Natural History Review/1862/On the Evidence of the Antiquity of Man, afforded by the Physical Structure of the Somme Valley

XXVI.—On the Evidence of the Antiquity of Man, afforded by the Physical Structure of the Somme Valley. By John Lubbock, Esq., F.R.S.

While we have been straining our eyes to the East, and eagerly watching excavations in Egypt and Assyria, suddenly a new light has arisen in the midst of us; and the oldest relics of man yet discovered, have occurred, not among the ruins of Nineveh or Heliopolis, not in the sandy plains of the Nile or the Euphrates, but in the pleasant valleys of England and France, along the banks of the Seine and the Somme, the Thames and the Waveney.

So unexpected were these discoveries, so irreconcileable with even the greatest antiquity then assigned to the human race, that they were long regarded with neglect and suspicion. M. Boucher de Perthes to whom we are primarily indebted for this great step in the history of mankind, published his first work on the subject, "De l'industrie primitive, ou les arts et leur origine," in the year 1846. In this he announced that he had found human implements in beds ummistakeably belonging to the age of the drift. In his "Antiquités Celtiques et Antédiluviennes" (1847), he also gave numerous illustrations of these stone weapons, but unfortunately the figures were so small and rude, as scarcely to do justice to the originals. For seven years M. Boucher de Perthes made few converts; he was looked upon as an enthusiast, almost as a madman. At length, in 1853, Dr. Rigollot, till then sceptical, examined for himself the drift at the now celebrated St. Acheul, found several weapons, and believed. Still the new creed met with but little favour; prophets are proverbially with- out honour in their own country, and M. Boucher de Perthes was no exception to the rule. At last, however, the tide turned in his favour. Dr. Falconer, passing through Abbeville, visited his collection, and made known the result of his visit to Mr. Joseph Prestwich, who, accompanied by Mr. John Evans, immediately proceeded to Abbeville and examined carefully not only the flint weapons, but also the beds in which they were found. For such an investigation our two countrymen were especially qualified: Mr. Prestwich from his long examination and great knowledge of the more recent strata; and Mr. Evans as having devoted much study to the stone implements belonging to what we must now consider as the second, or at least the more recent, stone-period. On their return to England Mr. Prestwich communicated the results of his visit to the Royal Society,[1] (On the Occurrence of Flint Implements associated with the remams of extinct species, in beds of a late Geological Period, May 19, 1859), while Mr. Evans described the implements themselves in the Transactions of the Society of Antiquaries (1860).

Shortly afterwards Mr. Prestwich returned to Amiens and Abbeville, accompanied by Messrs. Godwin Austen, J. W. Flower, and R. W. Mylne. In the same year Sir Charles Lyell, whose opinion on the subject was naturally expected with great interest, visited the now celebrated localities. In 1860, I made my first visit with Mr. Busk and Captain Galton, under the guidance of Mr. Prestwich, while Sir Roderick Murchison, Professors Henslow, Ramsay, Rogers, Messrs. H. Christy, Rupert Jones, James Wyatt, and other geologists, followed on the same errand. M. L'Abbé Cochet, therefore, in his "Rapport adressé a Monsieur le Sénateur Préfet de la Seine-Inférieure," (1860) does no more than justice to our countrymen, when after a well-merited tribute of praise to M. Boucher de Perthes, and Dr. Rigollot, he adds, "Mais ce sont les Géologues Anglais, en tète desquels il faut placer d'abord M.M. Prestwich et Evans, puis M. M. Flower, Mylne, et Godwin Austen, et enfin Sir C. Lyell . . . . qui . . . . ont fini par élever à la dignité de fait scientifique la découverte de M. Boucher de Perthes."

Soon after his return, Mr. Prestwich addressed a communication to the Academy of Sciences through M. Elie de Beaumont, in which he urged the importance of these discoveries, and expressed a hope that they would stimulate "les géologues de tous les pays à une étude encore plus approfondie des terrains quaternaires." The subject being thus brought prominently before the geologists of Paris, M. Gaudry, well known for his interesting researches in Greece, was sent to examine the weapons themselves, and the localities in which they were found.

M. Gaudry was so fortunate as to find several flint weapons in situ, and hi» report, which entirely confirmed the statements made by M. Boucher de Perthes, led others to visit the valley of the Somme, among whom I may mention M.M. de Quatrefages, Lartet, Collomb, Hebert, de Verneuil, and G. Pouchet.

In the "Antiquités Celtiques," M. Boucher de Perthes suggested some gravel pits near Grenelle at Paris, as being, from their position and appearance, likely places to contain flint implements. M. Gosse of Geneva has actually found flint implements in these pits, being, I believe, the first discovery of this nature in the valley of the Seine.[2] In that of the Oise a small hatchet haa been found by M. Peigné Delacourt at Précy, near Creil.

Dr. Noulet has also found flint weapons with remains of extinct animals at Clermont, near Toulouse.

Nor have these discoveries been confined to France. There has long been in the British Museum a rude stone weapon, described as follows:—"No. 246. A British weapon, found with elephant's tooth, opposite to black Mary's, near Graves inn lane. Conyers. It is a large black flint, shaped into the figure of a spear's point." Mr. Evans tells us, moreover, (l. c. p. 22) "that a rude engraving of it illustrates a letter on the Antiquities of London, by Mr. Bagford, dated 1715, printed in Hearne's edition of Leland's Collectanea, Vol. I. 6. p. lxii. From his account it seems to have been found with a skeleton of an elephant in the presence of Mr. Conyers." This most interesting weapon agrees exactly with those found in the valley of the Somme.

In the museum belonging to the Society of Antiquaries, Mr. Evans found, on his return from Abbeville, some specimens exactly like those in the collection of M. Boucher de Perthes. On examination it proved that they had been presented by Mr. Frere, who found them with bones of extinct animals in a gravel pit at Hoxne in Suffolk, and had well described and figured them in the Archæologia for the year 1800.

Again, twenty-five years ago, Mr. Whitburn of Godalming, (See Prestwich, Geol. Jour. August 1861), examining the gravel pits between Guildford and Godalming, remarked a peculiar flint, wnich he carried away and has since preserved in his collection. It belongs to the "drift" type, but is very rude. Thus this peculiar type of flint implement has been actually found in association with the bones of the mammoth on various occasions during nearly a hundred and fifty years! While, however, these instances remarkably corroborate the statements made by M. Boucher de Perthes, they in no way detract from the credit due to that gentleman.

In addition to the above mentioned, similar hatchets have been found in Suffolk, Kent, Bedfordshire, and Hertfordshire. In the first of these counties Mr. Warren of Ixworth obtained one from a workman in a gravel pit near Icklingham, and he subsequently found another himself. This specimen closely resembles the one figured in this Review (Vol. I. Pl. VII. fig. 10), which was given to me by M. Marcotte of Abbeville, who obtained it from Moulin Quignon.

The next discovery was made by Mr. Leech, on the shore between Herne Bay and Reculvers, whence altogether eleven specimens have been obtained, six found by Mr. Leech, and five subsequently by Messrs. Evans and Prestwich and Wyatt.[3] In the gravel near bedford, again associated with remains of the mammoth, rhinoceros, hippopotamus (?), ox, horse, and deer, Mr. Wyatt has found implements resembling both of the two principal types found at Abbeville and Amiens.

Finally, Mr. Evans himself, near Abbots Langley in Hertfordshire, has picked up on the surface of a field a weathered hatchet with the top broken off, but otherwise identical in form with the spear-head-shaped specimens from Amiens and Herne Bay.

