MINERAL RESOURCES OF THE STATE OF NEW YORK T53 



The muscovite has little value for sheet cutting, being much fractured 

 and splintery. 



Biotite in sheets up to 2 feet across are also found here. 



Warren county. A pegmatite occurrence near Chestertown has 

 been under development at different times and has afforded small 

 quantities of commercial mica, including muscovite and biotite. 

 The locality is mentioned in the Mining and Quarry Report for 

 191 1 under the head of Feldspar, which is also present in marketable 

 quality. It is 3 miles south of Chestertown on the ridge to the 

 east of the Warrensburg road. Two openings were made over 15 

 years ago, and in 19 13 further work was carried on by C. A. Williams 

 who informed the writer that he secured some merchantable book 

 mica and plans to continue operations during the current season. 

 The main opening is a pit 15 feet wide extended for 75 or 80 feet 

 along the course of the pegmatite which strikes northeast. The 

 full size of the body could not be ascertained at the time the writer 

 visited the locality as only the easterly wall was exposed. The 

 pegmatite is a coarse aggregate of white microcline, quartz and 

 mica. Biotite seems to be chiefly represented near the outcrop, 

 but Mr Williams states that recent work has uncovered muscovite 

 in larger amount. The books run to a foot or so in diameter and 

 usually show fractures or rulings. Black tourmaline occurs sparingly 

 in the quartz and feldspar, but it would appear that feldspar of 

 pottery grade may be obtained with a little sorting. A smaller pit 

 lies to the north of the other, the result of the earlier operations, 

 and is thought to be on the same pegmatite body, in which case 

 the occurrence must be quite extensive. 



Jefferson county. Yellow mica, probably phlogopite, is found in 

 large plates near Henderson. Muscalonge lake, town of Theresa, 

 has afforded fine examples of crystallized phlogopite of brown color, 

 but in small individuals. 



St Lawrence county. Some fine examples of phlogopite crystals 

 in the State Museimi are recorded as having been collected from 

 Somerville. Perfect six-sided prisms unmarked by fractures or 

 rulings and of brown color have a diameter of 12 inches. The exact 

 locality is not given, but it may be the same mentioned by Beck a« 

 2 miles north of Somerville, with limestone and serpentine as the 

 gangue materials. Judging from the samples, the occurrence is of 

 unusual interest. 



Small quantities of mica have been obtained from the town of 

 Fine, 2 miles north of Oswegatchie. Good sheets of reddish phlogo- 

 pite were shown to the writer as coming from that locality. The 

 last work on the deposit was in 1909. 



