140 
AMERICAN GEOLOGY. 
centre of the rein. The width is variable, a mass frequently 
extending beyond the usual limits of the vein. The Pendfield 
mine in Essex county, N. Y., (fig. 26), swells out 160 feet. 
Fie. 26 . 
The ground plan takes in this immense expansion of the vein, 
showing in addition the rich belt of ore by a dotted line which 
extends along the middle of the vein. The average width of 
the vein is 40 feet. Its line of bearing is northeast and south¬ 
west, and has been exposed by the^ removal of its covering 
about 20 rods, but it has been traced over half a mile. 
The ore adjacent to either wall is largely intermixed with 
quartz, while the middle is a solid mass of unmixed ore. The 
rock of this section is gneiss dipping S. E.j this vein of ore co¬ 
inciding with the lamination of the rock. 
The iron manufactured from this ore has a high reputation. 
It was tested at the Navy Yard at Washington, and was found 
more suitable for cables and chains than any iron of the coun¬ 
try, which had been submitted at that time to the necessary 
tests. The superiority of this ore depends much upon the vein¬ 
stone. Quartz or flint forms an admirable flux for iron, when 
the quantity is too great it is removed by water. There is no 
pyrites or phosphate of lime intermixed with it, and the forge- 
_ 4 
man has to deal with a pure oxide of iron. This ore is uni¬ 
form in quality, is of dull black color, rarely bright, but 
crystalline and strongly magnetic. This vein has furnished 
ore for thirty years, but has been worked only in the forge and 
into blooms. The supply will be equal to any demands which 
are likely to be made for ore, inasmuch as it is prolonged 
