388 
DESCRIPTIVE MINERALOGY. 
Erie County. This mineral is very abundant on the slate near Eighteen-mile creek, on 
the shore of Lake Erie. There are also thousands of pyritized petrifactions near Buffalo. 
Essex County. In almost all the mines of magnetic iron ore, iron pyrites occurs either in 
small grains or larger masses. It is also some¬ 
times observed in the white limestone. In the 
vicinity of Port Henry, crystals are occasion¬ 
ally found of the primary form (Fig. 448), and 
of the octahedron with the solid angles replaced 
by rectangular planes, Fig. 449 ; and also the 
dodecahedron with pentagonal faces, dodeca- 
edre of Haiiy, Fig. 450. P on d 152° 15' 52" ; 
e on e 126° 52 / 12"; e on e' or e" 113° 34 / 
41" (Haiiy). 
Franklin County. About half a mile from the residence of James Duane, Escp, near the 
road leading to Malone, there is an extensive bed of iron pyrites. On exposure to the air, 
the entire rock is decomposed, and crumbles to the ground in the form of a green sulphate of 
iron or copperas. There is a small stream in the vicinity, and it is thought that copperas 
Jefferson County. In the town of Cham¬ 
pion, this mineral occurs radiated, plumose, 
and in crystals of a white and pale yellow 
colour. The crystals are in the form of the 
octahedron. Fig. 451. d on d, over the base, 
109° 28' 16". 
Crystals similar to Fig. 452, are occasion¬ 
ally found with the preceding, on the banks 
of Vrooman lake, near the village of Oxbow. 
They are of a dark colour externally. P on 
d 152° 15' 52". 
Lewis County. About a mile and a half northeast of Natural bridge, iron pyrites occurs 
abundantly in well defined cubes, in a kind of trappean rock. It occurs also massive, and is 
of a bright bronze yellow colour. 
Near Martinsburgh, it is associated with calcareous spar, in the veins of galena which 
there traverse the limestone. The crystallized variety sometimes assumes the form of the 
cuneiform octahedron. The regular octahedron (Fig. 451) has also been observed at this 
locality. 
may be advantageously manufactured.* 
Fig. 451. Fig. 452. 
Fig. 449. Fig. 450. 
* See a communication of B. S. Roberts, in the Report of the Commissioners to survey the Ogdensburgh and Champlain rail¬ 
road. Documents of the New-York Legislature, 1841. 
