USEFUL METALS 



LOO 



in Troy about two miles northeast of the village bearing that 

 name. Three veins of the ore were worked about the middle of 

 the nineteenth century and the resulting iron used only locally 

 on account of the great distance from the railroad. A portion 

 of this ore was worked in a foundry on the banks of the M iisquoi 

 river near the ore deposit, while a part was shipped to St. John- 

 bury, 50 miles distant. The freedom from sulphur and phos- 

 phorus of this ore made it especially desirable for all purposes 

 where an extremely tough steel was sought. The ore bodies 



FIG. 105. Magnetite mine, Cornwall, Pennsylvania, showing structure 

 of the ore. (Photograph by T. C. Hopkins.) 



represent primary segregations in a peridotite magma in 

 Cambrian terranes. They are not worked at present. 



In the northward extension of this belt into Canada large 

 lenses of magnetite are encountered in Megantic County, 

 Quebec. These ore bodies are more or less lens-shaped and 

 occur near the outer margins of the peridotite or even within 

 the peridotite itself. The ores represent differentiation products 

 in the peridotite magma. The mines are still prominent pro- 

 ducers. 



The third division of the Appalachian belt is widely known as 

 the Clinton ore of Silurian age. These ores are sometime-; 

 called fossil ore, pea ore and dyestone ore, but the term Clinton 



