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THE ANCIENT
LIFE-HISTORY
OF THE EARTH

Chapter 22:

THE POST-PLIOCENE PERIOD—Continued.


As regards the life of the Post-Pliocene period, we have, in the first place, to notice the effect produced throughout the Page 345 northern hemisphere by the gradual supervention of the Glacial period. Previous to this the climate must have been temperate or warm-temperate; but as the cold gradually came on, two results were produced as regards the living beings of the area thus affected. In the first place, all those Mammals which, like the Mammoth, the Woolly Rhinoceros, the Lion, the Hyæna, and the Hippopotamus, require, at any rate, moderately warm conditions, would be forced to migrate southwards to regions not affected by the new state of things. In the second place, Mammals previously inhabiting higher latitudes, such as the Reindeer, the Musk-ox, and the Lemming, would be enabled by the increasing cold to migrate southwards, and to invade provinces previously occupied by the Elephant and the Rhinoceros. A precisely similar, but more slowly-executed process, must have taken place in the sea, the northern Mollusca moving southwards as the arctic conditions of the Glacial period became established, whilst the forms proper to temperate seas receded. As regards the readily locomotive Mammals, also, it is probable that this process was carried on repeatedly in a partial manner, the southern and northern forms alternately fluctuating backwards and forwards over the same area, in accordance with the fluctuations of temperature which have been shown by Mr James Geikie to have characterised the Glacial period as a whole. We can thus readily account for the intermixture which is sometimes found of northern and southern types of Mammalia in the same deposits, or in deposits apparently synchronous, and within a single district. Lastly, at the final close of the arctic cold of the Glacial period, and the re-establishment of temperate conditions over the northern hemisphere, a reversal of the original process took place—the northern Mammals retiring within their ancient limits, and the southern forms pressing northwards and reoccupying their original domains.

The Invertebrate animals of the Post-Pliocene deposits require no further mention—all the known forms, except a few of the shells in the lowest beds of the formation, being identical with species now in existence upon the globe. The only point of importance in this connection has been previously noticed—namely, that in the true Glacial deposits themselves a considerable number of the shells belong to northern or Arctic types.

As regards the Vertebrate animals of the period, no extinct forms of Fishes, Amphibians, or Reptiles are known to occur, but we meet with both extinct Birds and extinct Mammals. The remains of the former are of great interest, as indicating Page 346 the existence during Post-Pliocene times, at widely remote points of the southern hemisphere, of various wingless, and for the most part gigantic, Birds. All the great wingless Birds of the order Cursores which are known as existing at the present day upon the globe, are restricted to regions which are either wholly or in great part south of the equator. Thus the true Ostriches are African; the Rheas are South American; the Emeus are Australian; the Cassowaries are confined to Northern Australia, Papua, and the Indian Archipelago; the species of Apteryx are natives of New Zealand; and the Dodo and Solitaire (wingless, though probably not true Cursores), both of which have been exterminated within historical times, were inhabitants of the islands of Mauritius and Rodriguez, in the Indian Ocean. In view of these facts, it is noteworthy that, so far as known, all the Cursorial Birds of the Post-Pliocene period should have been confined to the same hemisphere as that inhabited by the living representatives of the order. It is still further interesting to notice that the extinct forms in question are only found in geographical provinces which are now, or have been within historical times, inhabited by similar types. The greater number of the remains of these have been discovered in New Zealand, where there now live several species of the curious wingless genus Apteryx; and they have been referred by Professor Owen to several generic groups, of which Dinornis is the most important (fig. 257). Fourteen species of Dinornis have been described by the distinguished palæontologist just mentioned, all of them being large wingless birds of the type of the existing Ostrich, having enormously powerful hind-limbs adapted for running, but with the wings wholly rudimentary, and the breast-bone devoid of the keel or ridge which characterises this bone in all birds which fly. The largest species is the Dinornis giganteus, one of the most gigantic of living or fossil birds, the shank (tibia) measuring a yard in length, and the total height being at least ten feet. Another species, the Dinornis Elephantopus (fig. 257), though not standing more than about six feet in height, was of an even more ponderous construction—"the framework of the skeleton being the most massive of any in the whole class of Birds," whilst "the toe-bones almost rival those of the Elephant" (Owen). The feet in Dinornis were furnished with three toes, and are of interest as presenting us with an undoubted Bird big enough to produce the largest of the foot-prints of the Triassic Sandstones of Connecticut. New Zealand has now been so far explored, that it seems questionable if it can retain in its recesses any living example of Dinornis; but it Page 347 is certain that species of this genus were alive during the human period, and survived up to quite a recent date. Not only are the bones very numerous in certain localities, but they are found in Fig. 257
Fig. 257.—Skeleton of Dinornis elephantopus, greatly reduced. Post-Pliocene, New Zealand. (After Owen.)
the most recent and superficial deposits, and they still contain a considerable proportion of animal matter; whilst in some instances bones have been found with the feathers attached, or with the horny skin of the legs still adhering to them. Charred bones have been found in connection with native "ovens;" and the traditions of the Maories contain circumstantial accounts of gigantic wingless Birds, the "Moas," which were hunted both for their flesh and their plumage. Upon the whole, therefore, there can be no doubt Page 348 but that the Moas of New Zealand have been exterminated at quite a recent period—perhaps within the last century—by the unrelenting pursuit of Man,—a pursuit which their wingless condition rendered them unable to evade.

