THE MINING AND QUARRY INDUSTRY I913 83 



of the Niagara group. The Qinton limestone has a variable im- 

 portance in the belt of Clinton strata that extends from Otsego 

 county a little south of the Mohawk river across the central and 

 western parts of the State on the line of Oneida lake and Rochester 

 to the Niagara river. East of Rochester the limestone is relatively 

 thin, usually shaly and split up into several layers, but on the west 

 end in Niagara county it becomes the predominant member and has 

 a more uniform character. Large quarries have been opened 

 recently at Pekin, Niagara county, for the supply of flux to the 

 blast furnaces of the Lackawanna Steel Co. at Buffalo. The upper 

 beds of bluish gray fossiliferous limestone from 10 to 12 feet thick 

 are the purest and analyze from 90 to 95 per cent calcium carbonate. 

 The Lockport is a magnesian limestone, in places a typical dolomite, 

 and is rather siliceous in the lower part. It outcrops in a continu- 

 ous belt, several miles wide, from Niagara Falls east to Onondaga 

 county and then with diminishing width across Madison county. 

 The upper layers are rather heavy and yield material suitable for 

 building purposes, road metal and lime. There are quarries around 

 Niagara Falls, Lockport and Rochester. It is worked to some extent 

 in Wayne, Onondaga and Madison counties. The Guelph, also 

 a dolomite, occupies a limited area in Monroe and Orleans counties 

 and is worked near Rochester. 



The Cayugan group includes among its members the Cobleskill, 

 Rondout and Manlius limestones, which are economically important. 

 They have furnished large quantities of material for the manu- 

 facture of natural cement, being the source of the cement rock in 

 the Rosendale dis-trict and in Schoharie and Onondaga counties. 

 The cement rock of Erie county is found in the Salina formation. 

 The Manlius limestone is used for portland cement in the eastern 

 part of the State. 



At the base of the Devonic system appears the Helderbergian 

 group which is very important for its calcareous strata. Limestones 

 of this age strongly developed along the Hudson river in Albany, 

 Columbia, Greene and Ulster counties. The Coeymans or lower 

 Pentamerus and the Becraft or upper Pentamerus limestones afford 

 material for building, road metal, lime and portland cement. The 

 limestone for the portland cement works at Hudson and Greenport 

 is obtained from Becraft mountain, an isolated area of limestones 

 belonging to the Manlius, Helderbergian and Onondaga formations. 

 The works at Howes Cave use both the Manlius and Coeymans 

 limestones. Extensive quarries are located also at Catskill, Rondout 

 and South Bethlehem, 



