The Upper Allegheny. Above Oil City, Venango County the Allegheny itself is clear, and also forms a fine collecting ground for the zoologist. This is especially true for the fish fauna and the fauna of fresh-water mollusks. This good condition continues up to the New York state line in Warren County. Of the tributaries, Oil Creek is badly polluted at Oil City, where it falls into the Allegheny, but it is pure at its headwaters. The intermediate parts have not been studied by the writer, so that he cannot name the exact spot where the pollution begins. It is due chiefly to oil refineries. Tionesta Creek, in Forest County, is polluted by chemical refuse, at least where it enters the Allegheny; the upper parts have not been investigated. Brokenstraw Creek, in Warren County, is in a fair condition, but it belongs to the class of streams which improve during their course: its headwaters are polluted by refuse from tanneries at Cory in Erie County. Conewango Creek, in Warren County, which brings the outflow of Chautauqua Lake in New York, is good. The headwaters of the Allegheny in McKean and Potter Counties are generally good, but there are some tributaries which are polluted, for instance, Potato Creek, in McKean County (polluted by chemical factories). Where Potato Creek falls into the Allegheny is in a very bad condition, but its size is not sufficient to influence the Allegheny noticeably".

from "The Destruction of Fresh Water Fauna in Western PA", pp. 104-107. Dr. A. E. Ortmann. Reprinted from Proceedings of the American Philosophical Society, Vol. XLVIII, No. 191, 1909. Ortmann was Chief Zoologist, Carnegie Institute, Pittsburgh.