QUATERNARY  , in

geology, the time - division which embraces the Pleistocence and Holocene epochs, i.e. the later portion of the Cainozoic era, equivalent to the " Post-Pliocene " or " Post-Tertiary " of certain writers . The term was proposed by J . Desnoyers in 1829 to cover those formations which were formed just anterior to the present . There are other ways of regarding the Quaternary time . Sir A . Geikie (Text Book of Geology, 4th ed., 1903) divides it into an upper, post-glacial or Human period, and a lower, Pleistocene or Glacial period; but he subdivides the former into an Historic and a Prehistoric epoch, a scheme presenting difficulties, for the Palaeolithic or lower stage of prehistoric time cannot really be separated from the Pleistocene (q.v.) . E . Kayser (Formationskunde, 3rd. ed., 1906), who is in agreement with the definition accepted above, employs a nomenclature which is rarely adopted by British geologists; he divides the Quartarformation (Quartar) into a younger, modern epoch, the Alluvium, and an older epoch, the Pleistocene or Diluvium (= Glacial) . A. de Lapparent, on the other hand (Traite de geologie, 5th ed., 1906), treats the Era moderne or Quaternaire as a great time division equivalent in value to the Tertiary, Secondary, &c., which is so far represented only by a first epoch, the Pleistocene .