But why, it mav be asked, should the history of this question be so recounted? why should it be treated differently from any other scientific discovery? The answer is not difficult. That the statement by Mr. Frere has been forgotten for half a century; that the weapon found by Mr. Conyers should have lain unnoticed for more than double that time; that the discoveries by M. Boucher de Perthes have been ignored for fifteen years; that the numerous cases in which caves have contained the remains of men together with those of extinct animals, have been explained away; are facts which show how deeply rooted was the conviction that man belonged altogether to a more recent order of things, and, whatever other accusation may be brought against them, geologists can at least not be said to have hastily accepted the theory of the coexistence of the human race with the now extinct Pachydermata of Northern Europe.

Though, however, the distinguished geologists to whom I have referred, have all, with one exception, expressed themselves more or less strongly as to the great antiquity ot these curious weapons, still, I do not wish that they should be received as judges; I only claim the right to summon them as witnesses.

The questions to be decided may be stated as follows:—

1st. Are the so-called flint implements of human workmanship, or the results of physical agencies?

2ndly. Are the flint implements of the same age as the bones of the extinct animals with which they occur?

3rdly. Are we entitled to impute a high antiquity to the beds in which these remains occur?

4thly. What are the conditions under which they were deposited?

To the first three of these questions an affirmative answer would be given, almost unanimously, by those geologists who have given any special attention to the subject. Fortunately, however, there is one exception to this rule; Blackwood's Magazine for October, 1860, contains an article in which the last two questions are maintained to be still unanswered, and in which therefore a verdict of "Not Proven" is demanded. Not indeed that there is any difference of opinion as to the weapons themselves. "For more than twenty years," says Prof. Ramsay, "I have daily handled stones, whether fashioned by nature or art, and the flint hatchets of Amiens and Abbeville seem to me as clearly works of art as any Sheffield whittle."[4] It will be better however to quote from the candid sceptic in Blackwood. "They bear," he admits (p. 438), "unmistakeably the indications of having been shaped by the skill of man." But best of all, an hour or two spent in a pit, examining the forms of ordinary flint gravel would, we are sure, convince any man that these stones, rude though they be, are undeniably fashioned by the hand of man.

Still, it might be supposed that they were forgeries, made by the workmen to entrap unwary geologists. They have however been found by Messrs. Boucher de Perthes, Henslow, Christy, Plower, Gaudry, Pouchet, Wyatt, and others. One seen, though not found in situ is thus described by Mr. Prestwich. "It was lying flat in the gravel at a depth of 17 feet from the original surface, and 61/2 from the chalk. One side slightly projected. The gravel around was undisturbed, and presented its usual perpendicular face. I carefully examined the specimen, and saw no reason to doubt that it was in its natural position, for the gravel is generally so loose, that a blow with a pick disturbs and brings it down for some way around; and the matrix is too little adhesive to admit of its being built up again as before with the same materials. . . . . I found also afterwards, on taking out the flint, that it was the thinnest side which projected, the other side being less finished and much thicker."[5] Neither in my first visit, nor this spring, when with Mr. Prestwich and Mr. Evans, I made another careful examination of these localities, was I so fortunate as find any implement in situ. But evidence of this nature, though interesting, is unnecessary; the flints speak for themselves. Originally of a dull black, they have been more or less discolored and their surfaces are generally stained yellow or white, according to the nature of the beds in which they have been lying. As this discoloration follows the contours of the present surfaces, it is evident that the alteration of color has been subsequent to the manufacture, as I have attempted to show in the first Volume of this Review. (Pl. VII. fig. 11.) Even when, as is the case in some strata, the color is unaltered, the weapons have a glossy surface, and a lustre very unlike newly broken flints. In many cases also they have an incrustation of carbonate of lime and small dendritic markings. Moreover, it must be remembered, that when M. Boucher de Perthes' work was published, the weapons therein described were totally unlike anything then known. Since that time, however, not only have similar implements been found in various parts of England and France, but as already mentioned it has since come to light that similar weapons were in two cases actually described and figured in England many years ago, and that in both these instances they were found in association with the bones of ex- tinct animals.

On this point, therefore, no evidence could be more conclusive.

It has, however, been suggested that though the worked flints are really found by the workmen in the mammaliferous gravel, they may perhaps be comparatively recent, and have gradually inserted themselves from above by the force of gravity. Here however, again, I cannot do better than quote from the writer in Blackwood, "that a few minutes' inspection of the beds containing and overlying the flint implements of the Somme will assure any observer that they are entirely destitute of the imagined crevices, and are moreover altogether too compact and immoveable to admit of any such insinuation or percolation of surface objects."

Taking all these circumstances into consideration, it cannot be doubted that the flint implements really belong to the same age as the sands and gravels in which they occur.

Perhaps the most striking peculiarity of these weapons is, that they are never polished, not a single specimen having presented a trace of grinding; while, on the other hand, the implements of the later stone period, those which occur in burial-places, river beds, &c., are always carefully polished.

As regards their form, they are grouped by Mr. Evans under three heads:

"1. Flint flakes, apparently intended for arrowheads, or knives."

"2. Pointed weapons, analogous to lance or spear heads."

"3. Oval or almond-8haped implements, presenting a cutting edge all round."

The flakes offer no special peculiarities. The mode of their manufacture has already been described and illustrated (Nat. Hist. Rev. Oct. 1861),[6] and similar articles have been used by savages in all ages and countries, where flint or obsidian was obtainable.

The implements of the other two forms, which, however, pass almost imperceptibly into one another, are on the contrary quite unlike any of those belonging to the last or polished stone-period. The nearest approach to them is made by the small and rude implements found in the Danish Kjökkenmöddings,[7] but these again have a peculiar form, and would be at once distinguished by any experienced observer. During my last visit to Abbeville, I was much interested by finding, in the museum of M. Boucher de Perthes, a few small hatchets, which, both in shape and size, very closely resembled those which are found in the Danish Kjökkenmöddings, but all of these belonged to the later or post-elephantine period. It is, I think, probable that similar axes will be found in other countries, but that they have generally escaped notice hitherto on account of their rudeness.

Up to the present time no bones of men have been found in the strata containing the flint implements. This, though it has appeared to some so inexplicable as to throw a doubt on the whole question, is, on consideration, less extraordinary than it might at first sight appear to be. If, for instance, we turn to other remains of human settlements, we shall find a repetition of the same phenomenon. Thus in the Danish refuse-heaps, where worked flints are a thousand times more plentiful than in the St. Acheul gravel, human bones are of the greatest rarity. In this case, as in the Drift age, mankind lived by hunting and fishing, and could not therefore be very numerous. In the era however of the Swiss lake habitations, the case was different. M. Troyon estimates the population of the "Pfahlbauten" during the Stone age as about 32,000; in the Bronze era, 42,000. On these calculations, indeed, even their ingenious author would not probably place much reliance: still, the number of the Lake villages already known is very considerable; in four of the Swiss lakes only, more than 70 have been discovered, and some of them were of great extent: Wangen, for instance, being, according to M. Lohle, supported on more than 40,000 piles. Yet, if we exclude a few bones of children, only five skeletons have been obtained from all these settlements taken together. The number of flint implements obtained hitherto from the drift of the Somme valley, is not estimated at more than 3000; the settlement at Concise alone (Lake of Neufchatel) has supplied about 24,000, and yet has not produced a single human skeleton. (Rapport a la Commission des Musées, October 1861, p. 16). Probably this absence of bones is almost entirely attributable to the habit of burying; the instinct of man has long been in most cases to bury his dead out of his sight; still, so far as the drift of St. Acheul is concerned, the difficulty will altogether disappear if we remember that no trace has ever yet been found of any animal as small as a man. The larger and more solid bones of the elephant and rhinoceros, the hippopotamus, ox and stag[8] remain, but every vestige of the smaller bones has perished. Till we find the remains of the dog, boar, roedeer, badger, and other animals which existed dining the drift period, we cannot much wonder at the entire absence of human skeletons.

