Q 



York State Museum Bulletin 



s second-class matter November 27, IQI5, at the Post Office at Albany, N. Y., 

 under the act of August 24, 1912 



I ablished 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 

 ?OR GLASS, REFRACTORIES AND ABRASIVES 



BY 



R. J. COLONY 



Introduction 



Part i : The Poughquag quartzite 



(Lower Cambrian) in West- 



chester county 



Poughquag quartzite in Dut chess 



county 



The Shawangunk conglomerate 



(Silurian) 



PAGE 



5 



PAGE 



The Oriskany sandstone (Lower 



Devonian; i , 



The Potsdam sandstone (Cam- 

 brian) 15 



The Oneida glass sand (Pleistocene) 2 o 

 Part 2: Economic value of thr 



material described 



Conclusions 29 



Index ^i 



ALBANY 



THE UNIVERSITY OF THE STATE OP NEW YORK 

 1919 



1500 



