THE ADIRONDACK GRAPHITE DEPOSITS 



69 



water is flowing, giving off a strong order of copperas (iron sul- 

 phate), and the dismal ruin of a huge mill with several acres of 

 tailings. 



The geological relations exhibited here are puzzling and among 

 the most difficult the writer has ever seen. The rock mined was a 

 very dense, hard, fine-grained feldspathic schist (arkosite) dipping 

 at an angle of yS° with small size flake, perhaps running from 

 2 to 3 per cent, and considerable amounts of pyrite and perhaps 

 pyrrhotite. If the conditions shown on the map are correct, then 



WWv 



mm. 



PYRITE 



GALENA 



Fig. 15 Camera-lucida drawing of polished specimen 

 of vein pyrite from Rock Pond pit, showing the 

 microscopic intergrowths of pyrite and galena, the 

 latter replacing the former. X 20. Specimen 650 P. 

 H. L. Ailing, 1918. 



'^'^■'->. 



the miners were operating in a block of ore faulted on all sides. 



Where this rock should be placed in the geological column is a 

 problem that can not be attempted at this time. 



The graphite must be regarded as of organic origin but its 

 relation to the pyrite, for such exists, is rather obscure. Examina- 

 tion shows that the pyrite is of two generations. The first intro- 

 duction of the pyrite preceded the faulting, while the perfect cubes 