In Madagascar, bones have been discovered of another huge wingless Bird, which must have been as large as, or larger than, the Dinornis giganteus, and which has been described under the name of Æpiornis maximus. With the bones have been found eggs measuring from thirteen to fourteen inches in diameter, and computed to have the capacity of three Ostrich eggs. At least two other smaller species of Æpiornis have been described by Grandidier and Milne-Edwards as occurring in Madagascar; and they consider the genus to be so closely allied to the Dinornis of New Zealand, as to prove that these regions, now so remote, were at one time united by land. Unlike New Zealand, where there is the Apteryx, Madagascar is not known to possess any living wingless Birds; but in the neighbouring island of Mauritius the wingless Dodo (Didus ineptus) has been exterminated less than three hundred years ago; and the little island of Rodriguez, in the same geographical province, has in a similar period lost the equally wingless Solitaire (Pezophaps), both of these, however, being generally referred to the Rasores.

The Mammals of the Post-Pliocene period are so numerous, that in spite of the many points of interest which they present, only a few of the more important forms can be noticed here, and that but briefly. The first order that claims our attention is that of the Marsupials, the headquarters of which at the present day is the Australian province. In Oolitic times Europe possessed its small Marsupials, and similar forms existed in the same area in the Eocene and Miocene periods; but if size be any criterion, the culminating point in the history of the order was attained during the Post-Pliocene period in Fig. 258
Fig. 258.—Skull of Diprotodon Australis, greatly reduced. Post-Pliocene, Australia.
Australia. From deposits of this age there has been disentombed a whole series of remains of extinct, and for the most part gigantic, examples of this group of Quadrupeds. Not to speak of Wombats and Phalangers, two forms stand out prominently as representatives of the Post-Pliocene animals of Australia. One of these is Diprotodon (fig. 258), representing, with many differences, the well-known modern group of the Kangaroos. Page 349 In its teeth, Diprotodon shows itself to be closely allied to the living, grass-eating Kangaroos; but the hind-limbs were not so disproportionately long. In size, also, Diprotodon must have many times exceeded the dimensions of the largest of its living successors, since the skull measures no less than three feet in length. The other form in question is Thylacoleo (fig. 259), which is believed by Professor Owen to belong to the same group as the existing "Native Devil" (Dasyurus) of Van Diemen's Land, and therefore to have been flesh-eating and rapacious in its habits, though this view is not accepted by others. The principal feature in the skull of Thylacoleo is the presence, on each side of each jaw, of a single huge tooth, which is greatly compressed, and has a cutting edge. This tooth is regarded by Owen as corresponding to the great cutting tooth of the jaw of the typical Carnivores, but Professor Flower considers that Thylacoleo is rather related to the Kangaroo-rats. The size of the crown of the tooth in question is not less than two inches and a quarter; and whether carnivorous or not, it indicates an animal of a size exceeding that of the largest of existing Lions.

Fig. 259
Fig. 259.—Skull of Thylacoleo. Post-Pliocene, Australia. Greatly reduced. (After Flower.)

