The arguments from geology in favor of a great antiquity for man may be summarized thus: (1) Human remains are found in caverns under very thick stalagmitic crusts, and in deposits of earth which must have acc.u.mulated before these stalagmites began to form, and when the caverns were differently situated with reference to the local drainages. (2) Remains of man are found under peat-bogs which have grown so little in modern times that their antiquity on the whole must be very great. (3) Implements, presumably made by men, are found in river-gravels so high above existing riverbeds that great physical changes must have occurred since they were acc.u.mulated. (4) One case is on record where a human bone is believed to have been found under a deposit of glacial age. (5) Human remains have been found under circ.u.mstances which indicate that very important changes of level have taken place since their acc.u.mulation. (6) Human remains have been found under circ.u.mstances which indicate great changes of climate as intervening between their date and that of the modern period. (7) Man is known to have existed, in Europe at least, at the same time with some quadrupeds formerly supposed to have been extinct before his introduction. (8) The implements, weapons, etc., found in the oldest of these repositories are different from those known to have been used in historic times.

These several heads include, I think, all the really material evidence of a geological character. It is evidence of a kind not easily reducible into definite dates, but there can be no doubt that its nature, and the rapid acc.u.mulation of facts within a small number of years, have created a deep and widespread conviction among geologists and archaeologists that we must relegate the origin of man to a much more remote antiquity than that sanctioned by history or by the Biblical chronology. I shall first review the character of this evidence, and then state a number of geological facts which bear in the other direction, and have been somewhat lost sight of in recent discussions. Of the facts above referred to, the most important are those which relate to caverns, peat-bogs, and river-gravels. We may, therefore, first consider the nature and amount of this evidence.

That the reader may more distinctly understand the geological history of these more recent periods of the earth's history which are supposed to have witnessed the advent of man, in Western Europe at least, I quote the following summary from Sir Charles Lyell of the more modern changes in that portion of the world. These are:

"First, a continental period, toward the close of which the forest of Cromer flourished; when the land was at least 500 feet above its present level, perhaps much higher. * * * The remains of _Hippopotamus major_ and _Rhinoceros etruscus_, found in beds of this period, seem to indicate a climate somewhat milder than that now prevailing in Great Britain. [This was a _Preglacial_ era, and may be regarded as belonging to the close of the Pliocene tertiary.]

"Secondly, a period of submergence, by which the land north of the Thames and Bristol Channel, and that of Ireland, was generally reduced to * * * an archipelago. * * * This was the period of great submergence and of floating ice, when the Scandinavian flora, which occupied the lower grounds during the first continental period, may have obtained exclusive possession of the only lands not covered with perpetual snow. [This represents the Glacial period; but according to the more extreme glacialists only a portion of that period.]

"Thirdly, a second continental period, when the bed of the glacial sea, with its marine sh.e.l.ls and erratic blocks, was laid dry, and when the quant.i.ty of land equalled that of the first period. * * * During this period there were glaciers in the higher mountains of Scotland and Wales, and the Welsh glaciers * * * pushed before them and cleared out the marine drift with which some valleys had been filled during the period of submergence. * * * During this last period the pa.s.sage of the Germanic flora into the British area took place, and the Scandinavian plants, together with northern insects, birds, and quadrupeds, retreated into the higher grounds. * * *

"Fourthly, the next and last change comprised the breaking up of the land of the British area once more into numerous islands, ending in the present geographical condition of things. There were probably many oscillations of level during this last conversion of continuous land into islands, and such movements in opposite directions would account for the occurrence of marine sh.e.l.ls at moderate heights above the level of the sea, notwithstanding a general lowering of the land. * * *

During this period a gradual amelioration of temperature took place, from the cold of the glacial period to the climate of historical times."[134]

The second continental period above referred to is that which appears on the best evidence to have been the time of the introduction of man; but such facts as that of the Settle Cave, and the implements of the breccia in Kent's Cave, if rightly interpreted, would make man preglacial or "interglacial."

