THE MINING AND QUARRY INDUSTRY 



51 



The tailing's arc again treated on a machine supplied with stronger 

 magnets, which takes out the remaining magnetite as concentrate 

 and the hornblende as middlings product. The tailings from this 

 separation consist of apatite and quartz carrying about 60 per cent 

 of tricalcium phosphate in a marketable form. They are shipped 

 to fertilizer manufacturers. The hornblende middlings also con- 

 tain 30 or 35 per cent apatite, but they are not utilized to any 

 extent at present. The first separation is made on Ball & Norton 

 endless belt machines and the second on Wetherill machines. 



So far as known, the only locality in New York State where 

 apatite occurs in deposits free from admixture with other minerals, 

 is near Crown Point, Essex county. The deposit has been described 

 by Emmons 1 who named the mineral eupyrchroite on account of 

 the green phosphorescence which it displayed when heated. An 

 analysis gave about 85 per cent tricalcium phosphate. The deposit 

 consists of botryoid concretionary masses of grayish color and 

 occurs in gneiss near the contact with limestone. It was mined on 

 a small scale about 50 years ago. 



The crystalline limestones of the Adirondack's and southeastern 

 New York frequently contain apatite, but the occurrences ar eonlv 

 of mineralogic interest. Among the best known localities are 

 Gouverneur and Hammond. St Lawrence co.. Natural Bridge 

 Lewis co., and Amity, Orange co., from which many specimens have 

 been taken for museums. 



CARLO. \ DIOXII) 



Carbon dioxid, or carbonic acid gas as it is commonly called, is 

 produced commercially at Saratoga Springs. It accompanies the 

 mineral waters, issuing in quantity from the wells and natural 

 springs. 



The gas is found at depths ranging from 150 to 600 feet. -Though 

 its source and the precise conditions under which it accumulates are 

 more or less conjectural, there seems to be little doubt that the pro- 

 ductive area lies along a zone of fracture and faulting which involves 

 the sedimentary and underlying crystalline rocks of the region. 

 One marked fault has been traced from Saratoga southwest toward 

 Ballston, approximately in line with the wells.- The geologic sec 

 tion includes Potsdam sandstone, resting unconformably upon Pre- 

 cambric gneisses, and Lower Siluric strata as high up as the Utica 

 shale. The general experience in drilling has been that the gas 



'Geol. N. Y. 2d Dist. 1838. p. 252. 



'Darton. N. H. N. Y. State Mus. Rcp't 48. i8 Q4 . 2:50. 



