With regard to caves of sepulture, the same remark may be made as with regard to the caves of residence. They do not seem to have been the burial-places of large populations, but only occasional places of interment, few bodies being found in them, and these often interred in the midst of culinary débris, evidencing previous or contemporary residence. With regard to the latter, it seems to have been no uncommon practice with some North American tribes to bury the dead either in the floors of their huts or in their immediate proximity. It is probable, however, that the few examples known of caves of sepulture of this period indicate not tribal or national places of burial, but occasional and accidental cases, happening to hunting or war parties, perhaps remote from their ordinary places of residence. In so far as method of burial is concerned, the men of the Palæocosmic or Mammoth age seem to have buried the dead extended at full length, and not in the crouching posture usual with some later races. Like the Americans, they painted the dead man, and buried him with his robes and ornaments, and probably with his weapons, thus intimating their belief in happy hunting-grounds beyond the grave. [136] I may remark here that all the known interments of the mammoth age indicate a race of men of great cerebral capacity, with long heads and coarsely marked features, of large stature and muscular vigor, surpassing indeed much in all these respects the average man of modern Europe. These characteristics befit men who had to contend with the mammoth and his contemporaries, and to subdue the then vast wildernesses of the eastern continent, and they correspond with the Biblical characteristics of antediluvian man.
Among caves of driftage may be classed some of those near Liège, in Belgium, and, partially at least, those of Kent's Hole and Brixham, in England. In these only disarticulated remnants of human skeletons, or more frequently only flint implements, some of them of doubtful character, have been found. In my "Story of the Earth," I have taken the carefully explored Kent's Cavern of Torquay as a typical example, and have condensed its phenomena as described by Mr. Pengelly. I now repeat this description, with some important emendations suggested by that gentleman in more recent reports and in private correspondence.
The somewhat extensive and ramifying cavern of Kent's Hole is an irregular excavation, evidently due partly to fissures or joints 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, of the deposits as yet known, is a "breccia," or mass of broken and rounded stones, with hardened red clay filling the interstices. Some of the stones are of the rock which forms the roof and walls of the cave, but the greater number, especially the rounded ones, are from more distant parts of the surrounding country. Many are fragments of grit from the Devonian beds of adjacent hills. There are also fragments of stalagmite from an old crust broken up when the breccia was deposited, and possibly belonging to Pliocene times. In this mass, the depth of which is unknown, are numerous bones, nearly all of one kind of animal, the cave bear or bears, for there may be more than one species—creatures which seem to have lived in Western Europe from the close of the Pliocene down to the modern period. They must have been among the earliest and most permanent tenants of Kent's Hole at a time when its lower chambers were still filled with water. Teeth of a lion and of the common fox also occur in this deposit, but rarely. 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 more than twelve 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 the occurrence of chipped flints supposed to be artificial; but which, in so far as I can judge from the specimens described and figured, must still be regarded as of doubtful origin.
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 besides fragments of charcoal scattered in the mass, there is in one spot, near the top, a limited layer of burned 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 perhaps some of the bones and implements, and breaking up in places the old stalagmite floor. [137] 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 neighboring valleys of nearly one hundred feet above its present height. The cave earth is covered by a second crust of stalagmite, less dense and thick than that below, and containing only a few bones, which are of the same general character with those beneath, 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; and Mr. Pengelly appears to affirm, though without assigning any reason, that none of these bones could, like the masses of stalagmite, have been lifted from lower beds, or washed into the cave from without.
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, all of them modern, and contains works of art from the old British times before the Roman invasion up to the porter bottles and dropped half-pence 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 neighboring 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 than any other postglacial monuments, shown the existence 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 seem to have been applied, namely, the rate of growth of stalagmite and the rate of erosion of neighboring valleys, are, from the very sequence of the deposits, obviously worthless; and the only apparently constant measure, namely, the fall of blocks from the roof, seems not to have been applied, and Mr. Pengelly declares that it can not be practically used. We are therefore quite uncertain as to the number of centuries involved in the filling of this cave, and must remain so until some surer system of calculation can be devised. We may, however, attempt to sketch the series of events which it indicates.
The animals found in Kent's Hole are all "postglacial," some of them of course survivors from "preglacial" times, and some of them still surviving. They therefore inhabited the country after it rose from the great glacial submergence. Perhaps the first colonists of the coast of Devonshire in this period were the cave bears, migrating on floating ice, and subsisting like the arctic bear and the black bear of Anti-costi, on fish, and on the garbage cast up by the sea. They may have 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. In the case of such a deposit as this breccia, however, the precise time when its materials were finally laid down in their present form, or the length of time necessary for its accumulation, can not be definitely settled. It may be a result of continued torrential action or of some sudden cataclysm. 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 streams, their beds not yet emptied of glacial detritus, washed into it stones and mud, and probably bones also, while it appears that hyenas occupied the cave at intervals, and dragged in remains of mammals 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 an unstratified and therefore probably often-disturbed bed of this kind can not 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, and other implements dropped in the cavern or 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 the 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. The fragments of charcoal show that they were acquainted with fire, and possibly that they sometimes took shelter in the cave. But the land again subsided. The valley of that now nameless river, of which the Rhine and the Thames may have alike been tributaries, disappeared under the sea; and perhaps some tribe, driven from the lower lands, took up its abode 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 and 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 labor, 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 on the answer to the question whether we should regard the postglacial 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.
Mr. Pengelly thinks it possible, but not proved, that the lower breccia of Kent's Cavern may be interglacial or preglacial in age. One case only is known where a human bone has been found in a cavern under deposits supposed to be of the nature of the glacial drift. It is that of the Victoria Cave, at Settle, in Yorkshire. At this place a human fibula was found under a layer of boulder clay. But there are too many chances of this bone having come into this position by some purely local accident to allow us to attach much importance to it until future discoveries shall have supplied other instances of the kind. [138]
I may close this survey of the cave deposits with a summary of the results of M. Dupont, as obtained from two of the caves explored by him, that of Margite and that of Frontal. In the first of these caverns, resting on rolled pebbles which covered the floor, were four distinct layers of river mud deposited by inundations, and amounting to two yards and a half in thickness. In all of these layers were bones. The lowest contained rude flint implements, and bones of the mammoth, rhinoceros, bear, horse, chamois, reindeer, stag, and hyena. In the overlying deposits are some flint implements of more artistic form and a greater prevalence of the bones of the reindeer. In the second cave, that of Frontal, over a similar deposit of alluvial mud of the mammoth age, was found a sepulchre containing the remains of sixteen individuals, of the second or diminutive Lappish race before referred to. The door of the cave had been closed by these people with a slab of stone, and in front was a hearth for funeral feasts, built on the deposits of the mammoth age, and containing bones of animals all recent or now living in Belgium, and without any traces of the bones of the extinct quadrupeds. This burial-place belonged to the Neocosmic yet prehistoric race which replaced the Palæocosmic men of the mammoth age.