The deposits found in caverns in France, Switzerland, Germany, Belgium, and England have afforded a large proportion of the remains from which we derive our notions of the most ancient prehistoric men of Europe. From the Belgian caves, as explored by M. Dupont, we learn that there were two successive prehistoric races, both rude or comparatively uncivilized. The first were men of Turanian type, but of great bodily stature and high cerebral organization, and showing remarkable skill in the manufacture of implements and ornaments of bone and ivory. These men are believed to have been contemporary with the earlier postglacial mammals, as the mammoth and hairy rhinoceros, and to have lived at a time when the European land was more extensive than at present, stretching far to the west of Ireland, and connecting Great Britain with the Continent. The skeletons found at Cro-Magnon, Mentone, and elsewhere in France fully confirm the deductions of Dupont as to this earliest race of Palaeocosmic, Palaeolithic, or antediluvian man. This grand race seems to have perished or been driven from Europe by the great depression of the level of the land which inaugurated the modern era, and which was probably accompanied by many oscillations of level as well as by considerable changes of climate. They were succeeded by a second race, equally Turanian in type, but of small stature, and resembling the modern Lapps. These were the "allophylian" peoples displaced by the historical Celts, and up to their time the reindeer seems to have existed abundantly in France and Germany. These two successive prehistoric populations have been termed respectively men of the "mammoth" age and men of the "reindeer" age. The Bible record would lead us to regard the earlier and gigantic men as antediluvian, and the smaller or Lappish race as postdiluvian. We may therefore, having already at some length considered the postdiluvian age, take up the mode of occurrence of the remains of the earlier of the two races--that of the mammoth age.

The caverns themselves may be divided into those of residence, of sepulture, and of driftage, though one cavern has often successively a.s.sumed two at least of these characters. In the caverns of residence large acc.u.mulations have been formed of ashes, charcoal, bones, and other debris of cookery, among which are found flint and bone implements, the general character of which, as well as that of the needles, stone hammers, mortars for paint, and other domestic appliances, are not more dissimilar from those of the Red Indian and Esquimau races in North America than these are from one another, and in many things, as in the bone harpoons, the resemblance is very striking indeed. In tendency to imitative art, and in the skill of their delineations of animals, the prehistoric men seem to have surpa.s.sed all the American races except the semi-civilized mound-builders and the more cultivated Mexican and Peruvian nations.

With regard to the residence of these men of the mammoth age in caverns, several things are indicated by American a.n.a.logies to which some attention should be paid.

It is not likely that caverns were the usual places of residence of the whole population. They may have been winter houses for small tribes and detached families of fugitives or outlaws, or they may have been places of resort for hunting parties at certain seasons of the year. The large quant.i.ties of broken and uncooked bones of particular species, as of the horse and reindeer, in some of the caverns, would farther indicate a habit of making great battues, like those of the American hunting tribes, at certain seasons, and of preparing quant.i.ties of pemmican or dried meat preserved with marrow and fat for future use. The number of bone needles found in some of the caves would seem to hint that, like the Americans, they sewed up their pemmican in skin bags. The mult.i.tude of flint flakes and of rude stone implements applicable to breaking bones certainly indicates a wholesale cutting of flesh and preparation of marrow. In the "Story of the Earth," I have suggested in connection with this that there may have been towns or villages of these people unknown to us, and which would afford higher conceptions of their progress in the arts. This antic.i.p.ation appears recently to have been realized in the discovery of such a town or fortified village of the mammoth age at Soloutre, in France, and which seems to afford evidence that these ancient people had already domesticated the horse, using it as food as well as a beast of burden, in the manner of the Khirgis and certain other Tartar tribes of Central Asia.[135] This, with the undoubtedly high cerebral organization indicated by the skulls of the mammoth age, notably raises our estimate of the position of man at this early date.

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 debris, 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 Palaeocosmic 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 coa.r.s.ely marked features, of large stature and muscular vigor, surpa.s.sing 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 cla.s.sed some of those near Liege, 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 ma.s.s 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 ma.s.s, 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 quant.i.ty 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 ma.s.s, 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 a.s.signing any reason, that none of these bones could, like the ma.s.ses 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 acc.u.mulation, 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 a.s.suage 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 Palaeocosmic men of the mammoth age.

What is the absolute antiquity of the Palaeocosmic age in Europe? We have no monumental or historical chronology to answer this question, but only the measures of time furnished by the acc.u.mulation of deposits, by the deposition of stalagmite, by the gradual extinction of animals, and by the erosion of valleys and other physical changes.

