[Illustration:  Fig. 252.—­Molar tooth of Elephas antiquus, one-third of the natural size.  Pliocene and Post-Pliocene.]

Amongst the Pliocene Carnivores, we meet with true Bears (Ursus Arvernensis), Hyaenas (such as Hyoena Hipparionum), and genuine Lions (such as the Felis angustus of North America); but the most remarkable of the beasts of prey of this period is the great “Sabre-toothed Tiger” (Machairodus), species of which existed in the earlier Miocene, and survived to the later Post-Pliocene.  In this remarkable form we are presented with perhaps the most highly carnivorous type of all known beasts of prey.  Not only are the jaws shorter in proportion even than those of the great Cats of the present day, but the canine teeth (fig. 253) are of enormous size, greatly flattened so as to assume the form of a poignard, and having their margins finely serrated.  A part from the characters of the skull, the remainder of the skeleton, so far as known, exhibits proofs that the Sabre-toothed Tiger was extraordinarily muscular and powerful, and in the highest degree adapted for a life of rapine.  Species of Machairodus must have been as large as the existing Lion; and the genus is not only European, but is represented both in South America and in India, so that the geographical range of these predaceous beasts must have been very extensive.

[Illustration:  Fig. 253.—­A, Skull of Machairodus cultridens, without the lower jaw, reduced in size; B, Canine tooth of the same, one-half the natural size.  Pliocene, France.]

Lastly, we may note that the Pliocene deposits of Europe have yielded the remains of Monkeys (Quadrumana), allied to the existing Semnopitheci and Macaques.

LITERATURE.

The following list comprises a small selection of some of the more important and readily accessible works and memoirs relating to the Tertiary rocks and their fossils.  With few exceptions, foreign works relating to the Tertiary strata of the continent of Europe or their organic remains have been omitted:—­

 (1) ‘Elements of Geology.’  Lyell.
 (2) ‘Students’ Elements of Geology.’  Lyell.
 (3) ‘Manual of Palaeontology.’  Owen.
 (4) ‘British Fossil Mammals and Birds.’  Owen.
 (5) ‘Traite de Paleontologie.’  Pictet.
 (6) ‘Cours Elementaire de Paleontologie.’  D’Orbigny.
 (7) “Probable Age of the London Clay,” &c.—­’Quart.  Journ.  Geol. 
     Soc.,’ vol. iii.  Prestwich.
 (8) ’Structure and Probable Age of the Bagshot Sands’—­Ibid., vol.
     iii.  Prestwich.
 (9) ’Tertiary Formations of the Isle of Wight’—­Ibid., vol. ii. 
     Prestwich.
(10) ’Structure of the Strata between the London Clay and the
     Chalk,’ &c.—­Ibid., vols. vi., viii., and x.  Prestwich.
(11) ’Correlation of the Eocene Tertiaries of England, France,
     and Belgium’—­Ibid.,