THE ADIRONDACK GRAPHITE DEPOSITS 127 



with igneous material, and on the other hand an Igneous rock which 

 has melted into itself or assimilated sedimentary material. Between 

 these two types every gradation exists, thus introducing additional 



complication and uncertainty." 1 This condition is strikingly the 

 case north of the Bear Pond Mountain region (see northeast corner 

 of the map of that region) in the area between Eagle lake ( Chi 1 son 

 lake on the map) and Bear pond. It seems a mistake to map such 

 an area as though of simple composition and origin. 



The soaking effects of the Laurentian granite have been pointed 

 out before. Two syntectic rocks have been recognized: the 

 smothered Hague gneiss termed the Trumbull gneiss, and the Swede 

 Pond quartzite when similarly affected. The peculiar habit of the 

 granite in soaking the salic rocks in preference to the subsalic beds 

 has repeatedly been observed. 



Grenville Structure 



From the first reconnaissance of the Adirondacks the Grenville 

 strata have been regarded as intensely folded, metamorphosed and 

 foliated. Recently W. J. Miller has raised some doubt as to the 

 validity of such a conclusion. 2 As the blanket types of ore are mem- 

 bers of the Grenville series, it is of great practical importance to 

 know the actual conditions. Overwhelming evidence of strata 

 repeated in reversed order, of synclines and anticlines tightly 

 squeezed, supports the contention that the Grenville has been com- 

 plexly isoclinally folded, Bear Pond Mountain, the Hooper, Sacan- 

 daga, and the Flake properties being specific cases. 



Faults come in and play a major role, as in the Dixon-Faxon 

 and Graphite Products Corporation districts. The faults are not all 

 of the same age but apparently range from the middle Precambrian 

 to Postordovician in age. Reasons for this conclusion can not be 

 given here. 



THE CONCENTRATION OF FLAKE GRAPHITE 

 Probably the greatest problem confronting the graphite operators 

 of the Adirondacks is the separation of the flake graphite from its 

 associated gangue minerals. The process of separation is usually 

 subdivided into (i) the "concentration," and (2) the "refining" 

 operations. The former is performed in the mills most commonly 



1 Smyth, C. H., Jr., N. Y. State Mus. Bui. 158, p. 143. 



- Miller, W. J., " Origin of Foliation in the Pre-Cambrian Rocks of Northern 



New York," Jour. Geol. XXIV, no. 6, p. 587-619. 