In all the other places where flint implements have occurred they have been very rare (except perhaps at Hoxne), and though the ascertained mammalian fauna is not everywhere quite so restricted as at St. Acheul, still very few small animals have as yet occurred.

It is useless to speculate as to the use made of these venerable weapons. Almost as well might we ask to what would they not be applied. Infinite as are our instruments, who would attempt even at present to say what was the use of a knife. But the primitive savage had no such choice of tools; we see before us perhaps the whole contents of his workshop; and with these weapons, rude as they seem to us, he may have cut down trees, scooped them out into canoes, grubbed up roots, killed animals and enemies, cut up his food, made holes in winter through the ice, prepared firewood, built huts, and in some cases at least they may have served as slingstones. When, however, we shall have considered the physical evidence as to the alien condition of the country, and the contemporary animals, we shall better be able to form a conception of the habits of these our long lost progenitors.

For I have as yet but partly answered the second of the two questions with which we started. Even admitting that the flint hatchets are coeval with the gravel in which they occur, it remains to be shown that the bones of the extinct animals belong also to the same period. With reference indeed to two of those ordinarily quoted as belonging to this group, there may still be some little doubt. It seems very questionable whether any remains really belonging to the cave-bear have ever occurred in these beds, as will presently be mentioned, and though a few tusks of the hippopotamus have been found, yet (as this genus never occurs in the corresponding beds of Germany) it is possible that they may have been washed out of some older stratum.

But as regards the elephant and the rhinoceros the case is different. There is not the slightest reason to doubt that they really belong to this period and, in the case of the rhinoceros, we have the evidence of M. Baillon that the bones of the hind leg of a rhinoceros were found, at Menchecourt, in their relative situations, while the rest of the skeleton was discovered at a little distance. In this case, therefore, the body must have been entombed before the decay of the ligaments. Sir Cornewall Lewis, however, in his interesting and able, even if unsatisfactory work, on the Astronomy of the Ancients, argues that even if we must give an affirmative answer to the two first questions, and admit the coexistence of man in Western Europe with the mammoth and tichorine rhinoceros; still we may do this by bringing these animals down to a later period, as well as by carrying man back to an earlier one.

Fairly admitting this, let us now, therefore, turn to the physical evidence in the case, and see how far this will enable us to give any, and if so what, answer, to the third of the above questions.

In this part of the subject I shall be principally indebted for my facts to Mr. Prestwich, who has long studied the quaternary beds, and has done more than any other man to render them intelligible. In most of his conclusions I entirely concur, but I may perhaps be permitted to mention that though the following statements are given on his authority, I have verified almost the whole of them for myself, having had the advantage of visiting, with him and Mr. Evans, many localities not only in the valley of the Somme, but also along the banks of the Seine and its tributaries.

Fig. 4, gives a section across the valley of the Somme at Abbeville, taken from Mr. Prestwich's first paper.[9] We should get almost the same arrangement and position of the different beds, not only at St. Acheul, but elsewhere along the valley of the Somme, wherever the upper beds have not been removed by subsequent action of the river. Even at St. Valery, at the present mouth of the river, we found a bed of gravel at a considerable height above the level of the sea. This would seem to show that at the period of these high level gravels, the channel was narrower than it is at present, as indeed we know to have been the case even in historical times. So early as 1605 our countryman Verstegan[10] pointed out that the waves and tides were eating away our coasts. Sir C. Lyell gives much information on this subject, and it appears that even as lately as the reign of Queen Elizabeth, the town of Brighton was situated on the site now occupied by the Chain Pier.

Mr. Prestwich has shown[11] that a section, similar to that of the Somme, is presented by the Lark, Waveney, Ouse, &c. while it is well shown also along the banks of the Seine. Probably, indeed, it holds good of most of our rivers, that along the sides of their valleys are patches of old gravels left by the stream at various heights, before they had excavated the channels to their present depth. Mr. Prestwich considers that the beds of sand and gravel can generally be divided into two more or less distinct series, one continuous along the bottom of the valleys and rising little above the water level; the other occurring in detached masses at an elevation of 50 to 200 feet above the valley. Rather, perhaps, these are the two extremes of a series, once continuous, but now almost always presenting some interruption. A more magnified view of the strata at St. Acheul, near Amiens, is shown in Fig. 2. The upper layer of vegetable soil having been removed.

1. A bed of brick earth from four to five feet in thickness, and containing a few angular flints.

2. Below this is a thin layer of angular gravel, one to two feet in thickness.

3. Still lower is a bed of sandy marl, five to six feet thick, with land and fresh water shells, which though very delicate, are in most cases perfect.

4. At the bottom of all, and immediately overlying the chalk, is the bed of subanguar gravel in which the flint implements are found.

In the early Christian period this spot was used as a cemetery: the graves generally descend into the marly sand, and their limits are very distinctlv marked. Fig. 2; an important fact, as showing that the rest of the strata have lain undisturbed for 1500 years. The coffins used were sometimes made of hard chalk, sometimes of wood, in which latter case the nails and clamps only remain, every particle of wood having perished, without leaving even a stain behind. Passing down the hill towards the river, all these strata are seen to die out, and we find ourselves on the bare chalk; but again at a lower level occurs another bed of gravel, resembling the first, and capped also by the bed of brick earth which is generally known as loess.

These strata, therefore, are witnesses; but of what? Are they older ihan the valley, or the valley than they? are they the result of causes still in operation, or the offspring of cataclysms now, happily, at an end. According to the accomplished writer in Blackwood their testimony is but unsatisfactory. Examined they tell one tale; cross-examined they contradict themselves, until the jury falls back hopelessly on a verdict of "not proven."

If, indeed, we can show that the present river, somewhat swollen perhaps, owing to the greater extension of forests in ancient times, and by an alteration of climate, has excavated the present valley, and produced the strata above enumerated; then "the suggestion of an antiquity for the human family so remote as is here implied, in the length of ages required by the gentle rivers and small streams of eastern France to erode its whole plain to the depths at which they now flow, acquires, it must be confessed, a fascinating grandeur, when, by similitude of feature and geology, we extend the hypothesis to the whole north-west frontiers of the continent, and assume, that from the estuary of the Seine to the eastern shores of the Baltic, every internal feature of valley, dale and ravine—in short, the entire intaglio of the surface—has been moulded by running waters, since the advent of the human race."

But, on the other hand, it has been maintained that the pliant facts may be read as "expressions of violent and sudden mutations, only compatible with altogether briefer periods." The argument of the Paroxysmist, I still quote from Blackwood, would probably be something like the following:—

"Assuming the pre-existing relief, or excavation rather, of the surface to have approximated to that now prevailing, he will account for the gravel by supposing a sudden rocking movement of the lands and the bottom of the sea of the nature of an earthquake, or a succession of them, to have launched a portion of the temporarily uplifted waters upon the surface of the land."

Having thus heard the arguments of Counsel, let us now call the witnesses to speak for themselves.

