QUARRY MATERIALS OF NEW YORK l6l 



ous bathyliths and bosses of granite, covering a larger portion of 

 the surface than in any other part ; the granites are mainly coarse 

 varieties, rich in quartz and containing segregated masses of peg- 

 matite. The conditions thus appear very favorable for the occur- 

 rence of extensive bodies in that section, but the remote and 

 inaccessible nature of much of the area has rather discouraged 

 exploration. 



In the Highlands region and southward into Westchester county 

 pegmatites are quite abundant but only rarely reach workable pro- 

 portions. They occur mainly in the Precambric gneisses, but may 

 be of much later age than the latter as the granite invasions con- 

 tinued down into Siluric time. The principal bodies that have been 

 worked are near Bedford, Westchester county. In the central 

 Highlands there is much pegmatite and coarse granite in evidence, 

 usually pinkish or grayish in color, but there are no developed 

 quarries. The pegmatites occur in considerable bodies in the 

 vicinity of some of the magnetite deposits. 



The present description of the pegmatite localities includes men- 

 tion of all of present or prospective importance that have come to 

 the writer's attention during rather extended travels in the field. 

 A few have been mentioned in previous reports of the State Mu- 

 seum, and many of the better known occurrences are given detailed 

 treatment in Bastin's monographic bulletin, " Economic Geology of 

 the Feldspar Deposits of the United States," already cited. 



CROWN POINT, ESSEX COUNTY 



Quarry of the Crown Point Spar Company 



The pegmatite quarry worked by the Crown Point Spar Com- 

 pany is on Breed's hill, south of Crown Point, about i 1 /^ miles west 

 from Lake Champlain. The pegmatite outcrops on one of the 

 summit knobs, 500 feet or more above the lake level. It was dis- 

 covered some years ago by Charles Wait of Crown Point, the 

 present manager in charge of the quarry. It is apparently a large, 

 somewhat irregular lens or stock, with a longer diameter running 

 northeast-southwest parallel to the general tend of the surrounding 

 gneisses. The full size is not revealed, but it measures several hun- 

 dred feet at least in that direction. Toward the border it becomes 

 finer grained. The country gneiss is a dark, banded variety, much of 

 it an amphibolite, and is intruded by aplite and pegmatite. Small 

 masses of the latter may be observed, which approximate the shape 

 of the larger body; they are irregularly bounded and contain patches 

 of the country gneiss that have been torn away from the walls. 