The order of the Edentates, comprising the existing Sloths, Ant-eaters, and Armadillos, and entirely restricted at the present day to South America, Southern Asia, and Africa, is one alike Page 350 singular for the limited geographical range of its members, their curious habits of life, and the well-marked peculiarities of their anatomical structure. South America is the metropolis of the existing forms; and it is an interesting fact that there flourished within Post-Pliocene times in this continent, and to some extent in North America also, a marvellous group of extinct Edentates, representing the living Sloths and Armadillos, but of gigantic size. The most celebrated of these is the huge Megatherium Cuvieri (fig. 260) of the South American Pampas. Fig. 260
Fig. 260.—Megatherium Cuvieri. Post-Pliocene, South America.
The Megathere was a colossal Sloth-like animal which attained a length of from twelve to eighteen feet, with bones more massive than those of the Elephant. Thus the thigh-bone is nearly thrice the thickness of the same bone in the largest of existing Elephants, its circumference at its narrowest point nearly equalling its total length; the massive bones of the shank (tibia and fibula) are amalgamated at their extremities; the heel-bone (calcaneum) is nearly half a yard in length; the haunch-bones (ilia) are from four to five feet across at their crests; and the bodies of the vertebræ at the root of the tail are from five to seven inches in diameter, from which it has been computed that the circumference of the tail at this part might have been from five to six feet. The length of the fore-foot is about a yard, and the toes are armed with powerful curved claws. It is known now that the Megathere, in spite of its enormous weight and ponderous construction, walked, like the existing Ant-eaters and Sloths, upon the outside edge of the fore-feet, with the claws more or less bent inwards Page 351 towards the palm of the hand. As in the great majority of the Edentate order, incisor and canine teeth are entirely wanting, the front of the jaws being toothless. The jaws, however, are furnished with five upper and four lower molar teeth on each side. These grinding teeth are from seven to eight inches in length, in the form of four-sided prisms, the crowns of which are provided with well-marked transverse ridges; and they continue to grow during the whole life of the animal. There are indications that the snout was prolonged, and more or less flexible; and the tongue was probably prehensile. From the characters of the molar teeth it is certain that the Megathere was purely herbivorous in its habits; and from the enormous size and weight of the body, it is equally certain that it could not have imitated its modern allies, the Sloths, in the feat of climbing, back downwards, amongst the trees. It is clear, therefore, that the Megathere sought its sustenance upon the ground; and it was originally supposed to have lived upon roots. By a masterly piece of deductive reasoning, however, Professor Owen showed that this great "Ground-Sloth" must have truly lived upon the foliage of trees, like the existing Sloths—but with this difference, that instead of climbing amongst the branches, it actually uprooted the tree bodily. In this tour de force, the animal sat upon its huge haunches and mighty tail, as on a tripod, and then grasping the trunk with its powerful arms, either wrenched it up by the roots or broke it short off above the ground. Marvellous as this may seem, it can be shown that every detail in the skeleton of the Megathere accords with the supposition that it obtained its food in this way. Similar habits were followed by the allied Mylodon (fig. 261), another of the great "Ground-Sloths," which inhabited South America during the Post-Pliocene period. In most respects, the Mylodon is very like the Megathere; but the crowns of the molar teeth are flat instead of being ridged. The nearly-related genus Megalonyx, unlike the Megathere, but like the Mylodon, extended its range northwards as far as the United States.

Just as the Sloths of the present day were formerly represented in the same geographical area by the gigantic Megatheroids, so the little banded and cuirassed Armadillos of South America were formerly represented by gigantic species, constituting the genus Glyptodon. The Glyptodons (fig. 262) differed from the living Armadillos in having no bands in their armour, so that they must have been unable to roll themselves up. It is rare at the present day to meet with any Page 352 Armadillo over two or three feet in length; but the length of the Glyptodon clavipes, from the tip of the snout to the end of the tail, was more than nine feet.

Fig. 261
Fig. 261.—Skeleton of Mylodon robustus. Post-Pliocene, South America.

There are no canine or incisor teeth in the Glyptodon, but there are eight molars on each side of each jaw, and the crowns of these are fluted and almost trilobed. The head is covered by a helmet of bony plates, and the trunk was defended by an armour of almost hexagonal bony pieces united by sutures, and Page 353 exhibiting special patterns of sculpturing in each species. The tail was also defended by a similar armour, and the vertebræ were mostly fused together so as to form a cylindrical bony rod. In addition to the above-mentioned forms, a number of other Edentate animals have been discovered by the researches of M. Lund in the Post-Pliocene deposits of the Brazilian bone-caves. Amongst these are true Ant-eaters, Armadillos, and Sloths, many of them of gigantic size, and all specifically or generically distinct from existing forms.

Fig. 262
Fig. 262.—Skeleton of Glyptodon clavipes. Post-Pliocene, South America.

