Source : Webster's Revised Unabridged Dictionary (1913)

Medina epoch \Me*di"na ep"och\ [From Medina in New York.]
   (Geol.)
   A subdivision of the Niagara period in the American upper
   Silurian, characterized by the formations known as the Oneida
   conglomerate, and the Medina sandstone. See the Chart of
   {Geology}.