No. 275, 
187 
to the statement of Mr. D. senior, who made the borings, and who also 
states that the water rose within 30 feet of the surface. 
The shaft of the city reservoir in I3th-street, a few feet east of 
Eroadway, is 113 feet deep and 17 in diameter, with 2 adits at bottom, 
one 75, the other 100 feet long. The rock was reached at about 20 
feet. 
In the same street, a few rods west of Broadway, the rock was 
reached at the depth of about 3 feet, approaching in one place very 
near the level of grading. At IGth-street,^ corner of 2nd, 3rd, and 4th 
avenues, the rock appears, and the soil as we go northward continues 
to grow thinner and thinner. 
As we approach the East river from any point in the middle of the 
island, between 1st and 20th-streets, the rock dips down to a depth 
of 90 or 100 feet below grading, as evinced in the shaft sunk in this 
part of the city. In conclusion, the diluvium and stratified sand and 
gravel, it appears, extends on the west side of the island as far as 31st- 
street, and on the east side to 16th-street; and notwithstanding this 
formation is found in every other section of the island, it is in com- 
paratively small quantities and needs not a particular description. The 
mineral character of these materials will be noticed in the description of 
the boulders. 
IV. 
Allvial Beds and Valleys on ike Island, 
There are three principal beds or valleys of alluvium that demand 
particular description. The first lying in the very centre of the city, 
includes nearly the whole length of Centre-street with Elm, on the 
west, and Orange and Mulberry-streets on the east, to the neighbor- 
hood of Canal-street. This valley was formerly called the Collect, as 
it was a receptacle for the draining of the adjoining higher grounds. 
In some portions it was a mere quagmire, and in others a collection of 
stagnant water 50 or 60 feet deep, and is said by some of the oldest 
citizens to have had an outlet communicating with the East river along 
what is now called Roosevelt-street; and another, with the Hudson 
across the Lispenard meadows, crossing Broadway at what was then 
called the stone bridge, (now corner of Broadway and Canal-street.) 
The Lispenard meadows extended from Broadway to the Hudson, and 
from the vicinity of St. John's church to Spring-street on the north, 
including the range of Thompson, Laurens and Wooster-streets. 
