Quaternary

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 Quartarforniation (Quarter) 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.