MINERAL RESOURCES OF THE STATE OF NEW YORK 85 



is recorded by the Mineral Industry for that year. The next devel- 

 opment of importance took place at the Hooper Brothers mine where 

 the first use was made of mechanical separation for producing 

 garnet concentrates. The mine and mill were located just west of 

 North River in the town of Minerva, Essex county. The enterprise 

 was abandoned after a time and mining started at the locality on 

 Thirteenth lake, which is operated by the North River Garnet Co. 

 with F. C. Hooper as president and manager. 



References 



Hooper, F. C. The American Garnet Industry. The Mineral Industry, v. 6, 



1897 

 Kemp, J. F. & Newland, D. H. N. Y. State Geol. 17th Ann. Rep't, p. 548-49, 



1897 

 Magnus, H. C. Abrasives of New York State. N. Y. State Geol. 23d Ann. 



Rep't, 1904 

 Merrill, F. J. H. Mineral Resources of New York. N. Y. State Mus. Bui. 15, 



1895 



Miller, W. J. The Garnet Deposits of Warren county, New York. N. Y. State 

 Mus. Bui. 164, p. 94-105, 1914 



GRAPHITE 



BY HAROLD L. ALLING 



Graphite has been mined more or less extensively in the State 

 since about the middle of the last century. The earliest operations 

 probably were in connection with the Lead hill deposits near 

 Ticonderoga which were mentioned in the reports of the First Survey 

 published in 1842 and which in the next decade were under operation 

 by an enterprise that eventually became the American Graphite Co. 

 which is still in existence. The mines of Lead hill (also known as 

 Chilson hill) were based on occurrences of crystalline graphite within 

 contact zones produced by a coarse granite that were of rather 

 sporadic character; later operations were transferred to the dissemi- 

 nated type of deposits in which graphite occurs evenly distributed 

 through the mass of a quartzite or quartz schist, and these have 

 since been the main source of supply. 



General features of occurrence. The geology of the graphite 

 deposits has been the subject of a careful investigation which is 

 the basis of a report recently issued by this office (see list of 

 references). The investigation has established the fact that the 

 commercial deposits are foiuid within the Grenville series of ancient 

 metamorphosed sediments. The deposits are practically restricted 

 to a stratum of quartzite or quartz schist that ranges from 3 to 30 