Passing over the aquatic orders of the Sirenians and Cetaceans, we come next to the great group of the Hoofed Quadrupeds, the remains of which are very abundant in Post-Pliocene deposits both in Europe and North America. Amongst the Odd-toed Ungulates the most important are the Rhinoceroses, of which three species are known to have existed in Europe during the Post-Pliocene period. Two of these are the well-known Pliocene forms, the Rhinoceros Etruscus and the R. Megarhinus still surviving in diminished numbers; but the most famous is the Rhinoceros tichorhinus (fig. 263), or so-called "Woolly Rhinoceros." This species is known not only by innumerable bones, but also by a carcass, at the time of its discovery complete, which was found embedded in the frozen soil of Siberia towards the close of last century, and which was partly saved from destruction by the exertions of the naturalist Pallas. From this, we know that the Tichorhine Rhinoceros, like its associate the Mammoth, was provided with a coating of hair, and therefore was enabled to endure a more severe climate than any existing Page 354 species. Fig. 263
Fig. 263.—Skull of the Tichorhine Rhinoceros, the horns being wanting. One-tenth of the natural size. Post-Pliocene deposits of Europe and Asia.
The skin was not thrown into the folds which characterise most of the existing forms; and the technical name of the species refers to the fact that the nostrils were completely separated by a bony partition. The head carried two horns, placed one behind the other, the front one being unusually large. As regards its geographical range, the Woolly Rhinoceros is found in Europe in vast numbers north of the Alps and Pyrenees, and it also abounded in Siberia; so that it would appear to be a distinctly northern form, and to have been adapted for a temperate climate. It is not known to occur in Pliocene deposits, but it makes its first appearance in the Pre-Glacial deposits, surviving the Glacial period, and being found in abundance in Post-Glacial accumulations. It was undoubtedly a contemporary of the earlier races of men in Western Europe; and it may perhaps be regarded as being the actual substantial kernel of some of the "Dragons" of fable.

The only other Odd-toed Ungulate which needs notice is the so-called Equus fossilis of the Post-Pliocene of Europe. This made its appearance before the Glacial period, and appears to be in reality identical with the existing Horse (Equus caballus). True Horses also occur in the Post-Pliocene of North America; but, from some cause or another, they must have been exterminated before historic times.

Amongst the Even-toed Ungulates, the great Hippopotamus major of the Pliocene still continued to exist in Post-Pliocene times in Western Europe; and the existing Wild Boar (Sus scrofa), the parent of our domestic breeds of Pigs, appeared for the first time. The Old World possessed extinct representatives of its existing Camels, and lost types of the living Llamas inhabited South America. Amongst the Deer, the Post-Pliocene accumulations have yielded the remains of various living species, such as the Red Deer (Cervus elaphus), the Reindeer (Cervus tarandus), the Moose or Elk (Alces malchis), and the Roebuck (Cervus capreolus), together with a number of extinct forms. Among the latter, the great "Irish Elk" (Cervus megaceros) is justly celebrated both for its size and for the number and excellent preservation of its discovered remains. This extinct species (fig. 264) has been found principally in peat-mosses and Post-Pliocene lake-deposits, and is remarkable for the enormous size of the spreading antlers, which are widened out towards their extremities, and attain an expanse of over ten feet from tip to tip. It is not a genuine Elk, but is intermediate between the Reindeer and the Fallow-deer. Among the existing Deer Page 355 of the Post-Pliocene, the most noticeable is the Reindeer, an essentially northern type, existing at the present day in Northern Europe, and also (under the name of the "Caribou") in North America. When the cold of the Glacial period became established, this boreal species was enabled to invade Central and Western Europe in great herds, and its remains are found abundantly in cave-earths and other Post-Pliocene deposits as far south as the Pyrenees.

Fig. 264
Fig. 264—Skeleton of the "Irish Elk" (Cervus megaceros). Post-Pliocene, Britain.

Fig. 265
Fig. 265.—Skull of the Urns (Bos primigenius). Post-Pliocene and Recent. (After Owen.)

In addition to the above, the Post-Pliocene deposits of Europe and North America have yielded the remains of various Sheep and Oxen. One of the most interesting of the latter is Page 356 the "Urus" or Wild Bull (Bos primigenius, fig. 265), which, though much larger than any of the existing fossils, is believed to be specifically undistinguishable from the domestic Ox (Bos taurus), and to be possibly the ancestor of some of the larger European varieties of oxen. In the earlier part of its existence the Urus ranged over Europe and Britain in company with the Woolly Rhinoceros and the Mammoth; but it long survived these, and does not appear to have been finally exterminated till about the twelfth century. Another remarkable member of the Post-Pliocene Cattle, also to begin with an associate of the Mammoth and Rhinoceros, is the European Bison or "Aurochs" (Bison priscus). This "maned" ox formerly abounded in Europe in Post-Glacial times, and was not rare even in the later periods of the Roman empire, though much diminished in numbers, and driven back into the wilder and more inaccessible parts of the country. At present this fine species has been so nearly exterminated that it no longer exists in Europe save in Lithuania, where its preservation has been secured by rigid protective laws. Lastly, the Post-Pliocene deposits have yielded the remains of the singular living animal which is known as the Musk-ox or Musk-sheep (Ovibos moschatus). At the present day, the Musk-ox is an inhabitant of the "barren grounds" of Arctic America, and it is remarkable for the great length of its hair. It is, like the Reindeer, a Page 357 distinctively northern animal; but it enjoyed during the Glacial period a much wider range than it has at the present day, the conditions suitable for its existence being then extended over a considerable portion of the northern hemisphere. Thus remains of the Musk-Ox are found in greater or less abundance in Post-Pliocene deposits over a great part of Europe, extending even to the south of France; and closely-related forms are found in similar deposits in the United States.

