head line? or 
crushed, non-committal. 
anchorage? 
99 
2 
Not found. 
100 
3 
101 
4 
N. E. cor. an- 
-3.7' 
-1.36' 
Ford. 
Mica gneiss (schistose 
chorage? 
type). 
102 
5 
“ L. I. C.” 60' 
-22.4' 
-20.06' 
? 
Biotite hornblende schist, 
W. of pier 
streaked. Might be 
either formation. 
103 
6 
“ L. 1. C.” pier, 
-22.0' 
-19.66' 
? 
Mica gneiss very mica- 
60' S. W. of pier 
ceous. 
