D defs.my
Entry 1 sense Webster, 1913

Hamilton period

/(hăm"ĭl*tŭn pē"rĭ*ŭd)/ · Ham·il·ton pe·ri·od · IPA
01 A subdivision of the Devonian system of America; -- so named from Hamilton, Madison Co., New York. It includes the Marcellus, Hamilton, and…
  1. 1.
    A subdivision of the Devonian system of America; -- so named from Hamilton, Madison Co., New York. It includes the Marcellus, Hamilton, and Genesee epochs or groups. See the Chart of Geology.(Geol.) See: Geology