Coming to the Proboscideans, we find that the Mastodons seem to have disappeared in Europe at the close of the Pliocene period, or at the very commencement of the Post-Pliocene. In the New World, on the other hand, a species of Mastodon (M. Americanus or M. Ohioticus) is found abundantly in deposits of Post-Pliocene age, from Canada to Texas. Very perfect skeletons of this species have been exhumed from morasses and swamps, and large individuals attained a length (exclusive of the tusks) of seventeen feet and a height of eleven feet, the tusks being twelve feet in length. Remains of Elephants are also abundant in the Post-Pliocene deposits of both the Old and the New World. Amongst these, we find in Europe the two familiar Pliocene species E. Meridionales and E. Antiquus still surviving, but in diminished numbers. With these are found in vast abundance the remains of the characteristic Elephant of the Post-Pliocene, the well-known "Mammoth" (Elephas primigenius), which is accompanied in North America by the nearly-allied, but more southern species, the Elephas Americanus. The Mammoth (fig. 266) is considerably larger than the largest of the living Elephants, the skeleton being over sixteen feet in length, exclusive of the tusks, and over nine feet in height. The tusks are bent almost into a circle, and are sometimes twelve feet in length, measured along their curvature. In the frozen soil of Siberia several carcasses of the Mammoth have been discovered with the flesh and skin still attached to the bones, the most celebrated of these being a Mammoth which was discovered at the beginning of this century at the mouth of the Lena, on the borders of the Frozen Sea, and the skeleton of which is now preserved at St Petersburg (fig. 266). From the occurrence of the remains of the Mammoth in vast numbers in Siberia, it might have been safely inferred that this ancient Elephant was able to endure a far more rigorous climate than its existing congeners. This inference has, however, been rendered a certainty by the specimens just referred to, which show that the Mammoth was protected against the cold by a thick coat of reddish-brown wool, some nine or ten inches long, interspersed with strong, coarse black Page 358 hair more than a foot in length. The teeth of the Mammoth (fig.267) are of the type of those of the existing Indian Elephant, and are found in immense numbers in certain localities.

Fig. 266
Fig. 266.—Skeleton of the Mammoth (Elephas primigenius). Portions of the integument still adhere to the head, and the thick skin of the soles is still attached to the feet. Post-Pliocene.

The Mammoth was essentially northern in its distribution, never passing south of a line drawn through the Pyrenees, the Alps, the northern shores of the Caspian, Lake Page 359 Baikal, Kamschatka, and the Stanovi Mountains (Dawkins). It occurs in the Pre-Glacial forest-bed of Cromer in Norfolk, Fig. 267
Fig. 267.—Molar tooth of the Mammoth (Elephas primigenius), upper jaw, right side, one-third of the natural size. a, Grinding surface; b, Side view. Post-Pliocene.
survived the Glacial period, and is found abundantly in Post-Glacial deposits in France, Germany, Britain, Russia in Europe, Asia, and North America, being often associated with the Reindeer, Lemming, and Musk-ox. That it survived into the earlier portion of the human period is unquestionable, its remains having been found in a great number of instances associated with implements of human manufacture; whilst in one instance a recognisable portrait of it has been discovered, carved on bone.

Amongst other Elephants which occur in Post-Pliocene deposits may be mentioned, as of special interest, the pigmy Elephants of Malta. One of these—the Elephas Melitensis, or so-called "Donkey-Elephant"—was not more than four and a half feet in height. The other—the Elephas Falconeri, of Busk—was still smaller, its average height at the withers not exceeding two and a half to three feet.

Whilst herbivorous animals abounded during the Post-Pliocene, we have ample evidence of the coexistence with them of a number of Carnivorous forms, both in the New and the Old World. The Bears are represented in Europe by at least three species, two of which—namely, the great Grizzly Bear (Ursus ferox) and the smaller Brown Bear (Ursus arctos)—are in existence at the present day. The third species is the Page 360 celebrated Cave-bear (Ursus spelœus, fig. 268), which is now extinct. The Cave-bear exceeded in its dimensions the largest of modern Bears; Fig. 268
Fig. 268.—Skull of Ursus spelpeus. Post-Pliocene, Europe. One-sixth of the natural size.
and its remains, as its name implies; have been found mainly in cavern-deposits. Enormous numbers of this large and ferocious species must have lived in Europe in Post-Glacial times; and that they survived into the human period, is clearly shown by the common association of their bones with the implements of man. They are occasionally accompanied by the remains of a Glutton (the Gulo spelœus), which does not appear to be really separable from the existing Wolverine or Glutton of northern regions (the Gulo luscus). In addition, we meet with the bones of the Wolf, Fox, Weasel, Otter, Badger, Wild Cat, Panther, Hyæna, and Lion, &c., together with the extinct Machairodus or "Sabre-toothed Tiger." The only two of these that deserve further mention are the Hyæna and the Lion. The Cave-hyæna (Hyœna spelœa, fig. 269) is regarded by high authorities as nothing more than a variety of the living Spotted Hyæna (H. Crocuta) of South Africa. This well-known species inhabited Britain and a considerable portion of Europe during a large part of the Post-Pliocene period; and its remains often occur in great abundance. Indeed, some caves, such as the Kirkdale Cavern in Yorkshire, were dens inhabited during long periods by these animals, and thus contain the remains of numerous individuals and of successive generations of Hyænas, together with innumerable gnawed and bitten bones of their prey. That the Cave-hyæna was a contemporary with Man in Western Europe during Post-Glacial times is shown beyond a doubt by the common association of its bones with human implements.

