U.S. GEOLOGICAL SURVEY 
rs ^ 
MAP OF NORTHERN AND EASTERN 
PORTIONS OF MANHATTAN ISLAND, 
SHOWING CONFIGURATION OF THE ROCK FLOOR. 
Scale 
] mile 
1905 
o Borings to rock ; figures £ive elevation of rock surface, referred to 
mean tide at Sandy Hook', 
o Borings which do not reach roekfigures give elevation of bottom 
referred to mean tide at Sandy Hook. 
The blue lines are contours of the rock floor referred to the 
datum plane adopted . 
JULIUS BIEN &CO.LITW.N.Y. 
