MAGNETIC OXIDE OF IRON. 9 



O'Niel Mine. This is about a quarter of a mile northeast of the preceding, and is a vast bed 

 of the magnetic oxide of iron. The ore is generally hard and compact, but is often traversed 

 by seams which are studded with crystals having the form of the regular octahedron, which 

 is occasionally modified, and rarely passes into the form of the cube. (See Fig. 1, 2, 3 and 5.) 



This mine has been extensively worked. The ore contains iron pyrites, and requires to be 

 roasted before it is used by the smelter ; but it yields a good iron of the red short variety. 

 Its immediate associates are white calcareous spar, which is abundant, rose coloured garnet, 

 green coccolite, dark coloured pyroxene and massive hornblende ; amianthus in delicate fibres, 

 serpentine, and probably arragonite also occur. 



The O'Niel ore is strongly attracted by the magnet, and possesses polarity. The following 

 is its composition : 



Protoxide and peroxide of iron, 95. 75 



Silica and alumina, 4. 25 



The Clove or Wilks Mine, which is the most westerly of the gi-eat iron ore deposits now 

 wrought, is situated about a mile south of the village of Monroe. The ore is strongly attracted 

 by the magnet, and is sometimes granular and pure, at others it is largely mixed with iron 

 pyrites. It makes 7-ed or hot short iron, and generally requires roasting before it is used. At 

 the south end of the mine, which has been opened about 500 feet, the ore occurs in the form 

 of a black powder, which is here called jf^we or soft ore, and is probably the result of the 

 decomposition of iron pyrites. Large quantities of this variety have been obtained, and it 

 does not require the ordinary roasting process. 



According to Dr. Horton, the solid ores of this mine are in layers having the direction and 

 dip of the rock in which they occur. The layers are from a few inches to a yard or more in 

 thickness. The immediate associates of the ore are mica, hornblende, quartz, feldspar, asbes- 

 tus, occasionally carbonate of lime, a kind of serpentine or soapstone, and perhaps, though 

 rarely, chrome-iron ore in minute octahedrons. 



The following are the constituents of one of the purest specimens of the Clove ore, by my 

 analysis : 



Protoxide and peroxide of iron, 98 . 90 



Silica and alumina, 1.10 



But the granular magnetic ore is usually mi.xed with iron pyrites, as above stated. 



It may be added, that masses of well characterized hematite are found on the surface, in 

 the immediate vicinity of this mine. 



The remaining deposits of the magnetic oxide in this county are much less important tlian 

 those previously described. They are principally in the tovwi of Cornwall. 



A bed of the magnetic oxide of iron occurs about one or two hundred yards east of the 

 reservoir at West-Point. Its quantity is not known, but it has been traced, at short intervals' 

 for some distance in a southerly direction towards Meek's Mine, on the western part of Bear 

 hill, southwest of Buttermilk falls. The ore of the latter mine is said to be titaniferous.* 



• Mather. New-York Geological Reports, 1839. 



Part I. 2 



