THE ADIRONDACK GRAPHITE DEPOSITS 8l 



it rarely presents a pure type of rock. The writer's interpretation 

 is that it is in part sedimentary and in part igneous ; the Laurentian 

 granite has injected it, soaked it, and has assimilated sufficient 

 quantities to form a syntectic rock. It is suggested that this 

 represents the Swede Pond horizon. The presence of the Lau- 

 rentian, the Algoman granite, or the siliceous and argillaceous 

 character of the Faxon limestone may be factors in the production 

 of the contact type of amphibolite which forms the base and top 

 of the Faxon formation. In the field north of the mine the syntectic 

 Swede Pond gneiss is cut by a diabase dike, 2^2 feet wide running 

 N 6o° E. 



If the above relations hold, the following is especially important, 

 not only scientifically but as bearing on the problem of the graphite 

 resources of the State. Resting upon this syntectic rock, and forming 

 the slopes of Catamount mountain is a sillimanite schist, which 

 furnishes the type example of the Catamount schist (see the Bear 

 Pond mountain region). It is believed that the full thickness of 

 the Catamount is shown here. Certain phases are somewhat 

 graphitic and the inference is strong that we are not far from the 

 horizon of the Bear Pond schist, the ore-bed of the Bly property. 

 That such is the case, however, is by no means demonstrated, but 

 the suggestion is worth considering. If such is the case, then, there 

 are two distinct graphitic beds. From what has been learned it is 

 safe to say that the lower (stratigraphically), or Dixon schist, is the 

 better of the two. Provided that the stratigraphy as here developed 

 is actually the true state of affairs, then prospecting for more 

 graphite takes on a new significance. 



The ore. A specimen taken from the ore bin, representing the 

 typical rock mined, was found under the microscope to be a quartz- 

 feldspar schist, abnormally high in graphite and pyrite, the latter 

 running 25 per cent by weight of the rock. Biotite and phlogopite, 

 which are present in greater amounts than is usually the case, are 

 interleaved with the graphite like leaves in a book. In addition to 

 these differences from the normal Dixon schist the presence of 

 diopside (a member of the pyroxene family) and tourmaline must 

 be noted. Material from the rock dump reveals many evidences 

 that igneous action of the pegmatitic variety has taken place in this 

 vicinity. Contact rocks of all sorts are plentiful, although actual 

 access to them in situ is impossible. The peculiar nature of the ore 

 strongly suggests that redistribution and concentration of the 

 graphite flake has taken place, resulting in a rich zone within the 



