478 
GEOLOGY OF THE FIRST DISTRICT. 
immediate shore of the Hudson river, about one or one and a half miles below Caldwell’s 
landing, and above Tompkins’s quarries. Prof. Cassels describes it as four or five rods wide, 
measured across the strata, which are rather thick layers and blocks than strata. It is stated 
that blocks of any reasonable size can be quarried here, free from cracks and flaws. It is of 
various shades of color, from a deep spotted green to a beautiful bluish white. It is gene¬ 
rally free from pyrites, but some block’s contain crystals of this mineral. The occurrence of 
this mineral wouldinjure it for sawing and polishing, but Mr. C. reports that most of the quarry 
is free from it, and that the verd-antique marble from this place takes a high polish. The 
quarry is on the shore, and vessels can come directly along side. The quarry belongs to 
Sampson Marks, esquire. 
I will add some of my own observations on some of the localities mentioned by Dr. Hor¬ 
ton,. and some others belonging to the same rocks in Orange and Rockland counties. 
The bed of limestone described by Dr. Horton, near Fort Montgomery, is traversed by one 
of the transverse lines of fracture and upheave that have produced great derangements of the 
strata. The direction of the line of bearing of the strata afiected by this line of disturbance 
is N. 20° W, from the house of Mrs. Pell, below Fort Montgomery. The strata are much 
confused over a breadth of half a mile to a mile, from northeast to southwest. The limestone 
on the hill southeast of Peekskill, that has been mentioned as ranging in a southeast and 
northwest direction, is also situated on this line of disturbance, as also the southerly part of 
Anthony’s Nose mountain. 
The bed of limestone near Fort Montgomery can be traced at intervals about three miles to 
the north-northeast. There are numerous excavations that have been made in it, in search of 
the precious metals, but no metallifereous minerals were seen at any of these localities but 
pyrites, magnetic pyrites, and grains of magnetic oxide of iron. Augite, sahlite, mica and 
hornblende, are the common associates of the limestone, and a slaty pyritous gneiss is the 
rock that is most commonly adjacent. At a locality near^Mr. Potter’s, one mile northwest of 
Fort Montgomery, the pyritous limestone has been blasted out to make copperas! The pyrites 
here are mixed with white augite, limestone and serpentine. The strata are in great con¬ 
fusion. 
A great variety of minerals may be obtained in this vicinity, though not as beautiful as in 
many other places. Am ong them may be mentioned pyrites, (both common and magnetic), 
magnetic oxide of iron, sphene, augite (white, grey and green), coccolite,, hornblende, man- 
ganesian garnet, limestone (white), verd-antique, serpentine and schorl. Allanite, crystal¬ 
lized with brilliant faces, I found there in 1827. 
Another limestone bed was observed on the roadside above Queensbury Forge, about four 
miles from Fort Montgomery. It contains brucite, spinelle, sahlite, coccolite, and glassy 
green hornblende. About one-half or three-quarters of a mile farther on, another bed of the 
white limestone, containing brucite, augite, coccolite and scapolite, was observed. Gneiss 
rocks are associated. 
At the Forest of Dean iron mine, six miles west-northwest of Fort Montgomery, an exten¬ 
sive bed of this limestone exists. The extent has been described by Dr. Horton. Some of it 
