4^ NI-:\V YORK STATK ML'SliUM 



wells of Oswego and Onondaga counties now supplying gas are 

 bottomed in the Trenton, though in many instances secondary con- 

 tributions are derived from the overlying Utica shale. Elsewhere, 

 as in Oneida and JcfYerson counties, these Hmestones have not 

 afforded any durable supply. 



The next higiier horizon of importance is at the base of the 

 Lower Siluric and includes the Medina sandstone and its eastern 

 representative, the ( )swcgo sandstone. The occurrence of pools 

 in this formation is of recent discovery, but they now yield a very 

 large portion of the production. The principal field opened since 

 1(890 is in Erie county beginning near Buffalo and extending east- 

 ward through the towns of Cheektowaga, Amherst, Lancaster, 

 Clarence, Alden and Newstead. A second field occurs south of 

 BufTalo between that city and Jewettville. The ^vells at Avon and 

 Caledonia, Livingston. co. are said to reach the Medina. In the last 

 two years large pools have been encountered in what is regarded 

 as the white Medina sandstone in northern Chautauqua county, 

 notably at Westfield and Silver Creek. The recent discoveries at 

 Pavilion, Genesee co. are likewise reported to be in that formation. 



The remaining formations of the Lower Siluric arc made up 

 mostly of shales and limestones. They appear to be relatively 

 poor reservoirs for gas. 



In the Devonic system practically all of the formations repre- 

 sented in western New York have been found to contain gas at 

 one or more localities. The most prolific, undoubtedly, are the 

 upper members, the Portage and Chemung shales and sandstones. 

 They arc tapped by numerous wells in Allegany, Cattaraugus and 

 Chautauqua counties. The principal gas supplies are derived from 

 southern Allegany and Cattaraugus counties, from the same fields 

 v.diich yield petroleum. Many of the wells yield both gas and oil. 

 and a part of the gas is consumed locally in operating the oil 

 pumps, while the remainder is run into pipe lines for distribution 

 in the neighboring cities and villages. The original wells put down 

 in the Lake Shore belt of Chautauqua county at Fredonia, Brock- 

 ton, Mayville and Ripley seem to have found the gas mainly in 

 the Chemung shales. The deeper wells that were drilled later en- 

 countered reservoirs at different horizons below the Chemung, as 

 far down as the Medina. The IMarcellus and Onondaga forma- 

 tions of the Devonic are considered by Bishop' to be the sources 

 of the gas at Gowanda, in northern Cattaraugus county. 



1 Oil and Gas in Southwe^ern New York. X'. Y. State Geol. 19th 

 An. Rep't. igci. p. 116. 



