ECONOMIC GEOLOGY 



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Cambrian age, quarried at Fort Ann in Washington county, haa 

 been ground for use as a wood filler. It has also been used at 

 the Troy Iron Works for lining Bessemer converters and for 

 similar refractory purposes. A similar rock is quarried for wood 

 filler at Billings, Dutchess county. 



At Ellenville, Ulster county, quarries and mills are operated 

 by the Crystal Sand Manufacturing Company. The product 

 which is called l glass sand' is obtained from the Shawangunk 

 grit, which is crushed very fine. Much of it is sent to the glass 

 works at Corning. 



Glass Sand 



Large glass sand deposits of Quaternary age occur at Durham- 

 ville, near Oneida lake. They are operated by William Williams. 

 The sand is not as white nor as fine as that from Ellenville, and 

 is used for the commoner grades of glassware. Much of it is 

 shipped to Lockport. The sand contains 97-97.5% Si. 02. 



Glass was formerly made at Sand Lake in Rensselaer County. 



An artificial glass sand made at Ellenville is described under 

 the previous head. 



Molding Sand 



Sand for molding is found in southern Albany County, near the 

 Hudson river, immedialtely below the surface soil. When this is 

 removed the sand is skimmed off to a depth of about six inches. 

 It is quite extensively shipped from the town of Bethlehem. 

 This is a Quaternary deposit. Near Poughkeepsie molding 

 sand is obtained from a silicious Potsdam limestone, which, in 

 decomposing, leaves a fine sand which has been found very satis- 

 factory for this purpose. 



Garnet 



Garnet is mined or quarried in New York state in and near 

 the valley of the upper Hudson river in Warren county on the 

 borders of the Adirondack region. It all appears to toe of the 

 common variety, Almandite, and occurs in a formation of crys- 

 talline limestone which appears to form the bedrock of the val- 

 ley in the vicinity of North Creek and Minerva and in gneissio 