Page 361 Lastly, the so-called Cave-lion (Felis spelœa), long supposed to be a distinct species, has been shown to be nothing Fig. 269
Fig. 269.—Skull of Hyœna spelœa, one-fourth of the natural size. Post-Phocene, Europe.
more than a large variety of the existing Lion (Felis leo). This animal inhabited Britain and Western Europe in times posterior to the Glacial period, and was a contemporary of the Cave-hyæna, Cave-bear, Woolly Rhinoceros, and Mammoth. The Cave-lion also unquestionably survived into the earlier portion of the human period in Europe.

The Post-Pliocene deposits of Europe have further yielded the remains of numerous Rodents—such as the Beaver, the Northern Lemming, Marmots, Mice, Voles, Rabbits, &c.—together with the gigantic extinct Beaver known as the Trogontherium Cuvieri (fig. 270). The great Castoroides Ohioensis of the Fig. 270
Fig. 270.—Lower jaw of Trogontherium Cuvieri, one-fourth of the natural size. Post-Pliocene, Britain.
Post-Pliocene of North America is also a great extinct Beaver, which reached a length of about five feet. Lastly, the Brazilian bone-caves have yielded the remains of numerous Rodents of types now characteristic of South America, such as Guinea-pigs, Capybaras, tree-inhabiting Porcupines, and Coypus.

The deposits just alluded to have further yielded the remains of various Monkeys, such as Howling Monkeys, Squirrel Monkeys, and Marmosets, all of which belong to the group of Quadrumana which is now exclusively confined to the Page 362 South American continent—namely, the "Platyrhine" Monkeys.

We still have very briefly to consider the occurrence of Man in Post-Pliocene deposits; but before doing so, it will be well to draw attention to the evidence afforded by the Post-Pliocene Mammals as to the climate of Western Europe at this period. The chief point which we have to notice is, that a considerable revolution of opinion has taken place on this point. It was originally believed that the presence of such animals as Elephants, Lions, the Rhinoceros, and the Hippopotamus afforded an irrefragable proof that the climate of Europe must have been a warm one, at any rate during Post-Glacial times. The existence, also, of numbers of Mammoths in Siberia, was further supposed to indicate that this high temperature extended itself very far north. Upon the whole, however, the evidence is against this view. Not only is there great difficulty in supposing that the Arctic conditions of the Glacial period were immediately followed by anything warmer than a cold-temperate climate; but there is nothing in the nature of the Mammals themselves which would absolutely forbid their living in a temperate climate. The Hippopotamus major, though probably clad in hair, offers some difficulty—since, as pointed out by Professor Busk, it must have required a climate sufficiently warm to insure that the rivers were not frozen over in the winter; but it was probably a migratory animal, and its occurrence may be accounted for by this. The Woolly Rhinoceros and the Mammoth are known with certainty to have been protected with a thick covering of wool and hair; and their extension northwards need not necessarily have been limited by anything except the absence of a sufficiently luxuriant vegetation to afford them food. The great American Mastodon, though not certainly known to have possessed a hairy covering, has been shown to have lived upon the shoots of Spruce and Firs, trees characteristic of temperate regions—as shown by the undigested food which has been found with its skeleton, occupying the place of the stomach. The Lions and Hyænas, again, as shown by Professor Boyd Dawkins, do not indicate necessarily a warm climate. Wherever a sufficiency of herbivorous animals to supply them with food can live, there they can live also; and they have therefore no special bearing upon the question of climate. After a review of the whole evidence, Professor Dawkins concludes that the nearest approach at the present day to the Post-Pliocene climate of Western Europe is to be found in the climate of the great Siberian plains which stretch from the Altai Mountains to the Frozen Sea. "Covered Page 363 by impenetrable forests, for the most part of Birch, Poplar, Larch, and Pines, and low creeping dwarf Cedars, they present every gradation in climate from the temperate to that in which the cold is too severe to admit of the growth of trees, which decrease in size as the traveller advances northwards, and are replaced by the grey mosses and lichens that cover the low marshy 'tundras.' The maximum winter cold, registered by Admiral Von Wrangel at Nishne Kolymsk, on the banks of the Kolyma, is—65° in January. 'Then breathing becomes difficult; the Reindeer, that citizen of the Polar region, withdraws to the deepest thicket of the forest, and stands there motionless as if deprived of life;' and trees burst asunder with the cold. Throughout this area roam Elks, Black Bears, Foxes, Sables, and Wolves, that afford subsistence to the Jakutian and Tungusian fur-hunters. In the northern part countless herds of Reindeer, Elks, Foxes, and Wolverines make up for the poverty of vegetation by the rich abundance of animal life. 'Enormous flights of Swans, Geese, and Ducks arrive in the spring, and seek deserts where they may moult and build their nests in safety. Ptarmigans run in troops amongst the bushes; little Snipes are busy along the brooks and in the morasses; the social Crows seek the neighbourhood of new habitations; and when the sun shines in spring, one may even sometimes hear the cheerful note of the Finch, and in autumn that of the Thrush.' Throughout this region of woods, a hardy, middle-sized breed of horses lives under the mastership and care of man, and is eminently adapted to bear the severity of the climate.... The only limit to their northern range is the difficulty of obtaining food. The severity of the winter through the southern portion of this vast wooded area is almost compensated for by the summer heat and its marvellous effect on vegetation."—(Dawkins, 'Monograph of Pleistocene Mammalia.')

