SANDSTONES 



389 



into the Oneonta sandstone horizon. Many of the quarries are 

 in the latter formation. The more western and northwestern and 

 higher quarries are in it ; and some of the Chenango county 

 quarries also. 



The Portage rocks in the western part of the State consist of 

 shales at the base ; then shales and flagstones ; and the Portage 

 sandstone at the top. In the last division thick beds with little 

 shale are marks of this horizon. The stone is generally fine- 

 grained. The quarries near Portage and near Warsaw are in it ; 

 also the quarries at Laona and Westfield in Chautauqua county. 



Although not of as great extent in its outcrop as the Hamilton 

 group the Portage rocks are developed to a thickness of several 

 hundred feet along the Genesee river at Mount Morris and at 

 Portage; and form a belt having a breadth of several miles 

 through Tompkins, Schuyler, Yates, Ontario and Livingston 

 counties, and thence west to Lake Erie." The formation is 

 capable of supplying an immense amount of good building stone 

 and flagstone throughout its undeveloped territory. 



Chemung Group. 

 The rocks of the Chemung group crop out in the southern tier 

 of counties, from Lake Erie eastward to the Susquehanna. The 

 shales are in excess of the sandstones in many outcrops, and there 

 is less good building stone than in the Portage horizon. The 

 variation in color and texture is necessarily great in the extensive 

 area occupied by the Chemung rocks, but the sandstones can be 

 described as thin-bedded, generally intercalated with shaly strata, 

 and of a light-gray color, often with a tinge of green or olive- 

 colored. The outcropping ledges weather to a brownish color. f 

 Owing to the shaly nature of muoh of the sandstone of the 

 Chemung group, the selection of stone demands care, and the 

 location of quarries where good stone may be found is attended 

 with the outlay of time and money, and with great chances of 

 possible failure. Quarries have been opened near the towns and 

 where there is a market for ordinary grades of common wall 

 stone, and also for cut stone, but the larger part of their product 



* Report of Prof. Hall above cited, pp 238-9. 



tProf . Hall's Report on Fourth District (cited above), pp. 251, 252. 



