No. 275.] 
131 
formation. It occupies an area of some 400 to 600 acres, and much of 
it lies near to the water. 
This stone is now quarried extensively on the banks of the Hudson 
at Tompkins' quarries. Mr. Tompkins purchased 20 acres of this land 
on the shore of the Hudson two years ago for 100 dollars per acre, 
which was thought an extravagant price. It is a ledge of limestone 
rock 75 to 100 feet high above high watermark, with deep water along 
side, so that vessels are loaded with great ease. The stratum at the new 
quarry is from 300 to 500 feet thick, (measured across the strata,) from 
the shore to its junction with the talcose slate rock. Many thousand 
tons of this stone are shipped annually to New- Jersey, where it is burnt 
into lime with dust anthracite at a small expense. The lime is in part 
used as a stimulant manure in New- Jersey, and part is barrelled and 
sent to the New- York market. Each acre of this limestone ought to 
to yield, in course of working down to w^ater level, 600,000 barrels of 
lime, upon which a mean profit of 25 cents per barrel ought to be esti- 
mated. Most of this limestone is gray, but some is black and variegat- 
ed, and might make a pretty marble. 
The " marble quarry,'' as it is called, is on the banks of the Mini- 
shecongo creek, about two and a half miles west of Grassy Point. The 
most extravagant reports were circulated in relation to this quarry soon 
after its discovery. 
The rock is composed of serpentine, chlorite, diallage, hornblende, 
limestone, and other substances, and is such a mixture of materials of 
different degrees of hardness that it could never be polished with advan- 
tage, even if it could be easily quarried. 
A limestone quarry has been opened about three-fourths of a mile 
west of Capt. De Camp's, in Haverstraw, on land belonging to John 
Brooks. Much of the stone is white, granular, crystalline limestone, 
with thin tortuous black veins of the same material, and if good blocks 
of this character could be obtained it would make a beautiful marble. 
Specimens are deposited in the State collection. This stone is said to 
make a fine lime, and one or two kilns of it have been burnt. 
Verd-antique. 
This rock occurs in small quantities in various places in Rockland 
and Orange counties. Those in Orange will be described by Dr. Hor- 
ton in the appendix to this report. One only of economical importance 
was observed in Rockland county. It was discovered by Prof. Cassels, 
