CHAPTER XIII.

CLOSE OF THE POST-PLIOCENE, AND ADVENT OF MAN. (_Continued._)

Turning from these difficult questions of time, we may now look at the assemblage of land-animals presented by the Post-glacial period. Here, for the first time in the great series of continental elevations and depressions, we find the newly-emerging land peopled with familiar forms. Nearly all the modern European animals have left their bones in the clays, gravels, and cavern deposits which belong to this period; but with them are others either not now found within the limits of temperate Europe, or altogether extinct. Thus the remarkable fact comes out, that the uprising land was peopled at first with a more abundant fauna then that which it now sustains, and that many species, and among these some of the largest and most powerful, have been weeded out, either before the advent of man or in the changes which immediately succeeded that event. That in the Post-glacial period so many noble animal species should have been overthrown in the struggle for existence, without leaving any successors, at least in Europe, is one of the most remarkable phenomena in the history of life on our planet.

According to. Pictet,[AQ] the Post-glacial beds of Europe afford ninety-eight species of mammals, of which fifty-seven still live there, the remainder being either locally or wholly extinct. According to Mr. Boyd Dawkins,[AR] in Great Britain about twelve Pliocene species survived the Glacial period, and reappeared in the British Islands in the Post-glacial. To these were added forty-one species making in all fifty-three, whose remains are found in the gravels and caves of the latter period. Of these, in the Modern period twenty-eight, or rather more then one-half, survive, fourteen are wholly extinct, and eleven are locally extinct.

[AQ] Palæontologie.

[AR] "Journal of Geological Society," and Palæontographical Society's publications.

Among the extinct beasts, were some of very remarkable character. There were two or more species of elephant, which seem in this age to have overspread, in vast herds, all the plains of Northern Europe and Asia; and one of which we know, from the perfect specimen found embedded in the frozen soil of Siberia, lived till a very modern period; and was clothed with long hair and fur, fitting it for a cold climate. There were also three or four species of rhinoceros, one of which at least (the _R. Tichorhinus_) was clad with wool like the great Siberian mammoth. With these was a huge hippopotamus (_H. major_), whose head-quarters would, however, seem to have been farther south then England, or which perhaps inhabited chiefly the swamps along the large rivers running through areas now under the sea. The occurrence of such an animal shows an abundant vegetation, and a climate so mild, that the rivers were not covered with heavy ice in winter; for the supposition that this old hippopotamus was a migratory animal seems very unlikely. Another animal of this time, was the magnificent deer, known as the Irish elk; and which perhaps had its principal abode on the great plain which is now the Irish Sea. The terrible machairodus, or cymetar-toothed tiger, was continued from the Pliocene; and in addition to species of bear still living, there was a species of gigantic size, probably now extinct, the cave bear. Evidences are accumulating, to show that all or nearly all these survived until the human period.

If we turn now to those animals which are only locally extinct, we meet with some strange, and at first sight puzzling anomalies. Some of these are creatures now limited to climates much colder then that of Britain. Others now belong to warmer climates. Conspicuous among the former are the musk-sheep, the elk, the reindeer, the glutton, and the lemming. Among the latter, we see the panther, the lion, and the Cape hyena. That animals now so widely separated as the musk-sheep of Arctic America and the hyena of South Africa, could ever have inhabited the same forests, seems a dream of the wildest fancy. Yet it is not difficult to find a probable solution of the mystery. In North America, at the present day, the puma, or American lion, comes up to the same latitudes with the caribou, or reindeer, and moose; and in Asia, the tiger extends its migrations into the abodes of boreal animals in the plains of Siberia. Even in Europe, within the historic period, the reindeer inhabited the forests of Germany; and the lion extended its range nearly as far northward. The explanation lies in the co-existence of a densely wooded country with a temperate climate; the forests affording to southern animals shelter from the cold or winter; and equally to the northern animals protection from the heat of summer. Hence our wonder at this association of animals of diverse habitudes as to climate, is merely a prejudice arising from the present exceptional condition of Europe. Still it is possible that changes unfavourable to some of these animals, were in progress before the arrival of man, with his clearings and forest fires and other disturbing agencies. Even in America, the megalonyx, or gigantic sloth, the mammoth, the mastodon, the fossil horse, and many other creatures, disappeared before the Modern period; and on both continents the great Post-glacial subsidence or deluge may have swept away some of the species. Such a supposition seems necessary to account for the phenomena of the gravel and cave deposits of England, and Cope has recently suggested it in explanation of similar storehouses of fossil animals in America.[AS]

[AS] Proceedings of the American Philosophical Society, April 1871.