These somewhat loose measures have been applied in various ways, but the tendency of geologists, from the prevalence of uniformitarian views, and the prejudice created by familiarity with the long times of previous geologic periods, has been to a.s.sign to them too great rather than too little value, both as measures of time and as indicating a remote antiquity.

With reference to the acc.u.mulation of deposits, whether derived from disintegration of the roof and walls of the cave, introduced by land floods or river inundations or by the residence of man, their rate is of very difficult estimation. Loose stones fallen from the roof, as in the case of Kent's Cave, would give a fair measure of time if we could be sure that the climate had continued uniform, and that there had been no violent earthquakes. Mr. Pengelly has, however, hopelessly given up this kind of evidence. Where, as in the case of many of these caves, land floods and river inundations have entered, these may have been frequent or separated by long intervals of time, and they may have been of great or small amount. Where, for instance, as in one of the Belgian caves, there are six beds of ossiferous mud, but for the fact that five layers of stalagmite separate them we might not have known whether they represent six annual inundations, or floods separated by many centuries from each other.

In the case of the Victoria Cave at Settle, Dawkins, reasoning from the acc.u.mulation of two feet of detritus over British remains that may be supposed to be 1200 years old, gives a basis which would at the same rate of deposit allow about 5000 years for the date of palaeolithic men; but Prestwich and others, on the basis of stalagmite deposits, claim a vastly higher antiquity for the men who made the implements found in Kent's Hole and Brixham.

If we now turn to these stalagmite floors, when we consider that they have been formed by the slow solution of limestone by rain-water charged with carbonic acid, and the dropping of this water on the floor, and when we are told that in Kent's Cavern a marked date shows that the stalagmite has grown at the rate of only one twentieth of an inch since 1688, and that there are two beds of stalagmite, one of which is in some places twelve feet thick, we are impressed with the conviction of a vast antiquity. But when we are told by Dawkins that the rate of deposit in Ingleborough Cave may be estimated at a quarter of an inch per annum, and when we consider that the present rate of deposit in Kent's Hole is probably very different from what it was in the former condition of the country, stalagmite becomes a very unsafe measure of time. With respect again to the acc.u.mulation of kitchen-midden stuff in the course of the occupancy of caverns, this proceeds with great rapidity, when caves are steadily occupied and it is not the practice to cleanse out the debris of fires, food, and bedding. Even when the occupation is temporary, a tribe of savages engaged with the preparation of dried meat and pemmican in a very short time produce a considerable heap of bones and other rejectamenta.

Looking next to the extinction of animals, we find that the species found in the oldest deposits containing human remains are in part still extant. Others which are locally extinct we know existed in Europe until historical times, that is, within the last two thousand years. How long previously to this the others became extinct we have no certain means of knowing, though it seems probable that they disappeared gradually and successively. We have, however, farther to bear in mind the possibility of cataclysms or climatal changes which may have proved speedily fatal to many species over large areas. In any case we have this certain fact that, though the time elapsed has been sufficient for the extinction of many species, it does not seem to have sufficed to effect any noteworthy change on those that survived. Farther, we may consider that time is only one factor in this matter, and not the one which is the efficient cause of change, since we know no reason why one species of animal should not continue to be reproduced as long as another, but for the occurrence of physical changes of a prejudicial character.

We have still remaining the changes which have taken place in the erosion of valleys since the caverns were occupied. Dupont informs us that the openings of some of the caverns once flooded by rivers are now in limestone cliffs two hundred feet above the water, while no appreciable lowering of the bottoms of the ravines is taking place now. This would in some contingencies put back the period of filling of the caves to an indefinite antiquity. But then the questions occur--Was there once more water in the rivers or more obstruction at their outlets, or was the erosive power greater at one time than now, or were the river valleys excavated in still more ancient time, and partly filled with mud when the water entered the caves, and may this mud have been since swept away? So, in like manner, the waters flowing in the channels near Brixham Cave and Kent's Hole were apparently about seventy feet higher in times of flood than at present, but the time involved is subject to the same doubts as in the case of the Belgian caves. Hughes has well remarked that elevations of the land, by causing rivers to form waterfalls and cascades, which they cut back, may greatly accelerate the rate of erosion. Farther, there is the best reason to believe that in the glacial period many old valleys were filled with clay, and that the modern cutting consisted merely in the removal of this clay. Belt has shown in a recent paper[139] good reason to believe that this is the case with the Falls of Niagara, and that the cutting actually effected through rock within the later Pleistocene and modern period has been that only of the new gorge from the whirlpool to Queenstown, the main part of the ravine being of older date and merely re-excavated. This would greatly reduce the ordinary estimate of time based on the cutting of the Niagara gorge.

