266 



Repoet of the State Geologist. 



There are abundant evidences, too, of crystallization after deposition. In 

 the richer parts of the beds lenticular layers of clear white or transparent 

 crystalline gypsum, an inch or two in thickness, occur, and the laminae above 

 are arched in conformity with them. They may be seen by the side of the 

 Split Rock road, a mile west of the " House of the Good Shepherd," and in 

 nearly every plaster quarry. The rock of this lower bed is sometimes called 

 " black plaster," as it is much darker colored, and this affects its commercial 

 value, though the actual difference in purity is said to be slight. 



The gypsum beds are exposed in many places in the vicinity of Fayette- 

 ville, in the town of Manlius, and south of Lyndon, in the town of Dewitt ; 

 also near Brighton, in Onondaga, and in the southern part of Geddes. They 

 are also exposed along both banks of Nine Mile creek, and on the line of the 

 Auburn branch of the New York Central railroad in Camillus. 



The first discovery of sulphate of lime or gypsum in the State of New 

 York, was made in 1792, by William Lyndsay, on Lot No. 90, in the town of 

 Camillus. In 1808, a stock company was organized and began the business of 

 quarrying and exporting gypsum, or land plaster, an industry that for many 

 years was second only to the manufacture of salt in its importance to Onon- 

 daga county. It has declined somewhat in late years, but recently discovered 

 processes of making prepared wall plaster, into which gypsum enters largely, 

 as the " Adamant," " Eureka " and " Paragon," promise to increase the demand 

 for it. 



When the gypsum is to be used as land plaster, it is quarried by the 

 ordinary methods used in soft rock, then broken with sledges into pieces con- 

 venient for handling, and hauled to the mill in carts. It is then broken in 

 stone-crushers or crackers, and ground fine by the use of mill stones. It is 

 then ready for use. For the manufacture of wall plaster it is calcined, becom- 

 ing, when pulverized, plaster-of-paris. 



The principal men or firms who quarry and grind plaster, are : Thos. 

 W. Sheedy, who has a mill at Fayetteville, and a quarry east of Fayetteville. 

 He also buys rock plaster. Output, 2,000 tons annually. Bangs & Gaynor, 

 Fayetteville, buy most of their stock from quarries in vicinity. Output, 5,000 

 tons. Lansing & Son, Dewitt, quarry two miles west of Fayetteville, mill on 

 the bank of the Erie canal. Output, 2,000 tons. F. M. Severance & Co., 

 Dewitt, quarry at the "Heard" beds, two miles west of Fayetteville. 

 Output 4,000 tons of rock plaster, shipped by canal out of county. 

 Robert Dunlop, mill one-half mile north of Jamesville, quarry one and 

 one-half miles northeast from mill; grinds and sells 2,000 tons annually. 



