MINERAL RESOURCES OF THE STATE OF NEW YORK 1 73 



in the townships east and southeast of Buffalo during the few years 

 succeeding 1899. Then followed the discoveries along the lake belt 

 in Chautauqua county where shallow wells in the Devonian had 

 long been in use, the opening of additional wells in central and 

 southern Erie county, the development of the Pavilion field in south- 

 eastern Genesee county and of other fields in the adjoining territory. 

 There are doubtless important supplies in the Medina yet to be 

 tapped, for the sandstone underlies an extensive area. Its outcrop 

 extends from the vicinity of Oneida lake in central New York west 

 for 150 miles to the Niagara river which it crosses and continues 

 into Canada. Its extension on the dip, which is to the south, has 

 been followed in places as far as 25 to 50 miles from the outcrop, 

 and no doubt it underlies all of western New York between the 

 outcrop and the Pennsylvania line. The inclination averages around 

 40 feet to the mile for the first several miles south, but seems to 

 flatten in the middle part of the State so that the depth to the Medina 

 in the southern tier of counties is less than would be anticipated 

 in view of the dip near the outcrop. The Medina sandstone repre- 

 sents only a part of the entire formation which includes a great 

 mass of red and gray shales with their sandy layers that measures 

 fully 1000 feet thick in western New York. The sandstone occurs 

 above the main shale beds through a vertical range of 100 to 150 

 feet, terminated at the base by a 25-foot bed of gray sandstone 

 (Whirlpool sandstone). Below the main shales at the base of the 

 Medina occurs the Oswego sandstone, 75 feet thick in western New 

 York. This is also a possible horizon for natural gas. Most of 

 the pools in the Medina proper seem to be contained in the middle 

 and lower beds of sandstone and above the thick shales. 



The Trenton limestone, as the name is used in the natural gas 

 field, includes the assemblage of calcareous beds that lies just below 

 the Cincinnati shales and is composed of the Lowville, Black River 

 and Trenton stratigraphic units. The Trenton is developed in 

 the Champlain valley, along the Mohawk river to the south of the 

 Adirondacks, and in the Black River valley from which a broad 

 belt reaches west to the St Lawrence river and Lake Ontario. It 

 does not outcrop in western New York, but is exposed on the north 

 shore of Lake Ontario under which the beds extend to the south 

 side so as to be encountered in wells all the way from Oswego 

 county to the Niagara river. In this section a dip of about 40 

 feet to the mile is to be expected. On the west end in Niagara 

 and Erie counties the Trenton is credited by Bishop with a thickness 

 of 720 feet, mostly limestone. No important gas pools have been 