This leads us next to consider the occurrence of human remains and objects of art in the river-gravels themselves, and the amount of excavation and deposit involved in the deposition of these gravels.

In the river-gravels of the Somme, and of many other rivers in France and Southern England, chipped flints and rude flint implements are found in so great quant.i.ty as to imply that the beds and banks of these streams were resorted to for flint material, and that the unfinished and rejected implements left in the holes and trenches, or on the heaps where the work was carried on, were afterward sorted by running water, perhaps in abnormal floods and debacles, such as occur in all river valleys occasionally, perhaps in that great diluvial catastrophe which seems to have terminated the residence of Palaeocosmic man in Europe. Wilson has well shown how the heaps left by American tribes in and near their flint quarries would furnish the material for such acc.u.mulations. The time required for the erosion of the valleys and the deposit of the gravels has been very variously estimated. In the case of the Somme, which river is not appreciably deepening its bed, if we suppose it to have cut its wide valley to the depth of one hundred and fifty feet out of solid chalk since the so-called "high level" gravels of France and the South of England were deposited, the time required shades off into infinity. So Evans, in his work on "The Ancient Stone Implements of Great Britain," looking upon the amount of excavation of wide and deep valleys since the stone implements of Bournemouth are supposed to have been deposited in gravel, says, "Who can fully comprehend how immensely remote was the epoch when that vast bay was high and dry land?" and he becomes poetical in delineating the view that must have met the eyes of "palaeolithic" man. And undoubtedly, if one is to be limited to the precise nature and amount of causes now at work in the district, the time must not only be "immensely remote," but illimitably so. The difficulty lies with the exaggerated uniformitarianism of the supposition that such causes could have produced the results. But, for reasons to be immediately stated, the time required is liable to numerous deductions; and recently Tylor, Pattison, Collard, and others have insisted ably on these deductions, as has also Professor Hughes, of Cambridge. I have myself urged them strongly in the work already referred to.

In the first place, when we see a deep river valley in which the present stream is doing an almost infinitesimal amount of deepening, we are not to infer that this represents all its work past and present. In times of unusual flood it may do in one week more than in many previous years. Farther, if there have been elevations or depressions of the land, when the land has been raised the cutting power has at once been enormously increased, and when depressed it has been diminished, or filling has taken the place of cutting. Again, if the climate in time past has been more extreme, or the amount of rainfall greater, the cutting action has then been proportionally rapid. Perhaps no influence is greater in this respect than that which is known to the colonists in Northeastern America as "ice-freshets,"

when in spring, before the ice has had time to disappear from the rivers, sudden thaws and rains produce great floods, which rushing down over the icy crust, or breaking and hurling its ma.s.ses before them, work terrible havoc on the banks and alluvial flats, depositing great beds of gravel, and sweeping away immense ma.s.ses that had lain undisturbed for centuries. Now we know that in Europe the human period was preceded by what has been termed the glacial age, and as it was pa.s.sing away there must have been unexampled floods and ice-freshets, and a temporary "pluvial period," as it has been called, in which the volume of the rivers was immensely increased. Farther, it is an established fact that the period of the appearance of man was a time when the continents in the northern hemisphere were more elevated than at present, and when consequently the cutting action of rivers was at a maximum. This was again followed by a period of depression, accompanied probably by many local cataclysms, if not by a general deluge; and there are strong geological reasons to believe that this convulsion was connected with the disappearance from Europe of Palaeocosmic man, and many of the animals his contemporaries. This view I advocated some time ago in my "Story of the Earth;" and more recently Mr. Pattison, in an able paper read before the Victoria Inst.i.tute, has developed it in greater detail, and supported it by a great ma.s.s of geological authority. If the Palaeocosmic period was one of continental elevation, when the greater seats of population were in the valleys of great rivers now covered by the German Ocean and the English Channel, and when the valleys of the Thames and the Somme were those of upland streams frequented by straggling parties and small tribes, and the seats of extensive flint factories for the supply of the plains below, and if this state of things was terminated by a diluvial debacle, we can account for all the phenomena of the drift implements without any extravagant estimate of time.

