1 68 NEW YORK STATE MUSEUM 



pegmatite does not conform to the structure of the gneiss, but 

 breaks across the foliation, which it would naturally do if it were 

 in the nature of a stock rather than a dike. 



The occurrence still possesses value for the production of pottery 

 spar. The main drawback at present is the expense of haulage. 



CORINTH, SARATOGA COUNTY 



Quarry of American Feldspar & Milling Co. 



This quarry is a practically undeveloped property from which 

 only trial shipments have thus far been made. The Corinth Feld- 

 spar Co. did some work on it in 1908, but relinquished control to 

 the company named, who are its present owners. The property is 

 about 3 miles southwest from the Corinth railroad station and 700 

 feet above it. 



The pegmatite has a width of about 60 feet and is exposed over 

 a vertical distance of 130 feet. It has not been sufficiently developed 

 to indicate the shape of the body, but it is perhaps an elongated 

 lens or dike intruded parallel to the foliation of the surrounding 

 gneiss which trends a little west of north. There is more or less 

 of the rock in evidence over a distance of 2000 feet. The peg- 

 matite consists mainly of an intergrowth of quartz and feldspar, 

 with only a small part of either mineral in free crystals serviceable 

 for pottery uses. The feldspar is an untwinned variety that appears 

 to be orthoclase, a rather rare form for Adirondack pegmatites. 

 There is considerable biotite which is so equally distributed as 

 to render its separation a matter of difficulty. 



MAYFIELD, FULTON COUNTY 



Tyrell quarry 



This occurrence of pegmatite was worked a few years since by 

 the Claspka Mining Co. along with the quarry near Batchellerville. 

 It is situated in the town of Mayfield, 3 miles west of Cranberry 

 creek, on the farm of Richard Tyrell. The outcrop lies well up 

 on the gneiss ridge, 800 or 900 feet above the railroad which 

 terminates at Northville, 5 miles above Cranberry creek. 



The main body of pegmatite is opened by a pit 50 or 60 feet 

 across and heading into a ridge in a northeasterly direction. The 

 quarry face as left by the former operations is over 50 feet high. 

 The materials are coarsely crystallized, the quartz and feldspar 

 reaching a maximum diameter of 3 or 4 feet. The feldspar in- 

 cludes pinkish microcline and a white striated albite. The latter is 



