40 NEW YORK STATE MUSEUM 



probable that the Ulster county grit might be well adapted for 

 the lining of pebble mills, an application which has not been 

 attempted, hitherto, so far as known. Such mills are employed 

 quite extensively for fine grinding of feldspar and other hard 

 materials. They are usually lined with imported French rock 

 which is furnished in small blocks dressed to the required shape. 

 In its general freedom from iron or other coloring agents, the 

 grit fulfils one of the important requisites for such material, but 

 its wearing qualities under the severe conditions can not be de- 

 termined except by actual test. 



The production of millstones in 1907 amounted to a value of 

 $21,806, as compared with $22,442 in 1906 and $22,944 in 1905. 

 The production includes also the blocks and disks quarried and 

 sold for roll crushers. At one time the output of Ulster county 

 Avas valued at over $100,000 annually. 



MINERAL PAINT 



The term mineral paint is here used to designate the natural 

 mineral colors obtained by grinding an ore or rock. The ma- 

 terials suitable for this purpose that are found in New York 

 State include iron ore, shale, slate and ocher. 



For metallic paint and mortar colors some form of iron ore, 

 generally hematite or limonite, is commonly employed, but only 

 a few localities are known where the ore possesses the requisite 

 qualities of color and durability. The fossil hematite from the 

 Clinton formation is perhaps most widely used in this country. 

 The mines owned by C. A. Borst at Clinton, Oneida co., and 

 those of the Furnaceville Iron Co. at Ontario, Wayne co., supply 

 much of the crude material. The red hematite mined by the 

 Rossie Iron Ore Co. at Rossie, St Lawrence co., also yields a good 

 metallic paint. 



Mineral paint made from shale and slate is quite extensively 

 used for wooden structures. When there is a considerable per- 

 centage of iron oxids present, the shale and slate may be sold for 

 metallic paint. Their value depends largely upon the depth and 

 durability of their color; but the degree of natural fineness and 

 the amount of oil required in mixing must also be considered in 

 determining their utility. At Randolph, Cattaraugus co., beds 

 of green, brown and bluish shale occur in the Chemung forma- 

 tion. They are worked by the Elko Paint Co. In years past 

 red shale has been obtained in Herkimer county from the Vernon 



