THE MINING AND QUARRY INDUSTRY IQ12 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. 