I quote with much pleasure on this subject the following from the report of a lecture on "Geological Measures of Time," by Professor Hughes, before the Royal Inst.i.tution of London. Hughes was, like myself, a companion of Sir Charles Lyell in some of his journeys, though belonging to a younger generation of geologists, and is an accurate observer and reasoner.

"Another method of estimating the lapse of time is founded upon the supposed rate at which rivers scoop out their channels. Although no very exact estimates have been attempted, still the immense quant.i.ty of work that has been done, as compared with the slow rate at which a river is now excavating that same part of the valley, is often appealed to as a proof of a great lapse of time.

"The fact of such an enormous lapse of time is not questioned, but this part of the evidence is challenged.

"The previous considerations of the rate of acc.u.mulation of silt on the low lands prepares us to inquire whether there is any waste at all along the alluvial plains. Several examples were given to show that the lowering of valleys was brought about by receding rapids and waterfalls; for instance, following up the Rhine, its terraces could often be traced back to where the waterfall was seen to produce at once almost all the difference of level between the river reaches above and below it. At Schaffhausen the river terrace below the hotel could be traced back and found to be continuous with the river margin above the fall. The wide plains occurring here and there, such as the Mayence basin, were due to the river being arrested by the hard rocks of the gorges below Bingen so long that it had time to wind from side to side through the soft rocks above the gorges. When waterfalls cut back to such basins or to lakes they would recede rapidly, tapping the waters of the lake, eating back the soft beds of the alluvial plains, and probably in both cases leaving terraces as evidence, not of upheavals or of convulsions, but of the arrival of a waterfall which had been gradually travelling up the valley. So when the Rhone cuts back from the falls at Belgarde we shall have terraces where now is the sh.o.r.e of Geneva; so also when the Falls of Schaffhausen, and ages afterward when the Falls of Laufenburg have tapped the Lake of Constance, there will be terraces marking its previous levels. And so we may explain the former greater extent of the Lake of Zurich, which stood higher and spread wider by Utznach and Wetzikon before it was tapped by the arrival of waterfalls, which cut back into it and let its waters run off until they fell to their present level.

"A small upheaval near the mouth of a river would have a similar effect. The Thames below London and the Somme below St. Acheul can now only just hand on the mud brought down from higher ground; but suppose an elevation of a hundred feet over those parts of England and France (quite imperceptible if extended over 10,000, 1000, or even 100 years), and the rivers would tumble over soft mud and clay and chalk, and soon eat their way back from Sheppey to London, and from St.

Valery to Amiens.

"So when we want to estimate the age of the gravels on the top of the cliff at the Reculvers, or on the edge of the plateau of St. Acheul, we have to ask, not how long would it take the rivers to cut down to their present level from the height of those gravels at the rate at which that part of their channel is being lowered now, but how long would it take the Somme or Thames, which once ran at the level of those gravels, to cut back from where its mouth or next waterfall was then to where it runs over rapids now. We ought to know what movements of upheaval and depression there have been; what long alluvial flats or lakes which may have checked floods, but also arrested the rock-protecting gravel; how much the wash of the estuarine waves has helped. In fact, it is clear that observations made on the action of the rivers at those points now have nothing to do with the calculation of the age of the terraces above, and that the circ.u.mstances upon which the rate of recession of the waterfalls and rapids depends are so numerous and changeable that it is at present unsafe to attempt any estimate of the time required to produce the results observed."

I may close this discussion by quoting from the paper of my friend Mr.

