Perry and West nth Streets—Sand, 40 feet; red clay, 23 feet; to rock, 63 feet.
Ninety-ninth Street and 2d Avenue—Made ground, 8 feet; dock mud, 18 feet; sand, 21 feet; total, 38 feet.
Avenue D and 10th Street—Made earth, 6 feet; marsh mud, IO feet; quick-sand, 12 feet; shore sand and gravel, 53 feet; hard
pan, 6 feet; coarse gravel, 3 feet; total, go feet to rock.
I
am indebted to Messrs. Kimball and Thompson for the subjoined valuable
information as to recent borings in the soils above the rock-beds in
lower New York.
The
borings for the foundation of the Manhattan Life Insurance Building,
66 Broadway, showed: Sand, 34 feet; conglomerate (coarse gravel) (?),
6 feet; boulders, 2 feet 8 inches; to rock, 42 feet n 1-2 inches;
excavation in gneiss, 24 feet.
Standard Oil Building, hard pan, 44 feet below Broadway curb.
American Surety Building, hard pan, 71 feet below Broadway curb.
Empire Building, hard pan, 54 feet below Broadway curb.
Washington Life Building, hard pan, 75 feet below Broadway curb.
Mr.
Chas. H. Deans remarks on the above that " in all the work the material
over the hard pan was practically the same, being a very fine sand,
with a great deal of fine mica and some loam in it. In some spots it
was an actual quick-sand."
The "hard-pan" is a compact clay, packed with small stones.
I owe to Engineer Chas. J. Bates the following details of borings in the lower part of Broadway, and adjoining streets:
Broadway and Vesey Street—Top earth and medium sand, 12
feet; fine sand, 54 feet; running sand, 15 feet.
Broadway and Fulton Street—Top earth, 10 feet; medium
sand, 6 feet; fine sand, 28 feet; quick-sand, 4 feet; running sand,
35 feet-Broadway and Dey Street—Top earth, 10 feet; medium sand,
7 feet; fine sand, 17 feet; running sand, 38 feet; quick-sand, 5
feet.
