THE MINING AND QUARRY INDUSTRY I907 39 



border. The Cocalico stone obtained in Lancaster county, Pa^ 

 and the Brush mountain stone, found in Montgomery co., Va.^ 

 are of similar character. In Ulster county the grit rests in un- 

 conformable position upon Hudson River shales and is overlain 

 in places by a red shale. It has generally been correlated vv^ith 

 the Oneida conglomerate of central New York to which it has 

 some physical resemblance, but recent investigations have shown 

 quite conclusively that it belongs higher up in the stratigraphic 

 series in the horizon of the Salina. Its thickness in Ulster 

 county ranges from 50 to 200 feet. 



The grit is composed of quartz pebbles of milky color sur- 

 rounded by a silicious matrix. The pebbles are of subangular 

 form and vary from a fraction of an inch to 2 inches in diameter. 

 The texture is an important factor in determining the value and 

 particular use of the finished millstones. 



The size of the stones marketed ranges from 15 to 90 inches. 

 The greater demand is for the smaller and medium sizes, with 

 diameters of 24, 30, 36, 42 and 48 inches. A pair of 30-inch mill- 

 stones commonly sells for $15, while $50 may be paid for a single 

 stone 60 inches in diameter. The largest sizes bring from $50 

 to $100. Besides the common type of millstones, disks are fur- 

 nished which are employed in a roll type of crusher known as a 

 chaser. The pavement of such crushers is also supplied by the 

 quarrymen, in the form of blocks. Quartz, feldspar and barytes 

 are commonly ground in chasers. 



Most of the Ulster county quarries are situated along the 

 northern edge of the Shawangunk mountain. Kyserike, St 

 Josen, Granite and Kerhonkson are the principal centers of the 

 industry while the distributing points include New Paltz and 

 Kingston in addition to those named. The industry is carried 

 on intermittently, many of the producers engaging in other occu- 

 pations during a part of the year. 



The market for millstones has been curtailed of late years by 

 the introduction of rolls, ball mills and other improved forms of 

 grinding machinery. The roller mill process has displaced the 

 old type of cereal mills, particularly in grinding wheat. The 

 small corn mills distributed throughout the southern states, how- 

 ever, still use millstones and furnish one of the important markets 

 for the New York quarries. A part of the jiroduct is sold also 

 to cement and talc manufacturers. 



Besides the uses that have been cminu'raUd. it would sconi 



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