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Being of the third formation, order, or rank; third; as, a tertiary use of a word. Trench.

Following, or more recent than, the Tertiary; Quaternary.

Earlier than Tertiary.

A period in the American eocene, the lowest in the tertiary age except the lignitic.

A group of large, extinct, herbivorous mammals, common in the Tertiary formation of the United States.

Barren regions, especially in the western United States, where horizontal strata (Tertiary deposits) have been often eroded into fantastic forms, and much intersected by canons, and where lack of wood, water, and forage increases the difficulty of traversing the country, whence the name, first given by the Canadian Fre…

A human skull reported, by Prof. J. D. Whitney, as found in 1886 in a Tertiary auriferous gravel deposit, lying below a bed of black lava, in Calaveras County, California. It is regarded as very doubtful whether the skull really belonged to the deposit in which it was found. If it did, it indicates an unprecedented ant…

Belonging to the most recent division of geological time, including the tertiary, or Age of mammals, and the Quaternary, or Age of man. [Written also cænozoic, cainozoic, kainozoic.] See Geology.

A genus of extinct mammals from the eocene tertiary of Europe and America. Its species varied in size between the tapir and rhinoceros, and were allied to those animals, but had short, plantigrade, five-toed feet, like the elephant.

A partially compacted bed of gravel mixed with shells, of the Tertiary age.

lly of a triclinic feldspar and pyroxene with magnetic iron; -- often limited to rocks pretertiary in age. It includes part of what was early called greenstone.

efly employed in teaching. -- Dominican tertiaries (the third order of St. Dominic). See Tertiary.

Pertaining to the first in time of the three subdivisions into which the Tertiary formation is divided by geologists, and alluding to the approximation in its life to that of the present era; as, Eocene deposits. -- n.

A series of strata, of the Middle Tertiary period, of France, abounding in shells, and used by Lyell as the type of his Miocene subdivision.

d schists overlying the true nummulitic formation in the Alps, and included in the Eocene Tertiary.

An extinct genus of Tertiary mammals allied to the horse, but three-toed, having on each foot a small lateral hoof on each side of the main central one. It is believed to be one of the ancestral genera of the Horse family.

he Rocky Mountain region, as in the Laramie Mountains, and formerly supposed to be of the Tertiary age, but now generally regarded as Cretaceous, or of intermediate and transitional character. It contains beds of lignite, often valuable for coal, and is hence also called the lignitic group. See Chart of Geology.…

Of or pertaining to the middle division of the Tertiary. -- n.

A soft Tertiary sandstone; -- applied to a rock occurring in Switzerland. See Chart of Geology.

recent than the Eocene, that is, including both the Miocene and Pliocene divisions of the Tertiary.