The Collaborative International Dictionary of English v.0.48:

Oriskany \O*ris"ka*ny\, a. [From Oriskany, in New York.] (Geol.)
   Designating, or pertaining to, certain beds, chiefly
   limestone, characteristic of the latest period of the
   Silurian age.
   [1913 Webster]

   Oriskany period, a subdivision of the American Paleozoic
      system intermediate or transitional in character between
      the Silurian and Devonian ages. See Chart of Geology.
      [1913 Webster]