94 NEW YORK STATE MUSEUM 



entirely of augite and scapolite with brilliant green spinel and brown 

 tourmaline. It is a contact rock. It seems to cut irregularly across 

 the bedding of the sedimentary rocks. It seems likely that the 

 Algoman granite was in part, at least, responsible for its develop- 

 ment. 



The series of rocks that underlies the ore is unusually complete. 

 Directly beneath is the Hague gneiss, which forms the walls of the 

 wedge-shaped pit. It is not quite like the typical rock as exposed 

 at Hague, for instead of sillimanite, the rock contains biotite. 

 Below is the para-amphibolite (the Dresden), followed by the lime- 

 stone that occurs at the Rowland property. This is the Johnsburg 

 limestone of the writer. .It has suffered shearing and stretching in 

 a manner similar to that experienced by the Faxon. It is found 

 only here and there. Up to this point in the description of the 

 graphite properties, beds lower down in the geologic column have 

 not been encountered, but the Sacandaga mine furnishes a new bed. 

 This is another quartzite that will be termed the Sacandaga quartzite. 

 The thickness of this formation is unknown. 



The structure of the beds has already been outlined; a syncline 

 whose axis lies in a northwest-southeast direction, pitching to the 

 northwest, has been truncated by erosion so that the present surface 

 of the hill slope cuts diagonally across the beds, which outcrop in 

 the form of a V with the apex to the southeast. In vertical sec- 

 tion this gives a V inclined 30 into the hill slope. The accom- 

 panying block diagram is an attempt to present this a little more 

 concretely. The southern pit is located at the very apex of the fold. 

 When the pit was abandoned, the miners had worked out all the 

 ore, inasmuch as they encountered the Hague gneiss on three sides. 



The other two pits are located upon the northeast limb of the fold. 

 The miners confined their operations to the single outcrop. They 

 have not followed down the dip of this limb far enough to reach the 

 bottom of the fold, but it is evident that at the pits the amount of ore 

 is exceedingly limited. It is possible that more ore could be found 

 farther along the strike to the northwest. 



Sedimentary type of ore. The ore that has received serious 

 attention is very probably the Dixon schist, but the Sacandaga 

 exposure shows a decided variation from the usual type. It is a 

 feldspar schist, very low in quartz but high in graphite, the latter 

 running about 10 per cent in the central zone of the bed. The 

 feldspar is chiefly microcline-microperthite, comparatively fresh, 

 while the subordinate introduced (3) oligoclase-andesine is almost 

 completely altered to sericite. There are two micaceous minerals 



