FOUNDATIONS OF TALL BUILDINGS. 
53 
Summary of records of borings made in New York and vicinity— Continued. 
2. BORINGS IN THE BOROUGH OF MANHATTAN-Continued. 
Serial 
num- 
ber. 
Location. 
Depth of boring to rock. 
As given. 
Referred 
to U.S. 
datum, 
Sandj 
Hook. 
Kind of rock, 
if known. 
Foundations of tall buihlinys — Cont'd. 
551 
American Exchange National 
Bank, Broadway and Cedar 
street." 
70 
-33 
Rock. 
552 
Exchange court building, 52-56 
Broadway. b 
-16 
No rock. 
553 
Manhattan Life building, 64-68 
Broadway, between Exchange 
place and Wall street. e 
- 43 
- 9 
Gneiss. 
554 
American Surety building, 
Broadway and Pine street. a 
- 68 
-30 
Do. 
555 
R. G. Dun building, northeast 
corner Broadway and Reade 
streets. e 
-105 
—83 
Rock. 
556 
Meyer-Jonassen building, Broad- 
way and 12th street./ 
25 to -55 
19 to -11 
Mica-schist. 
557 
Decker building, northwest cor- 
ner 16th street and Union 
square. 
15 
26 
Rock. 
558 
Warehouse building, 6 east 18th 
street, near Fifth avenue. h 
37 
3 
No rock. 
559 
Flatiron building, 22d to 23d 
streets, between Fifth avenue 
and Broadway. * 
35 
Rock. 
560 
Siegel-Cooper building, Sixth 
avenue, 18th to 19th streets. J 
16 to -28 
17 to - 5 
Do. 
561 
Hospital, Second avenue, 17th to 
18th streets.* 
22.5 

Do. 
562 
Y. M. C. A. building, 23d and 
24th streets and Fourth ave- 
nue. 1 
4 to -16 
17 to -29 
Gneiss. 
563 
Court of Appeals building, Madi- 
son avenue and 25th street. m 
7.2 
29 
Do. 
a Engineering Record, vol. 40, 1899, p. 463. " Rock or hardpan." 
b Idem, vol. 38. 1898, pp. 35-36. Pile's driven 50 feet. 
cGratacap, L. P., Geol. City of New York, pp. 10-12; about 50 feet according to Engineering Record, 
ol. 30, 1894, p. 189. 
rf Engineering Record, vol. 33, 1896, p. 81: -71 according to Gratacap, L. P., Geol. City of New York, 
p. 10-12. 
e Idem, vol. 37, 1898, p. 211. " Rock or hardpan." 
/Idem, vol. 33, 1896, p. 315. Verv irregular surface, varies 6 to 8 feet in distances of 15 feet. About 
e middle of the building there was a kind of pocket in the rock, a V-shaped section about 10 feel 
.'ide at top and 10 feet deep, beginning near the south side of the site and running northwest, so 
s at the rock surface sloped in three directions. Rock " rotten mica -schist." 
<j Idem, vol. 45, 1902, p. 442. Rock presumably gneiss. 
^Idem, p. 87. 
*Idem, p. 298. Cellar excavated to this depth. 
ildem, vol. 34, 1896, p. 315. Rock presumably gneiss. 
fc Robertson, R. H., architect, 160 Fifth avenue, 
assau street. 
Fifth avenue. (Average depth.) 
■xmuriBuii, i\. ii., mi. uncut, iuu 
I Boiler & Hodge, engineers, 1 Nt 
» Wills, Chas. T., builder, 156 Fifi 