Among the many pictures which this fertile subject calls up, perhaps none is more curious then that presented by the Post-glacial cavern deposits. We may close our survey of this period with the exploration of one of these strange repositories; and may select Kent's Hole at Torquay, so carefully excavated and illumined with the magnesium light of scientific inquiry by Mr. Pengelly and a committee of the British Association.

The somewhat extensive and ramifying cavern of Kent's Hole is an irregular excavation, evidently due partly to fissures in limestone rock, and partly to the erosive action of water enlarging such fissures into chambers and galleries. At what time it was originally cut we do not know, but it must have existed as a cavern at the close of the Pliocene or beginning of the Post-pliocene period, since which time it has been receiving a series of deposits which have quite filled up some of its smaller branches.

First and lowest, according to Mr. Pengelly, is a "breccia" or mass of broken and rounded stones, with hardened red clay filling the interstices. Most of the stones are of the rock which forms the roof and walls of the cave, but many, especially the rounded ones, are from more distant parts of the surrounding country. In this mass, the depth of which is unknown, are numerous bones, all of one kind of animal, the cave bear, a creature which seems to have lived in Western Europe from the close of the Pliocene down to the modern period. It must have been one of the earliest and most permanent tenants of Kent's Hole at a time when its lower chambers were still filled with water. Next above the breccia is a floor of "stalagmite" or stony carbonate of lime, deposited from the drippings of the roof, and in some places three feet thick. This also contains bones of the cave bear, deposited when there was less access of water to the cavern. Mr. Pengelly infers the existence of man at this time from a single flint flake and a single flint chip found in these beds; but mere flakes and chips of flint are too often natural to warrant such a conclusion. After the old stalagmite floor above mentioned was formed, the cave again received deposits of muddy water and stones; but now a change occurs in the remains embedded. This stony clay, or "cave earth" has yielded an immense quantity of teeth and bones, including those of the elephant, rhinoceros, horse, hyena, cave bear, reindeer, and Irish elk. With these were found weapons of chipped flint, and harpoons, needles, and bodkins of bone, precisely similar to those of the North American Indians and other rude races. The "cave earth" is four feet or more in thickness, It is not stratified, and contains many fallen fragments of rock, rounded stones, and broken pieces of stalagmite. It also has patches of the excrement of hyenas, which the explorers suppose to indicate the temporary residence of these animals; and in one spot, near the top, is a limited layer of burnt wood, with remains which indicate the cooking and eating of repasts of animal food by man. It is clear that when this bed was formed the cavern was liable to be inundated with muddy water, carrying stones and other heavy objects, and breaking up in places the old stalagmite floor. One of the most puzzling features, especially to those who take an exclusively uniformitarian view, is, that the entrance of water-borne mud and stones implies a level of the bottom of the water in the neighbouring valleys of about 100 feet above its present height. The cave earth is covered by a second crust of stalagmite, less dense and thick then that below, and containing only a few bones, which are of the same general character with those below, but include a fragment of a human jaw with teeth. Evidently, when this stalagmite was formed, the influx of water-borne materials had ceased, or nearly so; but whether the animals previously occupying the country still continued in it, or only accidental bones, etc., were introduced into the cave or lifted from the bed below, does not appear.

The next bed marks a new change. It is a layer of black mould from three to ten inches thick. Its microscopic structure does not seem to have been examined; but it is probably a forest soil, introduced by growth, by water, by wind, and by ingress of animals, at a time when the cave was nearly in its present state, and the surrounding country densely wooded. This bed contains bones of animals, all of them modern, and works of art ranging from the old British times before the Roman invasion up to the porter-bottles and dropped halfpence of modern visitors. Lastly, in and upon the black mould are many fallen blocks from the roof of the cave.

There can be no doubt that this cave and the neighbouring one of Brixham have done very much to impress the minds of British geologists with ideas of the great antiquity of man, and they have, more then any other Post-glacial monuments, shown the persistence of some animals now extinct up to the human age. Of precise data for determining time, they have, however, given nothing. The only measures which seed to have been applied, namely, the rate of growth of stalagmite and the rate of erosion of the neighbouring valleys, are, from the very sequence of the deposits, obviously worthless; and the only apparently available constant measure, namely, the fall of blocks from the roof, seems not yet to have been applied. We are therefore quite uncertain as to the number of centuries involved in the filling of this cave, and must remain so until a surer system of calculation is adopted. We may, however, attempt to sketch the series of events which it indicates.

