30 



NEW YORK STATE MUSEUM 



Concentrates. The following measurements have been made 

 upon concentrates from ores of Lead hill : 





" Arthur 



vein " 



Pit 

 unknown 



Average diameter 



.38 mm 



X 



.50 mm 

 .80 mm 

 .32 mm 



.38 mm 



X 



• 57 mm 



1 . 10 mm 



.22 mm 



Maximum diameter 



Minimum diameter 







Analyses of contact rock on Lead hill 



MICROSCOPIC ANALYSIS 



(Specimen 665 — Young Lion pit) 



Graphite. . . 



Augite 



Scapolite. . . 

 Titanite.. . . 

 Tourmaline . 



Pyrite 



Quartz 



Zoisite 



Total.. 



6.0 



54-0 



35-3 



1.5 



1.4 



•7 



•5 



.6 



100. o 



n 



H U 



*H CD 



Ave. 

 Max 

 Min. 



1 . 84 mm 



2 . 80 mm 

 1 . 50 mm 



Ave. 

 Max 



Min. 



,095 mm 

 , 190 mm 

 , 030 mm 



CHEMICAL ANALYSIS 



(Specimen collected by Bastin) 



Si0 2 47.91 



AI2O3 6.32 



Fe 2 3 33 



FeO : 3. 11 



MgO 11.86 



CaO 22.88 



Na 2 .40 



K 2 46 



H 2 0— 96 



H 2 0+ 10 



Ti0 2 .44 



CO. 95 



P 2 5 25 



S 05 



FeS 2 



C 400 



Total 100.10 



Less . .02 



Total 100.08 



The chemical" analysis by George Steiger in the laboratories of the United 

 States Geological Survey, U. S. G. S. Bui. 591, p. 40. 



The quantitative microscopic analysis by the writer by the camera-lucida- 

 polar planimeter method. These are approximate values _ by weight. See 

 page 50 for a description of the methods employed in obtaining these results 



Its variable nature and its pockety distribution are factors leading 

 to irregular supply, and precarious mining conditions. The supply 

 is by no means exhausted but the writer feels confident that Lead 

 hill can never regain the reputation that it held for so long in the 

 early days of the graphite industry. 



