28 NEW YORK STATE MUSEUM 



Ann about 25 or 30 years ago. More recently it has been a source 

 of feldspar for shipment and has been worked intermittently ac- 

 cording to the market demand, the last time by Dominick Ashley 

 of Glens Falls. 



The outcrop lies about 2^ miles northwest from Fort Ann at 

 the base of the gneiss ridge of which the higher part is known as 

 Putnam mountain. It is on or near the farm of Ira D. Gilmore. 

 It consists of a rather irregular area, though the general shape is 

 lenticular, with its longer direction nearly transverse to the gen- 

 eral axis of the ridge, or to the northwest. An open cut about 

 125 feet long and from 30 to 40 feet deep has been made. The 

 lens is broadest near the southeastern end where it measures fully 

 75 feet wide. To the northwest it gradually diminishes and 

 wedges out in the gneiss 50 feet beyond the end of the pit. When 

 visited by the writer the workings were partly filled with water 

 and the deeper parts of the excavation consequently could not be 

 inspected. The wall rock as seen in exposures nearby is a well- 

 laminated biotite gneiss. 



The pegmatite is made up largely of graphic granite, that is an 

 intimate mixture of feldspar and quartz, but the two minerals 

 also occur separately to a considerable extent. Masses of milky 

 quartz up to 2 or 3 feet in diameter are found and also feldspar 

 crystals of similar dimensions. The feldspar is mainly of grayish 

 color and so far as tested appears to consist largely of microcline. 

 There is present also a little pinkish feldspar which may be ortho- 

 clase. Tourmalin and the iron-bearing silicates generally have a 

 very limited representation, though the pegmatite shows much iron 

 stain, the result perhaps of pyrite. 



Alteration of the feldspar is much in evidence in parts of the 

 exposure. This results in the formation of kaolin and sericite and 

 sometimes is accompanied by a greenish coloration of the second- 

 ary products which is probably the effect of intermingled serpen- 

 tine. The presence of this mineral can not be traced to any mag- 

 nesium component of the pegmatite, but seems referable to an 

 interchange of the alkaline constituents of the feldspar for mag- 

 nesium which has been introduced perhaps by ground waters. 



Kushaqua, Franklin county. A large pegmatite body is found 

 about 4 miles north of this place on the slopes of Sable mountain. 

 It has been prospected during the last few years but has not sup- 

 plied any feldspar in commercial quantity. The outcrop lies high 

 up on the mountain near the summit at an elevation probably of 