Pattison, already referred to, the following summing up of his conclusions, in which I fully concur:

"We may a.s.sume it as established that there was a time when England was connected with the Continent, when big animals roamed in summer up the watercourses and across the uplands, and man, armed only with rude stones, followed them into the marshes and woods, hunted them for sustenance, and consumed them in shelter of caves, then accessible from the river levels. This state of things was continued until disturbed by oscillations of surface, accompanied by excessive rainfalls and rushes of water from the water-sheds of the rivers, until the great animals were driven out or destroyed, and man ceased to visit these parts. The disturbances continued, the Strait of Dover was formed, the configuration of the soft parts of the islands and continents was fixed, action subsided, and the present state of things obtained. Man resumed his residence, but with loss of the mammoth and its companions. The reindeer now const.i.tuted the type of a state of things which lasted down to the historic period, without any other from that time to this. * * *

"Chronologists are agreed that about 2000 years B.C. Abraham migrated from Mesopotamia to Canaan, and that at this time Egypt at least was old in civilization. Beyond this we have no positive scale of time in Scripture; for it is evident, from the narrative itself, that the latter does not cover the whole time. * * *

"Ussher estimates from Scripture the creation of man as about 2000 years before this. During the latter portion of this time civilization was proceeding under settled governments in the East, interrupted, says the record and tradition, by a flood. * * *

"So Lucretius:

'Thus, too, the insurgent waters once o'erpowered, As fables tell, and deluged many a state; Till, in its turn, the congregated waves By cause more potent conquered, heaven restrain'd Its ceaseless torrents, and the flood decreased.'

Barbarism covered the whole Western world; neither in the 2000 years before Abraham, nor in the 2000 years afterward, have we any light reflected from these regions to the East.

In this 4000 years, or in the somewhat longer period which probably will be ultimately settled as warranted by the record, we place hypothetically all the phenomena of the later mammalian age, including the introduction of man as a hunter, the first occupation of the caves by him also, the diluvial phenomena of the wide valleys, the oscillations and disturbances of the earth's crust, alterations in the coast-line, and physical settlement of the country; after this comes the second occupation of the caves. In short, if we say that, hypothetically, the whole first known human age occurred within 4000 years of the Christian era, no one can say that it is geologically impossible. Who can say that 1643 years is insufficient to comprise all the phenomena that occurred during a period confessedly characterized by more rapid and extensive action than at present--a period during which ruptures in the earth's crust, oscillations, and permanent uprising took place, and the intermittent action of violent floods caused the deposit and disturbance and resettlement of the gravels and brick-earth? There is nothing to interfere with the prevalent opinion that man was introduced here while the glacial period was dying out, and while it was still furnishing flood-waters sufficient to scour and re-sort the gravels of the valleys down which they flowed. This supposition may be extended to both the great continents."

To conclude: Our mode of reconciling the Mosaic history of antediluvian man with the disclosures of the gravels and caves would be to identify Palaeocosmic man, or man of the mammoth age, with antediluvian man; to suppose that the changes which closed his existence in Europe as well as Western Asia were those recorded in the Noachian deluge; and that the second colonization of the diminished and shrunken Europe of the modern period was effected by the descendants of Noah. It may be asked--Must we suppose that the Adam of the Bible was of the type of the coa.r.s.ely featured and gigantic men of the European caverns? I would answer--Not precisely so; but it is quite possible that Adam may have been Turanian in feature. We should certainly suppose him to have been a man well developed in brain and muscle. Such men as those found in the caves would rather represent the ruder "Nephelim," the "giants that were in those days," than Adam in Eden. Farther, the new colonists of Europe after the deluge would no doubt be a very rude and somewhat degenerate branch of Noachidae, probably driven before more powerful tribes in the course of the dispersion. The higher races of both periods are probably to be looked for in Western Asia; but even there we must expect to find cave men like those whose remains were found by Tristram in the caves near Tyre, and like the Horim of Moses; and we must also expect to find the antediluvian age in the main an age of stone everywhere, and its arts, except in certain great centres of population, perhaps not more advanced than those of the Polynesians, or those of the agricultural American tribes before the discovery of America by Columbus.

As a geologist, and as one who has been in the main of the school of Lyell, and after having observed with much care the deposits of the more modern periods on both sides of the Atlantic, I have from the first dissented from those of my scientific brethren who have unhesitatingly given their adhesion to the long periods claimed for human history, and have maintained that their hasty conclusions on this subject must bring geological reasoning into disrepute, and react injuriously on our n.o.ble science. We require to make great demands on time for the prehuman periods of the earth's history, but not more than sacred history is willing to allow for the modern or human age.