w York State Museum Bulletin 



Q 



11 



N82X 



NH ered as second-class matter November 27, ipiS, at the Post Office at Albany, N. Y., 



under the act of August 24, 1912 



Published monthly by The University of the State of New York 



Nos. 203, 204 



ALBANY, N. Y. 



November and December 1917 



The University of the State of New York 

 New York State Museum 



John M. Clarke, Director 



HIGH-GRADE SILICA MATERIALS 

 FOR GLASS, REFRACTORIES AND ABRASIVES 



BY 



R. J. COLONY 



page 



Introduction 5 



Part I : The Poughquag quartzite 

 (Lower Cambrian) in West- 

 chester county 7 



Poughquag quartzite in Dutchess , 



county ; 9 



The Shawangunk conglomerate /^ 

 (Silurian). 



PAGE 



The Oriskany sandstone (Lower 



Devonian; ^ 14 



The Potsdam sandstone (Cam- 

 brian) 15 



The Oneida glass sand (Pleistocene) 20 

 art 2: Economic value of the 



material described 23 



Conclusions ' 29 



Mi2or-Jai9-isoo 



ALBANY 



THE UNIVERSITY OF THE STATE OF NEW YORK 



1919 



