3& NEW YORK STATE MUSEUM 



Occurrences in Newcomb and Minerva 



The economic collections of Columbia University contain speci- 

 mens of contact graphite from these townships. Further informa- 

 tion is not available. 



The Pottersville Prospect 



This property is in the township of Chester, Warren county, 2.y 2 

 miles south of Pottersville, south of Loon Lake mountain, within 

 the North Creek quadrangle. 



This limestone-contact deposit has been noted by W. J. Miller, 1 

 who has mapped the area in which it lies, as Grenville gneiss. It 

 is situated under the lee of a great fault line escarpment — the 

 southern face of Loon Lake mountain. 



In the field it was found that several beds of limestone, inter- 

 bedded with amphibolite and with other members of the Grenville 

 series, are cut by a dike of pegmatite which spreads over the present 

 surface, but probably originally was a laccolith. The dip is 25 ° to 

 30 S 78 W (magnetic). No commercial importance can be 

 attached to this locality. 



The Mammoth Cave Prospect 



This property is in the township of Warrensburg, Warren county, 

 one-half of a mile north of Warrensburg, on the east side of the 

 International highway. 



This prospect consists of an opening that has been dubbed 

 " Mammoth cave." The cave is a natural one due to the solution 

 of the Grenville limestone, and has been somewhat enlarged by 

 prospectors. It is 25 to 30 feet long, following the dip of the rocks 

 (22 N 8o° E). Overlying the limestone is a mass of typical 

 syenite. Where this rock has come into contact with the limestone 

 a thin layer carrying graphite flakes, which are often one-eighth of 

 an inch in diameter, has resulted. The footwall is a contact rock 

 composed of white pyroxene and scapolite and shows specks of a 

 brilliant emerald-green mineral whose identification is not certain. 



While this prospect exhibits some rather interesting features we 

 can dismiss it from our minds as a commercial source of graphite. 



SUMMARY OF THE NORTHERN AREA 

 A line can be drawn across the graphite area of the eastern 

 Adirondacks north of which will be found almost all the limestone 



1 Miller, W. J., N. Y. State Mus. Bui. 170, p. 82. 



