MINERAL RESOURCES OF THE STATE OF NEW YORK I7I 



county, at the east end of Lake Ontario, is reached at 1425 feet 

 depth. At Central Square, farther south, it Hes 2415 feet from the 

 surface. At Utica granite is found at 1855 feet depth. In Onon- 

 daga county the basement is 3000 feet or more below the surface, 

 as shown by deep wells at Baldwinsville and Jordan. 



The thickness of the Paleozoic section in western New York 

 normally increases from north to south at the rate of from 50 to 100 

 feet to the mile, with allowance for the variations in the elevation 

 above sea level. This is the indicated dip of the Medina formation 

 as taken from records of a large number of wells distributed over 

 the central section to the south of the line of outcrop which lies 

 along the shore of Lake Ontario from Oswego county to the Niagara 

 river. 



Main gas horizons. Natural gas has been found over a wide 

 range of the Paleozoic formations that extend in general from the 

 Potsdam sandstone in the Cambrian to the higher Devonian strata 

 represented by the Chemung sandstone, and also probably includes 

 the basal Carboniferous which occupies a limited area in the extreme 

 southwestern part of the State as a northerly extension of the main 

 Appalachian belt. The largest and more permanent flows, however, 

 come from a few stratigraphic horizons, which are here given in 

 order of succession. 



GAS-BEARING STRATA DEVELOPED POOLS, BY COUNTIES 



Chemung and Portage sandstones Allegany, Cattaraugus, Chautauqua, 



Steuben 

 Marcellus shale Cattaraugus, Erie, Livingston, 



Ontario 



Onondaga limestone Cattaraugus, Erie 



Salina waterlime Cattaraugus, Erie 



Medina sandstone Cattaraugus, Chautauqua, Erie, 



Genesee, Livingston, Monroe, 



Ontario, Wyoming 

 Trenton limestone Niagara, Onondaga, Oswego, Oneida 



The Chemung and Portage are here classed together, as the 

 horizons that yield the gas have not been well defined as yet. Some 

 wells are known to give flows from both formations. In the southern 

 section of Allegany and Cattaraugus counties the productive strata 

 may include Carboniferous representatives, as in certain districts 

 there is a considerable thickness of these rocks above the Chemung 

 and the boundary can not be established from the well records. 

 In parts of Steuben, Allegany and Cattaraugus counties both oil 

 and gas are obtained within the Upper Devonian strata. In the 