Finally, a few words must be said as to the occurrence of the remains of Man in Post-Pliocene deposits. That Man existed in Western Europe and in Britain during the Post-Pliocene period, is placed beyond a doubt by the occurrence of his bones in deposits of this age, along with the much more frequent occurrence of implements of human manufacture. At what precise point of time during the Post-Pliocene period he first made his appearance is still a matter of conjecture. Recent researches would render it probable that the early inhabitants of Britain and Western Europe were witnesses of the stupendous phenomena of the Glacial period; but this cannot be said to have been demonstrated. That Man existed in these Page 364 regions during the Post-Glacial division of Post-Pliocene time cannot be doubted for a moment. As to the physical peculiarities of the ancient races that lived with the Mammoth and the Woolly Rhinoceros, little is known compared with what we may some day hope to know. Such information as we have, however, based principally on the skulls of the Engis, Neanderthal, Cro-Magnon, and Bruniquel caverns, would lead to the conclusion that Post-Pliocene Man was in no respect inferior in his organisation to, or less highly developed than, many existing races. All the known skulls of this period, with the single exception of the Neanderthal cranium, are in all respects average and normal in their characters; and even the Neanderthal skull possessed a cubic capacity at least equal to that of some existing races. The implements of Post-Pliocene Man are exclusively of stone or bone; and the former are invariably of rude shape and undressed. These "palæolithic" tools (Gr. palaios; ancient; lithos, stone) point to a very early condition of the arts; since the men of the earlier portion of the Recent period, though likewise unacquainted with the metals, were in the habit of polishing or dressing the stone implements which they fabricated.

It is impossible here to enter further into this subject; and it would be useless to do so without entering as well into a consideration of the human remains of the Recent period—a period which lies outside the province of the present work. So far as Post-Pliocene Man is concerned, the chief points which the palæontological student has to remember have been elsewhere summarised by the author as follows:—

1. Man unquestionably existed during the later portion of what Sir Charles Lyell has termed the "Post-Pliocene" period. In other words, Man's existence dates back to a time when several remarkable Mammals, previously mentioned, had not yet become extinct; but he does not date back to a time anterior to the present Molluscan fauna.

2. The antiquity of the so-called Post-Pliocene period is a matter which must be mainly settled by the evidence of Geology proper, and need not be discussed here.

3. The extinct Mammals with which man coexisted in Western Europe are mostly of large size, the most important being the Mammoth (Elephas primogenius), the Woolly Rhinoceros (Rhinoceros tichorhinus), the Cave-lion (Felis spelœa), the Cave-hyæna(Hyœna spelœa), and the Cave-bear (Ursus spelœus). We do not know the causes which led to the extinction of these Mammals; but we know that hardly any Mammalian species has become extinct during the historical period.

Page 365 4. The extinct Mammals with which man coexisted are referable in many cases to species which presumably required a very different climate to that now prevailing in Western Europe. How long a period, however, has been consumed in the bringing about of the climatic changes thus indicated, we have no means of calculating with any approach to accuracy.