The animals found in Kent's Hole are all "Post-glacial." They therefore inhabited the country after it rose from the great Glacial submergence. Perhaps the first colonists of the coasts of Devonshire in this period were the cave bears, migrating on floating ice, and subsisting, like the Arctic bear, and the black bears of Anticosti, on fish, and on the garbage cast up by the sea. They found Kent's Hole a sea-side cavern, with perhaps some of its galleries still full of water, and filling with, breccia, with which the bones of dead bears became mixed. As the land rose, these creatures for the most part betook themselves to lower levels, and in process of time the cavern stood upon a hill-side, perhaps several hundreds of feet above the sea; and the mountain torrents, their beds not yet emptied of glacial detritus, washed into it stones and mud and carcases of animals of many species which had now swarmed across the plains elevated out of the sea, and multiplied in the land. This was the time of the cave earth; and before its deposit was completed, though how long before, a confused and often-disturbed bed of this kind cannot tell, man himself seems to have been added to the inhabitants of the British land. In pursuit of game he sometimes ascended the valleys beyond the cavern, or even penetrated into its outer chambers; or perhaps there were even in those days rude and savage hill-men, inhabiting the forests and warring with the more cultivated denizens of plains below, which are now deep under the waters. Their weapons, lost in hunting, or buried in the flesh of wounded animals which crept to the streams to assuage their thirst, are those found in the cave earth. The absence of human bones may merely show that the mighty hunters of those days were too hardy, athletic, and intelligent, often to perish from accidental causes, and that they did not use this cavern for a place of burial. But the land again subsided. The valley of that now nameless river, of which the Rhine the themes, and the Severn may have alike been tributaries, disappeared under the sea; and some tribe, driven from the lower lands, took refuge in this cave, now again near the encroaching waves, and left there the remains of their last repasts ere they were driven farther inland or engulfed in the waters. For a time the cavern may have been wholly submerged, and the charcoal of the extinguished fires became covered with its thin coating of clay. But ere long it re-emerged to form part of an island, long barren and desolate; and the valleys having been cut deeper by the receding waters, it no longer received muddy deposits, and the crust formed by drippings from its roof contained only bones and pebbles washed by rains or occasional land floods from its own clay deposits. Finally, the modern forests overspread the land, and were tenanted by the modern animals. Man returned to use the cavern again as a place of refuge or habitation, and to leave there the relics contained in the black earth. This seems at present the only intelligible history of this curious cave and others resembling it; though, when we consider the imperfection of the results obtained even by a large amount of labour, and the difficult and confused character of the deposits in this and similar caves, too much value should not be attached to such histories, which may at any time be contradicted or modified by new facts or different explanations of those already known. The time involved depends very much, as already stated, on the question whether we regard the Post-glacial subsidence and re-elevation as somewhat sudden, or as occupying long ages at the slow rate at which some parts of our continents are now rising or sinking.[AT]

[AT] Another element in this is also the question raised by Dawkins, Geikie, and others as to subdivisions of the Post-glacial period and intermissions of the Glacial cold. After careful consideration of these views, however, I cannot consider them as of much importance.

Such are the glimpses, obscure though stimulating to the imagination, which geology can give of the circumstances attending the appearance of man in Western Europe. How far we are from being able to account for his origin, or to give its circumstances and relative dates for the whole world, the reader will readily understand. Still it is something to know that there is an intelligible meeting-place of the later geological ages and the age of man, and that it is one inviting to many and hopeful researches. It is curious also to find that the few monuments disinterred by geology, the antediluvian record of Holy Scripture, and the golden age of heathen tradition, seem alike to point to similar physical conditions, and to that simple state of the arts of life in which "gold and wampum and flint stones"[AU] constituted the chief material treasures of the earliest tribes of men. They also point to the immeasurable elevation, then as now, of man over his brute rivals for the dominion of the earth. To the naturalist this subject opens up most inviting yet most difficult paths of research, to be entered on with caution and reverence, rather then in the bold and dashing spirit of many modern attempts. The Christian, on his part, may feel satisfied that the scattered monumental relics of the caves and gravels will tell no story very different from that which he has long believed on other evidence, nor anything inconsistent with those views of man's heavenly origin and destiny which have been the most precious inheritance of the greatest and best minds of every age, from that early pre-historic period when men, "palaeolithic" men, no doubt, began to "invoke the name of Jehovah," the coming Saviour, down to those times when life and immortality are brought to light, for all who will see, by the Saviour already come.

[AU] So I read the "gold, bedolah, and shoham" of the description of Eden in Genesis ii.--the oldest literary record of the stone age.