Taking the section at St. Acheul and commencing at the bottom, we have first of all the subangular gravel throughout which, though especially at the lower part, the flint implements occur.

A similar bed may be found here and there all along the valley of the Somme; at St. Acheul it is about 90 ft. above the present river level; at Moulin Quignon, near Abbeville, the same; while at Picquigny and at Cæsar's Camp near Liercourt, we found it at a height of 150 feet. Though only occurring in places, this gravel is so similiar in composition and contents, that we seem justified in assuming it to have been at one time continuous; and we may almost take the section, Fig. 4, as representing generally a section taken anywhere across the valley, only bearing in mind that through the action of subsequent causes, the gravel and the beds covering it have been in most cases removed. Nor is this a phenomenon peculiar to the Somme. During our last excursion we visited many gravel pits holding a similar relation to the Seine, while Mr. Prestwich in his recent communication to the Royal Society,[12] extends the same statement to many other rivers in England and France, the greatest height of the gravel above the present river level, varying however in different cases. At St. Acheul and in several other places this bed of gravel, which for the future we will call the high level gravel, is separated from the low level gravel by a bare tract of the underlying rock. We do, however, sometimes find beds at intermediate levels, and must therefore consider the upper level, and lower level gravels as the extremes of a continuous series, rather than as strata separated by an intermediate and different condition of the valley.

The mammalia found in this upper level gravel are but few; the Mammoth, the Rhinoceros tichorhinus, with species of Bos, Cervus, and Equus are almost the only ones which have yet occurred at St. Acheul, but beds of the same age in other parts of France have, in addition, supplied us with remams of the Bear, of a species of Tiger, of the Hyæna spelæa, Cervus tarandus priscus, of a species of Dog, of the Musk Ox, and the Hippopotamus. The Mollusca however are more numerous; they have been identified by Mr. J. G. Jeffreys, who finds in the upper level gravel 43 species, all of them land or freshwater forms, and all belonging to existing species. It is hardly necessaiy to add that these shells are not found in the coarse gravel, but only here and there, where quieter conditions, indicated by a seam of finer materials, have preserved them from destruction. Here, therefore, we have a conclusive answer to the suggestion that the gravel may have been heaped up to its present height by a sudden irruption of the sea. In that case we should find some marine remains; but as we do not, as all the fossils belong to animals which live on the land, or inhabit fresh waters, it is at once evident that this stratum not being subaerial, must be a freshwater deposit.

But the gravel itself tells us even more than this: the river Somme flows through a country in which there are no rocks older than the chalk, and the gravel in its valley consists entirely of chalk flints and tertiary debris.[13] The Seine, on the other hand, receives tributaries which drain other formations. In the valley of the Yonne we find fragments of the crystalline rocks brought from the Morvan.[14] The valley of the Oise is in this respect particularly instructive: "de Maquenoise à Hirson[15] la vallée en présente que des fragments plus ou moins roulés des roches de transition que traverse le cours de la Rivière. En descendant à Etréaupont, on y trouve des calcaires jurassiques et des silex de la craie, formations qui ont succédé aux roches anciennes. A Guise, le dépôt erratique .......... est composé de quartzites et de schistes de transition de quelques gruès plus recent, de silex de la craie, et surtout de quartz laiteux, dont le volume varie depuis celui de la tête jusqu' à celui de grain de sable .... Au delà les fragments de roches anciennes deminuent graduellement en volume et en nombre." At Paris we found the granitic debris brought down by the Yonne to form a notable proportion of the gravel; and at Précy, near Creil on the Oise, the fragments of the ancient rocks were abundant; but lower down the Seine at Mantes, they had both diminished very much in quantity, and at Rouen and Pont de l'Arche we saw none, though a longer search would doubtless have shown us fragments of them. This case of the Oise is however interesting, not only on account of the valuable evidence contained in the above quotation, but because, though it flows, as a glance at the map will show, immediately across and at right angles to the Somme, yet none of the ancient rocks which form the valley of the Oise, have supplied any debris to the valley of the Somme: and this though the two rivers are at one point within six miles of one another, and separated by a ridge of only 80 feet in height.

The same division occurs between the Seine and the Loire: "bien que la ligne de partage des eaux de la Loire et de la Seine, entre St. Amand (Nièvre) et Artenay, au nord d'Orléans, soit a peine sensible, aucun débris de roches venant du centre de la France, par la vallée de la Loire n'est passé dans le bassin de la Seine."[16]

In the Vivarais near Auvergne, "Les dépôts diluviens, sont composés des mêmes roches que celles que les rivières actuelles entrainent dans les vallées, et sont les débris des seules montagnes de la Lozin, du Tanargue et du Mézene, qui entourent le bassin du Vivarais.[17]

Again,

"Le diluvium des vallées de l'Aisne et de l'Aire ne renferme que les débris plus ou moins roulés des terrains que ces rivières coupent dans leur cours."[18]

Other instances of the same law may be quoted; Mr. Prestwich has found it to hold good in England, but as it is an important link in the chain of evidence on which his views depend, it seemed better to take the facts from other observers. The conclusion deduced by M. D'Archiac from the consideration of these observations, and specially from those concerning the valley of the Seine, was "que les courants diluviens ne venaient point d'une direction unique mais qu'ils convergaient des bords du bassin vers son centre, suivant les depressions préexistantes, et que leur élévation ou leur force de transport ne suffisait pas pour faire passer les debris qu'ils charriaient d'une de ces vallées dans l'autre."[19]

Considering, however, all these facts, remembering that the constituents of the upper level gravels are, in all cases, derived from beds now in situ along the valley, that they have not only followed the lines of these valleys, but have done so in the direction of the present waterflow, and without in any case passing across from one river system to another, we may surely, I think, follow Mr. Prestwich in his conclusion that these gravels have been brought down, and deposited by the present rivers.

The sandstone blocks which occur in the gravel appear indeed at first sight to be irreconcileable with any such hypothesis. In some fits they occur frequently, and are of considerable size; the largest have myself seen is represented in the section, Fig. 1, taken close to the railway station at Joinville. It was 8 ft. 6 inches in length, with a width of 2 ft. 8 in., and a thickness of 3 ft. 4 in. Even when we remember that at the time of its deposition the valley was not excavated to its present depth, we must still feel that a body of water with power to move such masses as these must have been very different from any floods now occurring in those valleys, and might fairly perhaps deserve the name of a cataclysm. But whence could we obtain so great a quantity of water? We have already seen that the gravel of the Oise, though so close, is entirely different from that of the Somme, while that of the Seine again is quite different from that of any of the neighbouring rivers. These rivers therefore cannot have drained a larger area than at present; the river systems must have been the same as now. Nor would the supposition after all account for the phenomena. We should but fall from Scylla into Charybdis. Around the blocks we see no evidence of violent action; in the section at Joinville, the grey subangular gravel passed under the large block abovementioned, with scarcely any alteration. But a flood which could bring down so great a mass would certainly have swept away the comparatively light and moveable gravel below. We cannot therefore account for the phenomena by aqueous action, because a flood which would deposit the sandstone blocks would remove the underlying gravel, and a flood which would deposit the gravel would not move the blocks. The Deus ex machinâ has not only been called in most unnecessarily, but when examined turns out to be but an idol after all.

