26 NEW YORK STATE MUSEUM 



bottoms of the small Adirondack lakes, those in Herkimer county 

 being best known, and are formed by the accumulation of the 

 minute silicious skeletons of organisms inhabiting the waters. They 

 attain a thickness up to 30 feet in White Lead lake from which the 

 present supply is obtained. The material is excavated and purified 

 by washing and settling in vats, after which it is compressed into 

 cakes for shipment. According to an analysis published in the 

 report for 1905 it contains about 86 per cent silica, 2 per cent or 

 less of iron oxid, alumina and lime, and about 12 per cent water. 



The earth is employed as an abrasive, particularly for polishing 

 of metal surfaces, as a substitute for quartz in the manufacture of 

 wood filler, and for various other purposes. The production re- 

 ported in 1907 was made by George W. Searles of Herkimer. 



EMERY 



The source of the small quantity of emery produced in the State 

 is near Peekskill, Westchester co. The material in crude state is a 

 rock, made up of corundum, spinel and magnetite chiefly, and rep- 

 resents a phase of the basic igneous intrusions of that vicinity which 

 are known as the Cortlandt series. The emery occurs as lenses and 

 bands grading off at the edges into the country rock which is usually 

 norite. The material was originally worked as an iron ore, but 

 unsuccessfully owing to its refractory nature from the presence of 

 so much alumina. In their geological relations the bodies resemble 

 the titaniferous magnetites of the Adirondacks, a similarity that is 

 strengthened by the fact that the analyses of the emery show a 

 small percentage of titanium. 



The production of emery in 1907 amounted to 1223 short tons, 

 valued at $13,057. This is a little less than the production for the 

 preceding year which totaled 1307 short tons valued at $13,870. 

 In 1905 the output was 1475 short tons valued at $12,452 and in 

 1904, 1 148 tons valued at $17,220. The valuation is based on the 

 material at the quarries, where it undergoes only hand sorting 

 and cobbing preparatory to shipment to outside points for grinding 

 and manufacture into emery wheels, stones, cloth, etc. 



The list of producers in 1907 includes the following: Blue 

 Corundum Mining Co., Easton, Pa., Keystone Emery Mills, Frank- 

 ford, Pa., Tanite Co., Stroudsburg, Pa., J. R. Lancaster, Peekskill, 

 and J. H. Bugby, Peekskill. With the exception of J. R. Lancaster 

 and J. H. Bugby, the companies mine the emery for their own use 

 in connection with manufacturing plants. 



