To what era in the complicated history of Kent’s Hole is this animal to be assigned? The more ancient, or the more modern? The evidence on this point is, to a certain extent, contradictory. On the one hand it is a pleiocene species, belonging to a group of animals that inhabited Europe before the lowering of the temperature caused the invasion of the arctic mammalia from the north and the east: it is moreover of a distinctly southern type. In the teeth marks on the incisors, Figs. 103, 104, 105, as well as on the canines, we have unmistakeable traces of the presence of the hyæna; and since the spotted hyæna abounds in the cave, to its teeth the marks in question may probably be referred. It seems, therefore, probable that the animal inhabited Devonshire during an early stage of the pleistocene period, before the arctic invaders had taken full possession of the valley of the English Channel, and of the low grounds which now lie within the 100-fathom line off the Atlantic shore of Western France. There must necessarily have been a swinging to and fro of animal life over the great, fertile low-lying region, which is now submerged (see Map, Fig. 126); and before the temperature of France had been sufficiently lowered to exterminate or drive out the southern forms, it is most natural to suppose that in warm seasons some of the southern mammalia would find their way northwards, and especially a formidable carnivore such as the machairodus. The extreme rarity of its remains forbids the hypothesis that it was a regular inhabitant of Britain during the pleistocene age. [Illustration: FIGS. 103, 104, 105.--Incisors of Machairodus, Kent’s Hole (1/1). (MacEnery.)[215]] On the other hand, the recent discovery of a second incisor in the uppermost portion of the cave-earth, in July 1872, in the same condition as the remains usually found, and associated with the bones and teeth of hyæna, horse, and bear, is considered by Sir Charles Lyell and Mr. Pengelly proof of the animal having lived during the deposition of the later cave-earth, or in the later stage of the pleistocene. The condition of a bone, however, is a very fallacious guide to its antiquity, and although the fragments of the older contents of the cave are in a different mineral state, it is improbable that the ossiferous contents of so large a cave should have been mineralized exactly in the same way. Nor is an appeal to its perfect state conclusive, since several teeth of bear, which I have examined from the breccia, are equally perfect.