5. Some of the deposits in which the remains of man have been found associated with the bones of extinct Mammals, are such as to show incontestably that great changes in the physical geography and surface-configuration of Western Europe have taken place since the period of their accumulation. We have, however, no means at present of judging of the lapse of time thus indicated except by analogies and comparisons which may be disputed.

6. The human implements which are associated with the remains of extinct Mammals, themselves bear evidence of an exceedingly barbarous condition of the human species. Post-Pliocene or "Palæolithic" Man was clearly unacquainted with the use of any of the metals. Not only so, but the workmanship of these ancient races was much inferior to that of the later tribes, who were also ignorant of the metals, and who also used nothing but weapons and tools of stone, bone, &c.

7. Lastly, it is only with the human remains of the Post-Pliocene period that the palæontologist proper has to deal. When we enter the "Recent" period, in which the remains of Man are associated with those of existing species of Mammals, we pass out of the region of pure palæontology into the domain of the Archæologist and the Ethnologist.

LITERATURE.

The following are some of the principal works and memoirs to which the student may refer for information as to the Post-Pliocene deposits and the remains which they contain, as well as to the primitive races of mankind:—

(1) 'Elements of Geology.' Lyell.
(2) 'Antiquity of Man.' Lyell.
(3) 'Palæontological Memoirs.' Falconer.
(4) 'The Great Ice-age.' James Geikie.
(5) 'Manual of Palæontology.' Owen.
(6) 'British Fossil Mammals and Birds.' Owen.
(7) 'Cave-Hunting.' Boyd Dawkins.
(8) 'Prehistoric Times.' Lubbock.
(9) 'Ancient Stone Implements.' Evans.
(10) 'Prehistoric Man.' Daniel Wilson.
(11) 'Prehistoric Races of the United States.' Foster.
(12) 'Manual of Geology.' Dana.
Page 366 (13) 'Monograph of Pleistocene Mammalia' (Palæontographical Society). Boyd Dawkins and Sanford.
(14) 'Monograph of the Post-Tertiary Entomostraca of Scotland, &c., with an Introduction on the Post-Tertiary Deposits of Scotland' (Ibid.) G. S. Brady, H. W. Crosskey, and D. Robertson.
(15) "Reports on Kent's Cavern"—'British Association Reports.' Pengelly.
(16) "Reports on the Victoria Cavern, Settle"—'British Association Reports.' Tiddeman.
(17) 'Ossemens Fossiles.' Cuvier.
(18) 'Reliquiæ Diluvianæ.' Buckland.
(19) "Fossil Mammalia"—'Zoology of the Voyage of the Beagle.' Owen.
(20) 'Description of the Tooth and Part of the Skeleton of the Glyptodon.' Owen.
(21) "Memoir on the Extinct Sloth Tribe of North America"—'Smithsonian Contributions to Knowledge.' Leidy.
(22) "Report on Extinct Mammals of Australia"—'British Association,' 1844. Owen.
(23) 'Description of the Skeleton of an Extinct Gigantic Sloth (Mylodon robtutus).' Owen.
(24) "Affinities and Probable Habits of Thylacoleo"—'Quart. Journ. Geol. Soc.,' vol. xxiv. Flower.
(25) 'Prodromus of the Palæontology of Victoria.' M'Coy.
(26) 'Les Ossemens Fossiles des Cavernes de Liège.' Schmerling.
(27) 'Die Fauna der Pfahlbauten in der Schweiz.' Rütimeyer.
(28) "Extinct and Existing Bovine Animals of Scandinavia"—'Annals of Natural History,' ser. 2, vol. iv., 1849. Nilsson.
(29) 'Man's Place in Nature.' Huxley.
(30) 'Les Temps Antéhistoriques en Belgique.' Dupont.
(31) "Classification of the Pleistocene Strata of Britain and the Continent"—'Quart. Journ. Geol. Soc.,' vol. xxviii. Boyd Dawkins.
(32) 'Distribution of the Post-Glacial Mammalia' (Ibid.), vol. xxv. Boyd Dawkins.
(33) 'On British Fossil Oxen' (Ibid.), vols. xxii. and xxiii. Boyd Dawkins.
(34) 'British Prehistoric Mammals' (Congress of Prehistoric Archæology, 1868). Boyd Dawkins.
(35) 'Reliquiæ Aquitanicæ.' Lartet and Christy.
(36) 'Zoologie et Paléontologie Françaises.' Gervais.
(37) 'Notes on the Post-Pliocene Geology of Canada.' Dawson.
(38) "On the Connection between the existing Fauna and Flora of Great Britain and certain Geological Changes"—'Mem. Geol. Survey.' Edward Forbes.
(39) 'Cavern-Researches.' M'Enery. Edited by Vivian.
(40) "Quaternary Gravels"—'Quart. Journ. Geol. Soc.,' vol. xxv. Tylor.


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