In completing this series of pictures, I wish emphatically to insist on the imperfection of the sketches which I have been able to present, and which are less, in comparison with the grand march of the creative work, even as now imperfectly known to science, then the roughest pencilling of a child when compared with a finished picture. If they have any popular value, it will be in presenting such a broad general view of a great subject as may induce further study to fill up the details. If they have any scientific value, it will be in removing the minds of British students for a little from the too exclusive study of their own limited marginal area, which has been to them too much the "celestial empire" around which all other countries must be arranged, and in divesting the subject of the special colouring given to it by certain prominent cliques and parties.

Geology as a science is at present in a peculiar and somewhat exceptional state. Under the influence of a few men of commanding genius belonging to the generation now passing away, it has made so gigantic conquests that its armies have broken up into bands of specialists, little better then scientific banditti, liable to be beaten in detail, and prone to commit outrages on common sense and good taste, which bring their otherwise good cause into disrepute. The leaders of these bands are, many of them, good soldiers, but few of them fitted to be general officers, and none of them able to reunite our scattered detachments. We need larger minds, of broader culture and wider sympathies, to organise and rule the lands which we have subdued, and to lead on to further conquests.

In the present state of natural science in Britain, this evil is perhaps to be remedied only by providing a wider and deeper culture for our young men. Few of our present workers have enjoyed that thorough training in mental as well as physical science, which is necessary to enable men even of great powers to take large and lofty views of the scheme of nature. Hence we often find men who are fair workers in limited departments, reasoning most illogically, taking narrow and local views, elevating the exception into the rule, led away by baseless metaphysical subtleties, quarrelling with men who look at their specialties from a different point of view, and even striving and plotting for the advancement of their own hobbies. Such defects certainly mar much of the scientific work now being done. In the more advanced walks of scientific research, they are to some extent neutralised by that free discussion which true science always fosters; though even here they sometimes vexatiously arrest the progress of truth, or open floodgates of error which it may require much labour to close. But in public lectures and popular publications they run riot, and are stimulated by the mistaken opposition of narrow-minded good men, by the love of the new and sensational, and by the rivalry of men struggling for place and position. To launch a clever and startling fallacy which will float for a week and stir up a hard fight, seems almost as great a triumph as the discovery of an important fact or law; and the honest student is distracted with the multitude of doctrines, and hustled aside by the crowd of ambitious groundlings.

The only remedy in the case is a higher and more general scientific education; and yet I do not wonder that many good men object to this, simply because of the difficulty of finding honest and competent teachers, themselves well grounded in their subjects, and free from that too common insanity of specialists and half-educated men, which impels them to run amuck at everything that does not depend on their own methods of research. This is a difficulty which can be met in our time only by the general good sense and right feeling of the community taking a firm hold of the matter, and insisting on the organization and extension of the higher scientific education, as well as that of a more elementary character, under the management of able and sane men. Yet even if not so counteracted, present follies will pass away, and a new and better state of natural science will arise in the future, by its own internal development. Science cannot long successfully isolate itself from God. Its life lies in the fact that it is the exponent of the plans and works of the great Creative Will. It must, in spite of itself, serve His purposes, by dispelling blighting ignorance and superstition, by lighting the way to successive triumphs of human skill over the powers of nature, and by guarding men from the evils that flow from infringement of natural laws. And it cannot fail, as it approaches nearer to the boundaries of that which may be known by finite minds, to be humbled by the contemplation of the infinite, and to recognise therein that intelligence of which the human mind is but the image and shadow.

It may be that theologians also are needed who shall be fit to take the place of Moses to our generation, in teaching it again the very elements of natural theology; but let them not look upon science as a cold and godless demon, holding forth to the world a poisoned cup cunningly compounded of truth and falsehood; but rather as the natural ally and associate of the gospel of salvation. The matter is so put in one of those visions which close the canon of revelation, when the prophet sees a mighty angel having the "everlasting gospel to preach;" but he begins his proclamation by calling on men to "worship Him _that made heaven and earth and the sea and the fountains of waters_." Men must know God as the Creator even before they seek Him as a benefactor and redeemer. Thus religion must go hand in hand with all true and honest science. In this way only may we look forward to a time when a more exact and large-minded science shall be in perfect accord with a more pure and spiritual Christianity, when the natural and the spiritual shall be seen to be the necessary complements of each other, and when we shall hear no more of reconciliations between science and theology, because there will be no quarrels to reconcile. Already, even in the present chaos of scientific and religious opinion, indications can be seen by the observant, that the Divine Spirit of order is breathing on the mass, and will evolve from it new and beautiful worlds of mental and spiritual existence.