THE MINING AND QUARRY INDUSTRY I912 73 



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

 in the Rosendale district and in Schoharie and Onondaga counties. 

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

 The purer layers are employed in Onondaga county for lime-making. 

 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 prominent for its calcareous strata. Lime- 

 stones of this age are 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 Green- 

 port is obtained from Becraft mountain, an isolated area of lime- 

 stones 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. 



The Onondaga limestone, separated from the preceding by the 

 Oriskany sandstone, has a very wide distribution, outcropping 

 almost continuously from Buffalo, Erie county, eastward to Oneida 

 county and then southeasterly into Albany county, where the belt 

 curves to the south and continues through Greene, Ulster and 

 Orange counties to the Delaware river. It is in most places a bluish 

 gray, massive limestone with layers and disseminated nodules of 

 chert. The chert is usually more abundant in the upper beds. 

 The limestone finds use as building stone and the less siliceous ma- 

 terial, also, for lime-making. Quarries have been opened at Kings- 

 ton, Split Rock (near Syracuse), Auburn, Waterloo, Seneca Falls, 

 Leroy, Buffalo and other places. 



The Tully is the uppermost of the important limestone forma- 

 tions and likewise the most southerly one represented in the central 

 part of the State. Its line of outcrop extends from Ontario to 

 Madison county, intersecting most of the Finger Lakes. Its thick- 

 ness is not over ten feet, and on that account can not be worked 

 to advantage except under most favorable conditions of exposure. 

 For building stone it is quarried only locally and to a very limited 

 extent. It finds its principal use in portland cement manufacture, 

 being employed for that purpose by the Cayuga Lake Cement Co. 

 in its works at Portland Point, Tompkins county. 



