Exposures of the Oriskany formation were examined and samples collected between Monroe County, New York, and Monroe County, West Virginia. The lithologic character of the Oriskany and adjacent formations at ten localities is described. Samples were prepared by the usual methods of sedimentary petrography.

Two distinctly different heavy-mineral suites were found. The assemblage of tourmaline, zircon, rutile, leucoxene, indicative of derivation from sedimentary rocks, was characteristic of the Oriskany south of New York. The assemblage of garnet, hypersthene, kyanite, biotite, and amphiboles, in addition to those minerals just mentioned, is indicative of derivation from crystalline rocks as well as sedimentary rocks. This assemblage was confined to the Oriskany of New York.

The minerals indicate that south of New York the Oriskany sediments were derived from sedimentary formations exclusively, probably from Cambrian and Silurian sandstones, and that in the New York area they were derived directly from crystalline rocks of the Adirondacks as well as from sedimentary formations.