36 NEW YORK STATE MUSEUM 



servable in extensive crushing and faulting of the country 

 rocks. 



The deposit on Mt Bigelow is of different character than the 

 others. The garnet there is found along the contact of 

 anorthosite in irregular and- lenticular bodies that consist in 

 greater part of the single mineral. It has a massive appear- 

 ance and breaks into granular particles but occasionally shows 

 a platy fracture like the crystal garnet. The principal im- 

 purity is a greenish pyroxene. The masses measure as much 

 as 40 feet in thickness. Along- with the garnet there are bands 

 of amphibolite and crystalline limestone, the whole assemblage 

 having the appearance of a sedimentary series which has 

 been caught up by the anorthosite during its intrusion and 

 metamorphosed. 



The capacity of the mines is much greater than the average 

 output. The production could be raised to 10,000 tons a year 

 without taxing the present facilities. The North River Garnet 

 Co. has the only property that is equipped for work through- 

 out the year. It is the only company also that makes use of 

 mechanical methods for recovery of the garnet. The mines and 

 mill are situated on the slope of a mountain on the east shore 

 of Thirteenth lake. The whole western face of the mountain 

 consists of the garnet rock, the supply of which is practically 

 inexhaustible. The rock is crushed and then run through 

 special types of jigs. Close work is required of these in order 

 to effect a separation of the garnet and hornblende which 

 differ by only half a unit in their specific gravity. The garnet 

 concentrates, however, are brought up to a high degree of 

 purity. 



The shipping point for the region is North Creek. The 

 garnet is shipped unsized in bags. 



The manufacture of garnet abrasives in this country is lim- 

 ited to a few companies and there is very little demand for the 

 mineral for export. The mining field, therefore, can not offer 

 encouragement to new developments so long as present facili- 

 ties remain so largely in excess of the market requirements. 



In the last two or three years a small quantity of Spanish 

 garnet has been imported into the United States for manufac- 

 ture. This garnet is said to be obtained from river sands. It 

 is cheaper than the domestic garnet, but on account of its uni- 

 formly small size is useful only in a limited way. The imports 

 for the year 1909 amounted to 536 short tons valued at $10,315. 