Driven, then, to seek some other explanation of the difficulty, Mr. Prestwich falls back on that of floating ice. Here we have an agency which would satisfactorily explain all the difficulties of the case. The "packing" and propelling action of ice would also account for some irregularities in the arrangement of the beds which are very difficult otherwise to understand. We are, indeed, irresistibly reminded of the figure given by Sir Charles Lyell[20] from a view taken by Lieut. Bowen, or the boulders drifted by ice on the shores of the St. Lawrence. I wish that I could transfer this view to our pages; but Sir C. Lyell's work must be in the hands of almost every geologist, and it will, perhaps, therefore, be unnecessary for me to quote the accompanying description, accurately as it portrays what must, I think, have been taking place in the valley of the Somme thousands of years ago, just as it does in the St. Lawrence at the present time. Nor does the physical evidence only, point to a more arctic climate during the period now under consideration; the fauna also tells the same tide. The Mollusca, indeed, do not afford much evidence, but though mainly the same as those now living in the country, they have rather northern tendencies, 85 out of the 43 species being at present found in Finland.[21] With the mammalia the case is different. The Reindeer, the Musk Ox, the Norwegian Lemming, and the still more Arctic Myodes torquatus, all of which occur in the drift, are decidedly indications of a cold climate. The circumstances attending the discovery of the Tichorhine rhinoceros in Siberia, the fact of the Mammoth of the Lena being enveloped in ice so soon after death that the flesh had not had time to decay, as well as the manner in which these extinct Pachydermata were provided against cold, all tend to show that the Elephas primigenius and the Rhinoceros tichorhinus, unlike their congeners of to-day, were inhabitants rather of Arctic than Tropical climates. That there are in this argument two weak points, I must frankly admit. In the first place, it may be objected that the Hippopotamus major, of which bones occur in the drift, could scarcely nave existed in a cold country. Mr. Prestwich, indeed, suggests that this species may, perhaps, like its gigantic relatives, have been fitted to flourish in an arctic climate. But there is some difference of opinion as to its occurrence; it has not yet been found in the "diluvium" of Germany, (Sir C. Lyell, Supplement to Manual, 1857, p. 8), and though remains of it have undoubtedly occurred in the drift gravel of the Somme, there is some reason to believe that they are not in quite the same condition as the bones of the Elephant and Rhinoceros; it is possible, therefore, that they may belong, as Dr. Falconer suggests, to an anterior period. Secondly, it might also be argued, that the animals above- mentioned, though at present confined to the colder regions, may once have lived in temperate countries. Until lately we should have regarded the Tiger as an essentially tropical animal; yet it is now known to be common in the neighbourhood of Lake Aral, in the forty-fifth degree of north latitude; and "the last Tiger killed, in 1828, on the Lena, in lat. 521/4°, was in a climate colder than that of St. Petersburg and Stockholm."[22]

While, however, admitting these two possible objections, it is still, I think, felt by most Palæontologists, that though the presence of one Arctic species would scarcely perhaps justify any very decided inference as to climate, still that the co-existence of such a group as this; the musk ox, the reindeer, the lemming, the Myodes torquatus, the Siberian mammoth, and its faithful companion the woolly haired rhinoceros, decidedly indicates, even though it may not prove, the existence of a climate unlike that now prevailing in Western Europe. But when, in addition, we get the physical evidence brought forward by Mr. Prestwich, the disturbed condition of the beds, and the presence of the large blocks, the inference is much strengthened. The amount of difference still remains to be ascertained. Taking the present range of the Musk ox and Reindeer as his guides, Mr. Prestwich assumes a difference in the mean winter temperature of 19° to 29°. While, however, admitting the probability of a somewhat greater winter cold, we are not, I think, yet in a position to estimate the amount of change.

It must always be borne in mind that the temperature of Western Europe is at present exceptionally mild; if we go either to the east or west, to Canada or Siberia, we find countries under the same latitude as London and Paris suffering under a far more severe climate.

The river St. Lawrence, to which I have pointed as throwing so much light on the transport of the blocks now in question, is actually in a lower latitude than the Seine or the Somme. Moreover, geologists are agreed that at the period of the boulder day, a period immediately preceding that now under consideration, the cold in Western Europe must have been far more intense than it is at present. The subject is treated at length in an excellent paper by Mr. Hopkins[23] (then President of the Geological Society), and it is admitted (p. 61) that many of our rivers have probably followed their present directions "ever since the glacial period." Mr. Prestwich's hypothesis involves therefore in reality no change of climate. He only supposes that, in this early period of our rivers, the temperature of Western Europe agreed with that which had preceded, rather than with that which now prevails; or rather, perhaps, that, in this intermediate period, the temperature had neither the extreme severity of the glacial era, nor the exceptional mildness of modern times.

But though diminishing the improbability of the suggestion, these considerations throw no light on the alteration of the conditions which must have taken place to produce an alteration of climate so great as that inferred by Mr. Prestwich.

The principal causes which have been suggested are the following:—

1stly. A possible variation in the intensity of solar radiation.
To this Mr. Hopkins sees no a priori objection; but he does not feel disposed to attach much weight to it, because it is "a mere hypothesis framed to account for a single and limited class of facts, and unsupported by the testimony of any other class of allied, but independent phenomena."
2ndly. Admitting the proper motion of the sun, it has been suggested that we may have recently passed from a colder into a warmer region of space.
I must refer to Mr. Hopkins' paper for his objections to this suggestion, which certainly appear to "render the theory utterly inapplicable to the explanation of the changes of temperature at the more recent geological epochs." (l. c. p. 62.)
3rdly. The effect of an altered position of land and water.
This cause, which has been advocated by Sir C. Lyell with so much ability, would no doubt have the effect attributed to it, but it seems scarcely applicable to the present difficulty, because the geography of Western Europe must have been nearly the same during the period under consideration, as it is at present. The existence of a continent north of Scandinavia and Scotland, might indeed go far towards accounting for the phenomena; but to this suggestion we must make the same answer as to the first.
4thly. An alteration in the earth's axis.
The possibility of such a change has indeed been denied by many astronomers. My father, on the contrary, in a letter to Sir C. Lyell,[24] has maintained that it would necessarily follow from upheavals and depressions of the earth's surface, if only they were of sufficient magnitude. This suggestion, however, like the preceding, involves immense geographical changes, and would therefore necessarily have required an enormous lapse of time.
5thly. Mr. Hopkins, in the paper to which I have already alluded, inclines to find another solution of the difficulty in the supposition that the Gulf Stream did not at this period warm the shores of Europe "A depression of 2000 feet would," he says, convert the Mississippi into a great arm of the sea, of which the present Gulf of Mexico would form the southern extremity, and which would communicate at its northern extremity with the waters occupying the . . . . . . great valley now occupied by the chain of lakes." In this case the Gulf Stream would no longer be deflected by the American coast, but would pass directly up this channel into the Arctic Sea; and as every great ocean current must have its counter current, it is probable that there would be a flow of cold water from the north, between the coasts of Norway and Greenland. The absence of the gulf stream would probably lower the January temperature of Western Europe 10 degrees, while the presence of a cold current from the North would make a farther difference of about three or four degrees;[25] an alteration of the climate which would apparently be sufficient to account for all the phenomena. This theory, Mr. Hopkins considers as no mere hypothesis, but as necessarily following from the submergence of North America, which has been inferred from evidence of a different nature.

In this case, of course, the periods of great cold in Europe and in America must have been successive and not synchronous; and it must also be observed, that in this suggested deflection of the Gulf Stream Mr. Hopkins was contemplating a period anterior to that of the present rivers. For if we are to adopt this solution of the difficulty, what an immense time would be required. If, when the gravels and loëss of the Somme and the Seine were being deposited, the Gulf Stream was passing up what is now the Valley of the Mississippi, then it follows that the formation of the loëss in that valley and its delta, an accumulation which Sir C. Lyell has shown to require a period of about 100,000 years, would be subsequent to the excavation of the Somme Valley, and to the presence of man in Western Europe.

