D defs.my
Entry 1 sense Webster, 1913

Medina epoch

/məd-īn'-ə ĕp'-ək/ · Me·di·na ep·och · IPA
01 A subdivision of the Niagara period in the American upper Silurian, characterized by the formations known as the Oneida conglomerate, and t…
  1. 1.
    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.(Geol.) See: Geology