62 NEW YORK STATE MUSEUM 



Anthony carry considerable magnetite. Also pegmatite dikes cut- 

 ting the metagabbro at the feldspar mine i}i miles southwest of 

 Linwood school carry as much as lo to 15 per cent of magnetite 

 in masses up to 6 inches across. As recently pointed out^^ at some 

 length by the writer, magnetic iron ores are very commonly asso- 

 ciated with such rocks throughout the Adirondacks, and the theory 

 has been advanced that the ore was mostly or wholly derived from 

 the old iron-rich metagabbro by the hot pegmatitic fluids. 



Graphite 



An abandoned graphite (so-ca-lled "black lead") mine is located 

 i^ miles due west of Conklingville (see map). A few years ago 

 H. L. Ailing described-* this mine somewhat in detail, and the in- 

 terested reader should turn to that account. According to Ailing, 

 " the property was opened in 1906 by the Glens Falls Graphite 

 Company. In 191 1 the Sacandaga Graphite Company took over 

 the mine and mill." The abandoned mill stands by the road one- 

 third of a mile south of the mine. The open cuts of the mine lie 

 in a lens of Grenville strata inclosed by granite. One layer of the 

 Grenville, 5 to 10 feet thick, is a graphite-rich schist. Ailing pre- 

 sents a block diagram of the locality showing the structure of the 

 Grenville as that of a pinched syncline. To the present writer this 

 diagram seems to be altogether too theoretical. For example, gar- 

 net (" Hague ") gneiss lies on the north side of the graphitic schist, 

 but just on its south side the rock is granite containing some scatter- 

 ing garnets. A very few little lenses (i to 2 feet long) of lime- 

 stone lie near the graphitic schist, but nothing like so much lime- 

 stone in two distinct horizons was observed as indicated in the 

 block diagram. In fact the only Grenville rocks shown are garnet 

 gneiss, very little limestone, some quartzite, and the graphitic schist, 

 the total width of these being only 30 to 40 feet. In the south pit 

 the strata strike east-west and dip north 30 to 40 degrees. In the 

 north pit the strike is north 60 degrees west, and the dip north 50 

 degrees. Since the only exposures of Grenville occur in and near 

 the mine pits, the drawing of such a large (one-fourth of a mile 

 long) clearly defined block diagram hardly seems warranted by the 

 field facts. Finally, the writer found no good reason for indicating 

 the presence of a younger so-called "Algoman " granite in the 

 diagram or assuming its presence in the accompanying discussion. 



Econ. Geol., 14, 1919, p. 509-35, and 16, 1921, p. 227-33. 

 N. Y. State Mus. Bui. 199, 1918, p. 92-96. 