Thus, therefore, though the alteration of climate apparently indicated by the zoological contents and the physical condition of the beds, might by increasing the power of the floods, add to the erosive action of the river, and thus diminish on the one hand the time required for the excavation of the valley, still the very alteration itself appears, on the other hand, to require an even greater lapse of time.

But even if the presence of the sandstone blocks, and the occasional contortions of the strata, far from being objections to Mr. Prestwich's views, seem rather to speak strongly in their favour, still the height which the gravels sometimes attain above the pre- sent water-level, is at first sight a great difficulty, and we cannot wonder therefore that these beds have generally been attributed to violent cataclysms, owing to the emergence of the land, to astronomical causes, and even to the elevation of the Andes.

M. Boucher de Perthes has always been of this opinion. "Ce coquillage, cet éléphant, cette hache, ou la main qui la fabriqua, furent donc témoins du cataclysme qui donna à notre pays sa configuration présente."[26]

M. O. D'Orbigny, observing that the fossils found in these quaternary beds are all either of land or freshwater animals, correctly dismisses the theory of any marine action, and expresses himself as follows:—"En effet l'opinion de la plupart des géologues est que les cataclysmes diluviens ont eu pour causes prédominantes de fortes oscillations de l'éncorce terrestre, des soulèvements de montagnes au milieu de l'ocean, d'où seraient résultées de grandes érosions. Par conséquent les puissants courants d'eau marine, auxquels on attribue ces érosions diluviennes, auraient dû laisser sur les continents des traces authentiques de leur passage, tels que de nombreux débris de coquilles, de poissons et autres animaux marins analogues à ceux qui vivent actuellement dans la mer. Or, ainsi que M. Cordier l'a fait remarquer depuis longtemps à son cours de géologie, rien de semblable n'a été constaté. Sur tous les points du globe où l'on a étudié les dépôts diluviens, on a reconnu que, sauf quelques rares exceptions très contestables, il n'existe dans ces depôts aucun fossile marin: ou bien ce sont des fossiles arrachés aux terrains préexistants, dont la dénudation a fourni les matériaux qui composent le diluvium. En sorte que les dépôts diluviens semblent avoir eu pour cause des phénomènes météorologiques, et paraissent être le résultat d'immenses inondations d'eau douce, et non d'eau marine, qui, se précipitant des points élevés vers la mer, auraient dénudé une grande partie de la surface du sol, balayé la généralité des êtres organisés et pour ainsi dire nivelé, coordonné les bassins hydrographiques actuels."[27] (See also D'Archiac, l. c. passim). It is unnecessary for me to point out bow entirely these views differ from the one here advocated, and which we owe mainly to the persevering researches of Mr. Prestwich. Such cataclysms as those supposed by Mr. D'Orbigny, and many other French Geologists, even if admitted, would not account for the results before us. We have seen that the transport of materials has not followed any single direction, but has in all cases followed the lines of the present valleys, and the direction of the present waterflow; that the rocks of one valley are never transported into another; that the condition of the loess is irreconcileable with a great rush of water; that the mammals and molluscs are the same throughout the period; while, finally, the perfect preservation of many of the most delicate shells is dear proof that they have not been subjected to any violent action.

We must, moreover, bear in mind that the gravels and sands are themselves both the proof and the results of an immense denudation. In a chalk country, such as that through which the Somme flows, each cubic foot of flint, gravel or sand, represents the removal of at the very least twenty cubic feet of chalk, all of which, as we have already seen, must have been removed from the present area of drainage. In considering, therefore, the formation of these upper and older gravels, we must not picture to ourselves the original valley as it now is, but must, in imagination, restore all that immense mass of chalk which has been destroyed in the formation of the lower level gravels and sands. Mr. Prestwich has endeavoured to illustrate this by a program,[28] and I must once more repeat that this is no mere hypothesis, since the mass of sand and gravel cannot have been produced without an immense removal of the chalk.

Far, therefore, from requiring an immense flood of water, two hundred feet in depth, the accumulation of the gravel may have been effected by an annual volume of water, differing little from that of the present river.

A given quantity of water will, however, produce very different effects, according to the manner in which it passes. "We learn from observation, that a velocity of three inches per second at the bottom will just begin to work upon fine clay fit for pottery, and however firm and compact it may be, it will tear it up. Yet no beds are more stable than clay when the velocities do not exceed this: for the water even takes away the impalpable particles of the superficial clay, leaving the particles of sand sticking by their lower half in the rest of the clay, which they now protect, making a very permanent bottom, if the stream does not bring down gravel or coarse sand, which will rub off this very thin crust, and allow another layer to be worn off. A velocity of six inches will lift fine sand, eight inches will lift sand as coarse as linseed, twelve inches will sweep along fine gravel, twenty-four inches will roll along rounded pebbles an inch diameter, and it requires three feet per second at the bottom to sweep along shivery angular stones of the size of an egg."[29]

If, therefore, we are justified in assuming a colder climate than that now existing, we should much increase the erosive action of the river, not only because the rains would fall on a frozen surface, but because the rainfall of the winter months would accumulate on the high grounds in the form of ice and snow, and would every spring produce floods much greater than any which now occur.

We now come to the light-coloured sandy marl (Fig. 2). It is described by Mr. Prestwich as follows, "White siliceous sand and light-coloured marl, mixed with fine chalk grit, a few large sub- angular flints, and an occasional sandstone block, irregular patches of flint gravel, bedding waved and contorted, here and there layers with diagonal seams, a few ochreous bands, portions concreted. Sand and freshwater shells common, some mammalian remains."

In the pits at Amiens this bed is generally distinct from the underlying gravels, owing perhaps to the upper portion of the gravel having been removed; but in several places (Précy, Ivry, Bicêtre, &C.) we saw this section complete, the gravel coarser below becoming finer and finer, and at length passing above into siliceous sand. These sections evidently indicate a loss of power in the water at these particular spots, rapid enough at first to bring down large pebbles, its force became less and less until at length it was only able to deposit fine sand. This, therefore, appears to indicate a change in the course of the river, and gradual excavation of the valley, which, by supplying the floods with a lower bed, left the waters at this height with a gradually diminishing force and velocity.

The upper part of the section at St. Acheul consists of brick earth, passing below into angular gravel, while between this and the underlying sandy marl is sometimes a small layer of darker brick earth. These beds, however, vary much even in adjoining sections. Taken as a whole they are regarded by Mr. Prestwich as the representatives of that remarkable loamy deposit which is found overlying the gravels in all these valleys of Northern Prance, and which, as the celebrated "loëss" of the Rhine, attains a thickness of 800 feet. The greatest development of it which I have seen was in a pit in the Rue de la Chevalerie, near Ivry, where it was twenty-two feet thick, some of which however may have been reconstructed loëss brought down by rain from the higher ground in the immediate neighbourhood.

Assuming that this loëss is composed of fine particles deposited from standing or slowly moving waters, we might be disposed to wonder at not finding in it any traces of vegetable remains. We know, however, from the arrangement of the nails and hasps that in some of the St. Aeheul tombs wooden coffins were used, while the size of the nails shows that the planks must have been tolerably thick; yet in these cases every trace of wood has been removed, and not even a stain is left to indicate its presence.

