

COMPOSITION, DISTRIBUTION, AND EXCAVATION OF GYPSUM. 21 



New Mexico. Though gypsum is known to occur in quantity at 

 many points, the only commercial development has been at Ancho, 

 where a piaster-mill is now in operation. 



New York. The gypsum in New York State occurs as rock gypsum 

 interbedded with shales and shaly limestones. Several gypsum beds, 

 separated by shales, usually occur in any given section. They are 

 lenticular in shape, but of such horizontal extent that in any given 

 quarry they are usually of practically uniform thickness. Those that 

 are worked vary from 4 to 10 feet in thickness in most of the quarries, 

 but at Fayetteville a 30-foot bed is exposed. The area in which the 

 gypsum-bearing formations are found as shown in the map, Fig. 3, 

 extends through the central part of the State, the productive portion 

 of the belt including parts of Madison, Onondaga, Cayuga, Ontario, 

 Genesee, Monroe, Livingston, and Erie counties. 



The most easterly points at which gypsum has been worked are in 

 Madison County, but the product there is small and is marketed locally 

 for use as land-plaster. In Onondaga County, at Marcellus, Fayetteville, 

 and other points, large quarries are operated, part of the product being 

 calcined and part ground for land-plaster. The quarries near Union 

 Springs, in Cayuga County, produce principally land-plaster, as do 

 those of Phillipsport, Gibson, and Victor, in Ontario County. The 

 gypsum from Mumford, Wheatland, Garbuttville, and Oakfield is used 

 chiefly for calcined plaster. 



Ohio. "The gypsum deposits of Ohio which are of economic 

 value consist of beds of rock gypsum occurring in the northwestern 

 part of the State. They have been known since the first settlements 

 were made on the northern shore of Sandusky Bay. The expo- 

 sures lie at about the level of the waters of the bay, in some places 

 rising a few feet above it. In addition to the deposits of economic 

 importance, gypsum is found in small pockets and isolated bodies 

 throughout the area of the Salina group, which occurs extensively in 

 northwestern Ohio. The deposits which are worked vary considerably 

 in thickness, ranging from a few inches up to 9 feet. On the north 

 shore of Sandusky Bay, in Portage Township, Ottawa County, 1500 

 to 2000 acres of land have been thoroughly prospected with a core- 

 drill, and it has been shown that there are from 150 to 200 acres of 

 workable gypsum. On the south shore of the bay, about 2J miles 

 northwest of the town of Castalia, drilling has shown the presence 

 of another area of workable gypsum, but no developments have 

 yet been undertaken. The location of these deposits is shown on 

 the accompanying map, Fig. 4. It is estimated that at the present 



