Amongst the Pliocene Carnivores, we meet with true Bears (Ursus Arvernensis), Hyænas (such as Hyœna 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

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. 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.

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 Palæontology.' Owen.
(4)'British Fossil Mammals and Birds.' Owen.
(5)'Traité de Paléontologie.' Pictet.
(6)'Cours Elémentaire de Paléontologie.' 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., vol. xxvii. Prestwich.
(12)'On the Fluvio-marine Formations of the Isle of Wight'—Ibid., vol. ix. Edward Forbes.
(13)'Newer Tertiary Deposits of the Sussex Coast'—Ibid., vol. xiii. Godwin-Austen.
(14)'Kainozoic Formations of Belgium'—Ibid., vol. xxii. Godwin-Austen.
(15)'Tertiary Strata of Belgium and French Flanders'—Ibid., vol. viii. Lyell.
(16)'On Tertiary Leaf-beds in the Isle of Mull'—Ibid., vol. vii. The Duke of Argyll.
(17)'Newer Tertiaries of Suffolk and their Fauna'—Ibid., vol. xxvi. Ray Lankester.
(18)'Lower London Tertiaries of Kent'—Ibid., vol. xxii. Whitaker.
(19)"Guide to the Geology of London"—'Mem. Geol. Survey.' Whitaker.
(20)'Memoirs of the Geological Survey of Great Britain.'
(21)'Introductory Outline of the Geology of the Crag District' (Supplement to Crag Mollusca, Palæontographical Society). S. V. Wood, jun., and F. w. Harmer.
(22)"Tertiary Fluvio-marine Deposits of the Isle of Wight." Edward Forbes. Edited by Godwin-Austen; with Descriptions of the Fossils by Morris, Salter, and Rupert Jones—'Memoirs of the Geological Survey.'
(23)'Geological Excursions round the Isle of Wight.' Mantell.
(24)'Catalogue of British Fossils.' Morris.
(25)'Catalogue of Fossils in the Museum of Practical Geology.' Etheridge.
(26)'Monograph of the Crag Polyzoa' (Palæontographical Society). Busk.
(27)'Monograph of the Tertiary Brachiopoda' (Ibid.) Davidson.
(28)'Monograph of the Tertiary Malacostracous Crustacea' (Ibid.) Bell.
(29)'Monograph of the Tertiary Corals' (Ibid.) Milne-Edwards and Haime.
(30)'Supplement to the Tertiary Corals' (Ibid.) Martin Duncan.
(31)'Monograph of the Eocene Mollusca' (Ibid.) Fred. E. Edwards.
(32)'Monograph of the Eocene Mollusca' (Ibid.) Searles V. Wood.
(33)'Monograph of the Crag Mollusca' (Ibid.) Searles V. Wood.
(34)'Monograph of the Tertiary Entomostraca' (Ibid.) Rupert Jones.
(35)'Monograph of the Foraminifera of the Crag' (Ibid.) Rupert Jones, Parker, and H. B. Brady.
(36)'Monograph of the Radiaria of the London Clay' (Ibid.) Edward Forbes.
(37)'Monograph of the Cetacea of the Red Crag' (Ibid.) Owen.
(38)'Monograph of the Fossil Reptiles of the London Clay' (Ibid.) Owen and Bell.
(39)"On the Skull of a Dentigerous Bird from the London Clay of Sheppey"—'Quart. Journ. Geol. Soc.,' vol. xxix. Owen.
(40)'Ossemens Fossiles.' Cuvier.
(41)'Fauna Antiqua Sivalensis.' Falconer and Sir Proby Cautley.
(42)'Palæontological Memoirs.' Falconer.
(43)'Animaux Fossiles et Géologie de l'Attique.' Gaudry.
(44)"Principal Characters of the Dinocerata"—'American Journ. of Science and Arts,' vol. xi. Marsh.
(45)'Principal Characters of the Brontotheridæ' (Ibid.) Marsh.
(46)'Principal Characters of the Tillodontia' (Ibid.) Marsh.
(47)"Extinct Vertebrata of the Eocene of Wyoming"—'Geological Survey of Montana,' &c., 1872. Cope.
(48)"Ancient Fauna of Nebraska"—'Smithsonian Contributions to Knowledge,' vol. vi. Leidy.
(49)'Manual of Geology.' Dana.
(50)"Palæontology and Evolution" (Presidential Address to the Geological Society of London, 1870)—'Quart. Journ. Geol. Soc.,' vol. xxvi. Huxley.'
(51)'Mineral Conchology.' Sowerby.
(52)'Description des Coquilles Fossiles,' &c. Deshayes.
(53)'Description des Coquilles Tertiaires de Belgique.' Nyst.
(54)'Fossilen Polypen des Wiener Tertiär-beckens.' Reuss.
(55)'Palæontologische Studien über die älteren Tertiär-schichten der Alpen.' Reuss.
(56)'Land und Süss-wasser Conchylien der Vorwelt.' Sandberger.
(57)'Flora Tertiaria Helvetica.' Heer.
(58)'Flora Fossilis Arctica.' Heer.
(59)'Recherches sur le Climat et la Végétation du Pays Tertiaire.' Heer.
(60)'Fossil Flora of Great Britain.' Lindley and Hutton.
(61)'Fossil Fruits and Seeds of the London Clay.' Bowerbank.
(62)"Tertiary Leaf-beds of the Isle of Mull"—'Quart. Journ. Geol. Soc.,' vol. vii. Edward Forbes.
(63)'The Geology of England and Wales.' Horace B. Woodward.[25]

[Footnote 25: This work—published whilst these sheets were going through the press—gives to the student a detailed view of all the strata of England and Wales, with their various sub-divisions, from the base of the Palæozoic to the top of the Tertiary.]

CHAPTER XXI.

THE QUATERNARY PERIOD.