Such is a general account of those gravel pits which lie at a height of from 80 to 150 feet above the present water level of the valleys, and which along the Somme are found in some places even at a height of 200 feet.

Let us now visit some of the pits at the lower levels. At about thirty feet lower, as for instance at Menchecourt, near Abbeville, and at St. Roch, near Amiens, where the gravels slope from a height of about sixty feet down to the valley, we find almost a repetition of the same succession; coarse subangular gravel below, finer materials above. So similar, indeed, are these beds to those already described, both in constitution and in the animal remains they contain, that it will be unnecessary for me to give any farther description of them.

Finally, the lowest portion of the valley is at present occupied by a bed of gravel, covered by silt and peat, which latter is in some places more than twenty feet thick, and is extensively worked for fuel. These strata have afforded to the antiquaries of the neighbourhood, and especially to M. Boucher de Perthes, a rich harvest of interesting relics belonging to various periods. The depth at which these objects are found has been carefully noted by M. Boucher de Perthes.

"Prenant" he says, "pour terme moyen du sol de la vallée, une hauteur de 2 mètres audessus du niveau de la Somme, c'est à 30 à 40 centimètres de la surface qu'on rencontre le plus abondamment les traces du moyen-âge. Cinquante centimètres plus bas, on commence à trouver des déris romains, puis gallo-romains. On continue à suivre ces derniers pendant un mètre, c'est a dire jusqu'au niveau de la Somme. Après eux, viennent les vestiges gaulois purs qui descendent sans interruption jusqu'à près de 2 mètres audessous de ce niveau, preuve de la longue habitation de ces peuples dans la vallée. C'est à un mètre plus bas, ou a 4 mètres environ audessous de ce même niveau, qu'on arrive au centre du sol que nois avons nommé Celtique, celui qui foulèrent les Gaulois primitives ou les peuples qui les précédèrent;" and which belonged therefore to the ordinary stone period. It is, however, hardly necessary to add that these thicknesses are only given by M. Boucher de Perthes "comme terme approximatif"

The "Antiquités Celtiques" was published several years before the Swiss Archæologists had made us acquainted with the nature of the Pfahlbauten; but, from some indications given by M. Boucher de Perthes, it would appear that there must have been, at one time, lake-habitations in the neighbourhood of Abbeville. He found considerable platforms of wood, with large quantities of bones, stone implements, and handles closely resembling those which come from the Swiss lakes.

These weapons cannot for an instant be confounded with the ruder ones from the drift gravel They are ground to a smooth surface and a cutting edge, while the more ancient ones are merely chipped, not one of the many hundreds already found having shown the slightest trace of grinding. Yet though the former belong to the stone age, to a time so remote that the use of metal was apparently still unknown in Western Europe, they are separated from the earlier weapons of the upper level drift by the whole period necessary for the excavation of the Somme Valley, to a depth of more than 100 feet.

If, therefore, we get no definite date for the arrival of man in these countries, we can at least form a vivid idea of his antiquity. He must have seen the Somme running at a height of, in round numbers, a hundred and fifty feet above its present level. From finding the hatchets in the gravel up to a level of a hundred feet, it is probable that he dates back in Northern France almost, if not quite, as long as the rivers themselves. The face of the country must have been indeed unlike what it is now. Along the banks of the rivers ranged a savage race of hunters and fishermen, and in the forests wandered the mammoth, the two-horned, woolly, rhinoceros, a species of tiger, the musk ox, the reindeer, and the urus.

Yet the geography of France cannot have been very different from what it is at present. The present rivers ran in their present directions, and the sea even then lay between the Somme and the Adur, though the channel was not so wide as it is at present.

Gradually the river deepened its valley; ineffective, or even perhaps constructive, in autumn and winter, the melting of the snows turned it every spring into a roaring torrent. These floods were probably more destructive to animals even than man himself; while, however rude they may have been, our predecessors can hardly be supposed to have been incapable of foreseeing and consequently escaping the danger. While the water, at an elevation of 160 feet above its present level, as for instance at Liercourt, had sufficient force to deposit coarse gravel; at a still higher level it would part with finer particles, and would thus form the loëss which, at the same time, would here and there receive angular flints and shells brought down from the hills in a more or less transverse direction by the rivulets after heavy rains.

As the valley became deeper and deeper the gravel would be deposited at lower and lower levels, the loëss always following it;[30] thus we must not consider the loëss as a distinct bed, but as one which was being formed during the same time, though never at the same place as the beds of gravel. Fig. 3, I have given an imaginary diagram, the better to illustrate my meaning; the loëss is indicated by letters with a dash and is dotted, while the gravels are represented as rudely stratified. In this case I suppose the river to have run originally on the level (a), and to have deposited the gravel (a) and the loëss (a′); after a certain amount of erosion which would reduce the level to (b), the gravel would be spread out at b, and loess at (b′), Similarly the loëss (c′) would be contemporaneous with the gravel (c).

Thus while in each section the lower beds would of course be the oldest, still the upper-level gravels as a whole would be the most ancient, and the beds lying on the lower parts of the valley the most modern.

For convenience I have represented the sides of the valley as forming a series of terraces; and though this is not actually the case, there are several places in which such terraces do occur.[31]

It is, however, well known that rivers continually tend to shift their courses; nor is the Somme any exception to the rule; the valley itself indeed may be comparatively straight, but within it the river winds considerably, and when in one of its curves, the current crosses "its general line of descent, it eats out a curve in the opposite bank, or in the side of the hills bounding the valley, from which curve it is turned back again at an equal angle, so that it recrosses the line of descent, and gradually hollows out another curve lower down in the opposite bank, till the whole sides of the valley, or river-bed, present a succession of salient and retiring angles." (Lyell, Principles, p. 206.) During these wanderings from one side of the valley to the other, the river continually undermines, and removes the gravels which at an earlier period it had deposited. Thus the upper-level gravels are now only to be found here and there, as it were in patches, while in many parts they have altogether disappeared, as, for instance, on the right side of the valley between Amiens and Pont Rémy, where hardly a trace of the high level gravels is to be seen.

At length the excavation of the valley was completed; the climate must have approached what it is now, and whether from this change, or whether perhaps yielding to the irresistible power of man, the great Pachydermata had become extinct. Under new conditions, the river, unable to carry out to sea the finer particles brought down from the higher levels, deposited them in the valley, and thus raised somewhat its general level, checking the velocity of the stream, and producing extensive marshes, in which a thick deposit of peat was gradually formed. We have, unfortunately, no reliable estimate as to the rate of formation of this substance, but on any supposition the production of a mass more than 20 feet in thickness must have acquired a very considerable period. Yet it is in these beds that we find the remains of the stone period. From the tombs at St. Acheul, from the Roman remains found in the peat near the surface of the ground, at about the present level of the river, we know that fifteen hundred years have produced scarcely any change in the configuration of the valley. In the peat, and at a depth of about 15 feet in the alluvium at Abbeville, are the remains of the stone period,[32] which we know from the researches in Denmark and Switzerland to be of an age so great that it can only be expressed in thousands of years. Yet all these are subsequent to the excavation of the valley; what antiquity then are we to ascribe to the men who lived when the Somme was but beginning its great task? No one can properly appreciate the time required who has not stood on the heights of Liercourt, Picquigny, or on one of the other points overlooking the valley: nor, I am sure, could any geologist return from such a visit without an overpowering sense of the change which has taken place, and the enormous time which must have elapsed since the first appearance of man in Western Europe.

