No. 275.J 
IS5 
Ticinity, and from the materials themselves being traceable to the origi* 
nal rocks, whence they have been transported. The southern part of 
the island contains the largest amount of these materials. In the south- 
eastern extremity of it, usually denominated Corlear's hook, the sur- 
face has been graded in some places 70 or even 80 feet below the natu- 
ral level, and shafts have been sunk 75 or 80 feet more without reach- 
ing the rock. The diluvium and alluvium together are therefore in this 
vicinity at least 150 feet, the streets having been graded in some places 
half that depth below the original soil. It is proper to state that the 
whole of Corlear's hook and its vicinity originally consisted of a series 
of conical hills of diluvial sand, gravel and pebbles, with masses of all 
sizes, from pebbles to boulders 15 or 20 feet in diameter; all of which 
have been removed ani deposited in the neighboring valleys and low 
grounds. Here were collected, not only the largest quantity, but the 
greatest variety of rocks that were found in any part of the island. 
We will now enumerate the different depths at which the rock has 
been reached by borings for water, or for other purposes, in different 
parts of the island w^hich are covered by alluvium or diluvium. Most 
of these borings were commenced in this city many years ago by Mr. 
Levi Disbrow; and the same business is successfully conducted by his 
son, Mr. John Disbrow, from whom most of the subjoined facts were 
obtained. 
Commencing at Corlear's hook, we find a shaft was sunk at Mr. 
James P. Allaire's works, in Cherry-street, about 80 feet through dilu- 
vium, stratified sands, clays, or gravel, without reaching the rock. 
Again to the westward about half a mile, at the foot of Jefferson-street, 
the rock was reached through 10 feet of diluvium, and 40 feet of stra- 
tified sands, and gravel alternating with clays. 
At Fulton market a shaft was sunk through 15 feet of artificial 
ground, then 115 feet of stratified sands, blue clay and river mud 
alternating, and the rock was struck at the depth of 130 feet. 
At Holt's Hotel, a few rods north of the last mentioned place, a 
shaft was sunk through 126 feet of strata like those at the market, and 
the rock reached through a bed of gravel, and the shaft sunk 500 feet 
into the rock, which is gneiss with veins of quartz and granite; 200 
feet of the upper part of the bore is a three inch hole, and the remain- 
der two and a half inch. The water obtained from this well was at 
first tolerably good, and promised to be very serviceable, but since hat 
[Assem. No. 275.] 24 