We cannot but ask what manner of men they were who lived in these distant times: did they resemble the present inhabitants of Arctic Europe, who were regarded by a quaint old writer of the last century as being even lower than Apes,[33] or did the celebrated Neanderthal skull (Nat. Hist. Review, Vol. I. p. 155) belong to this race of men? We may hope that the discovery of a skeleton will ere long enable us to answer this question; may the veteran antiquary of Abbeville himself be the fortunate finder of the first human bones in the drift!

But were these the first settlers in Europe? M. Lartet answers in the negative, and ingeniously attempts to construct a Palæontological Chronology. (Ann. Sci. Nat. iv.; Ser. V. xv. 6217.) The great cave-bear (Ursus spelæus) has been frequently found associated with man in caves, but its remains have, according to M. Lartet, not yet been found in the river drifts. The species is indeed quoted by Messrs. Buteux and Ravin, on whose authority it is also given by Messrs. Prestwich and Evans; but M. Lartet, after careful examination, not having been able to find the specimen originally attributed to this species, concludes that the Ursus spelæus perished at an earlier period, and that the Hyæna spelæa and the Felis spelæa belong only to the earliest beds of the drift. The caves, therefore, in which these animals have been found associated with the remains of men, indicate, he thinks, a still greater antiquity for the human race.

Negative evidence in Palæontology must indeed always be regarded with suspicion, but I may at least be permitted to repeat the opinion that it is not in a northern country and in a cold climate that we shall find the first traces of man. No nation would choose such an abode; civilised man, indeed, may prefer a temperate region, favourable to the exercise both of mind and body; but the savage will go where he can most readily satisfy savage wants; he will not therefore betake himself to temperate, still less to Arctic regions, until driven there by increasing density of population.

But are we justified in concluding that even the cave men were the earliest human settlers in Western Europe? Surely not. The whole history of Palæontoloy is a standing protest against such an assumption. We have not indeed as yet the materials to decide the question, but if we were to express any opinion on the subject, it would seem more philosophical to imagine that the genus Homo dates back to a period as ancient as the other widely-spread genera of Mammalia; and that wherever the bones of Deer, Elephants, Horses, Oxen and Dogs are to be found, there we may fairly expect ere long to discover also the remains of Man.

DESCRIPTION OF THE FIGURES.

Plate VII.—A flint instrument found near Abbeville; slightly reduced. Our artist has been so careful to present a faithful image of this interesting specimen, that he has even copied exactly my memorandum as to the place and date of its discovery.

Wood Engravings.

Fig. 1. Section taken in a pit close to the Joinville Station.
b. Red angular gravel, containing a veiy large sandstone block.
d. Grey subangular gravel.
Fig. 2. Section at St. Acheul near Amiens.
a. Brick earth, with a few angular flints.
b. Red angular gravel.
c. Marly sand, with land and freshwater shells.
d. Grey subangular gravel, in which the flint implements are found.
e. Coffin.
f. Tomb.
Fig. 3. Diagram to illustrate deposit of loëss and gravel.
a′ Loëss corresponding to a contemporaneous with gravel a
b′ Loëssb
c′ Loëssc
1. Level of valley at period a
2. b
3. present.
Fig. 4. Section across the valley of the Somme at Abbeville, after Prestwich; the length is however reduced to one-third.

  1. Phil. Transact. 1860.
  2. M. L'Abbé Cochet states (l. c. p. 8) that similar weapons have been found at Sotteville, near Rouen, and are deposited in the Musée d'Antiquités. There seems, however, to be some mistake about these specimens, at least M. Pouchet, who received us at Rouen with the greatest conrtesy, was quite unaware of any such discovery.
  3. "Another implement of the round pointed form has been discovered in Kent (Nov. 1861), on the surfaoe of the ground at the top of the hill on the east side of the Darent, about a mile E.S.E. of Horton Kirby, by Mr. Whitaker, F.G.S., of the Geological Survey."—(Evans' Archæologia, 1861, p 18.)
  4. Athenæum, July 16, 1859.
  5. Phil. Trans. 1860, p. 292.
  6. See also Sir E. Belcher, British Ass. T. 1860, p. 154, and Mr. Tyler's "Anahuac," p. 331.
  7. Nat. Hist. Review, Vol. 1, Pl. VII. figs 8 and 9.
  8. The bones of the stag owe their preservation perhaps to another cause. Prof Rütimeyer tells us that among the bones from the Pfahlbauten none are in better condition than those of the stag; this is the consequence, he says, "ihrem dichten Gefüge, ihrer Härte and Sprödigkeit, so wie der grossen Fettlosigkeit," peculiarities which recommended them so strongly to the men of the stone age, that they used them in preference to all others, nay almost exclusively, in the manufacture of those instruments which could be made of bone—(Fauna der Pfahlbauten, p. 12). How common the bones of the stag are in quaternary strata, geologists know, and we have here perhaps an explanation of the fact. The antler of this animal is also preferred at the present day by the Esquimaux in the manufacture of their stone weapons. (Sir E. Belcher, l.c. p. 154.)
  9. Phil. Trans. 1860.
  10. See Principles of Geology, p. 315.
  11. Proc. Roy. Soc. 1862.
  12. Proceedings, 1862.
  13. Buteux, 1. c, p. 98.
  14. D'Archiac, Progrés de la Géologie, p. 163.
  15. D'Archiac, l. c. p. 155.
  16. D'Archiac, l c. p. 164.
  17. D'Archiac, 1. c. p. 160.
  18. Malbos. Bull. Geol. Vol. III. p. 631.
  19. L. c., p. 163.
  20. Principles, 1853, p. 220.
  21. Proc. Roy. Soc. 1862, p. 44.
  22. Lyell, Principles, p. 77.
  23. Geol. Journal, 1853, p. 56.
  24. Geol. Jour., Vol. V. p. 4.
  25. Hopkins, l. c., p. 85.
  26. Mem. Soc. d'Em. l'Abbeville, 1861, p. 475.
  27. C. D'Orbigny, Bul. Geo. 2nd ser. V. xvii. p. 66.
  28. Proceed. Roy. Soc. 1862, p. 41.
  29. Cyc. Brit. Article "Rivers," p. 274.
  30. See Mr. Prestwich's paper read before the Royal Society, June 19th, 1862.
  31. While attributing the excavation of these valleys to the action of the existing rivers, Mr. Prestwich doubts whether they could have produced such an effect without an elevation of the land. Marine shells occur at Abbeville about 25 feet above the sea-level; this bed Mr. Prestwich correlates with some of the raised beaches round our coasts, and with the lower level valley gravels. The higher level valley gravels correspond in his opinion with the raised beaches which occur at a higher level.
  32. We shall probably ere long be able to divide this era into several divisions. Already we have two well marked epochs, the elephantine and the post-elephantine. But Prof. Worsaae proposes, and not without reason, to subdivide this latter into the period of the "Kjökkenmöddings" on the one hand, and that of the "Pfahlbauten" on the other. The contents of the Danish tumuli belonging to the Stone period, agree rather with those from the lake habitations of Switzerland, than with those which occur in the Refuse-heaps of Denmark, and though we could not expect to find many well-worked implements in the kjökkenmöddings, we ought otherwise surely to have obtained ere now at least some broken pieces of the beautiful flint weapons which were so common in Denmark during the later part of the stone period.
  33. "Such is the description of this little animal, called a Laplander; and it may be said, that, after the Monkey, he approaches nearest to Man."—Regnard's Journey to Lapland, p. 164.