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ments and fossil bones, and bids us re- that an ancient river or long lake flect that they at least could not have filled the broad valley of the Somme, been conveyed to where we see them if not after the entombing of the fosby any known force of water short of sil bones and the hatchets, at least that which it derives from the vehe- late in the period of the animals and ment internal heavings of the earth's men who owned them; and what crust. If the possibility is suggested more convincing monument could of their having been transferred hither such a sheet of fresh water have left by the floating power of ice, he directs behind it of its having existed during our regard triumphantly to the
bones an immense lapse of ages ? of Rhinoceros, Elephant, and Hippo- He of the Paroxysmist school, conpotamus, with which the boulders are templating the same phenomena, and associated, as testifying to probably some others, perhaps naturally overa warmer, certainly not a colder, looked by his friendly opponent, the climate than that now prevailing in advocate of slow mutations, is willing France, where no such process takes to concede the fresh water, and conseplace. He further asks our attention quently some important changes in to the obvious marks presented by the physical geography of the district these blocks, of their having been since those days, but he resolutely roughly bouldered in contact with dissents from the inference that the materials capable of extensively rub- sand must have required a very long bing down all their corners, edges, time to form, and insists on calling and original surfaces; and, ever ready our attention to three facts—first, for a skirmish in support of his ideas, that a portion of the sand is very he throws down the gage of battle by sharp and angular, indicating a rather demanding defiantly of the Quietist, transient movement; secondly, that by what processes of slow deposition, its lamination is by no means either erosion, and elevation, be proposes to level or uniform, but in many locali. explain not only these phenomena, ties is disturbed, undulating with but the fact that the deposit is spread the very undulating floor of gravel; broadcast over all the valley of the and, thirdly, that the trenches, holSomme, from beneath the peaty lows, and ridges in this floor or meadows which bound the river, up upper surface of the gravel, of themthe gently ascending slopes of this selves imply that the current which wide shallow trench in the land, to first passed across it, that of course the summits of the plateaus which which overspread it with the sand, determine the existing drainage, dis- was something far swifter than a tributed diffusedly, too, and not in quiet inflow of silting water-was, terraces, such as might denote oscilla- in truth, endowed with that far from tions in the relative levels of land trivial velocity which confers the
power of eroding and ploughing up When questioned as to the length of already settled or impacted subantime occupied in its formation by the gular matter, and of carrying part of next stratum-the bed of white and it bodily away. Perhaps he will add brown sand, from 7 to 10 feet thick, that the thickness of the sand is no lying immediately on the gravel - true measure of the time it has conthe advocate of gradual changes will sumed in forming, inasmuch as under respond, that assuredly here, at least, certain easily indicated favourable we witness the indications of a quiet conditions, of retardation of a current and greatly protracted period. He bearing floating particles, as great a will exclaim exultingly, Behold this depth of sediment will accumulate in very regular lamination, this firmness a few years, as would, under a normal and evenness, and, for a portion of state of things, consume many centhe bed, this water-worn smoothness turies in collecting: . We, self-constiof the granules; and take note espe- tuted umpires in this discussion, in. cially of the delicacy of these nume- terpose our conviction that neither of rous small, fragile, fresh-water shells, these earnest interpreters of nature identical in species with some of the is competent, in the present state of molluscs now inhabiting the region. science, to pronounce with any posiWhat stronger proof could be required tiveness whether the formative pro
cess was slow or rapid; for how slowly or mass of fresh water, commenced or how rapidly a given foot or fathom its formative functions at a higher of silted sand has taken to stratify level, or one nearer that of the itself, no geologist of either school plateau through which it now flows will venture soberly to calculate, es. -running on or over the upland, pecially when he reflects that neither and not below or within it, as it now school has hitherto succeeded in does—and that the drainage has attaining that familiarity with all the gradually excavated the valleys of modes of operation of that most mar- the Somme and its tributaries to vellous agent, water, without acquir- their present lower levels, collecting which, it is in vain to hope for a ing and strewing on their shifting quantitative measure of its rates of beds and banks the flint-gravel, with action, under apparently the most its embedded bones and human simple conditions.
relics. By assuming that this sinking Maintaining our station at the of the river-bed was continuous, and gravel-pits, with our two “represen- attended probably by a continuous tative men,” our Quietist and Parox- rising of the level of the land above ysmist interpreters of the geology, the sea, and was not accompanied by we tire at the prospect of receiv- any long pauses, or interrupted by ing somewhat similar explanations to counter-iovements of subsidence, we those just heard, if we venture to can account for the total absence of ask what time it took to form the traces of either sea - margins or two remaining beds in the bank-the river - terraces, and for the uniform narrow wildly-tossed layer of gravel, manner in which the gravel clothes and the faintly - laminated brown the eroded surface of the chalk, and sandy clay or brick-earth, which caps conforms to all its slopes. The the series, nourishes the grass, and cutting out or trenching of the shelters the Roman graves. We valleys is thus attributed to therefore terminate our interroga- fluviatile erosion, demanding an imtions by demanding of the cham- mense lapse of time for its accompion of each school his own ex- plishment, and not to an invasion or planation of the successive physical successive invasions of the sea, changes witnessed by this region of carving and modelling the land for the Somme since the period of the the reception and conveyance of the gigantic mammals, that we may, by atmospheric waters. The suggestion contrasting the two theoretical his- of an antiquity for the human family tories, the better appreciate what so remote as is here implied, in the Geology has at present to say in rela- length of ages required by the gentle tion to our leading inquiry—the pro- rivers and small streams of northbable antiquity of the primeval race eastern France to erode its whole of Men who left behind them the plain to the depths at which they now flint-implements of the Diluvium. flow, acquires, it must be confessed,
The Quietist, or student of nature's a fascinating grandeur, when, by more tranquil moods and changes, similitude of feature and geology, will probably offer something like we extend the hypothesis to the the following historic sketch. Start- whole north-west frontier of the ing with the formation of the gravel, continent, and assume, that from which contains the mammalian bones the estuary of the Seine to the and flint-implements, he will con- eastern shores of the Baltic, every ceive it to have been spread over external feature of valley, dale, and the surface of the chalk by a broad ravine-in short, the entire intaglio river subject to inundations, filling of the surface-has been moulded by the valley of the Somme, and sub- running waters, since the advent of merging the carcasses, or at least the the human race. bones, of the animals pasturing near Perhaps the geologist of the school its borders. To explain the wide dis- disposed to recognise only the more tribution laterally of the ossiferous gradual changes in the configuragravel, and its altitude above the tion of the surface, conscious of the present bed of the valley, it will be grave difficulties which beset the necessary to suppose that this river, present application of this hypothesis, will adopt a different explana- covers the chalk, and, what is especition, and set out with the conception ally puzzling, occur at all altitudes that the great valleys of the land upon the gently ascending sides of were already, scooped before the the valley, from its bed to the tablestrewing of the Diluvium or ossi- lands which bound it.
Here anferous gravel. His most natural other complex process of shifting assumption will then be, that the river sedimentation, with slow degravel was deposited in the bed pression or elevation of the land, and on the shores of a tidal estuary, must be resorted to, demanding a frequented by the makers of the flint lapse of time commensurate with, or hatchets and by the extinct quadru- even exceeding, that previously repeds, and that the stratum was dif- quired. Thus, proceeding through fused wider and higher by a progres- the thinner rudely eddied gravelsive sinking of the land, submerging bed which succeeds the river sand, successively fresh tracts, till all the and through the brick-earth, or ferrudistrict pow capped by this par- ginous sandy clay with splinters of ticular Diluvium was overspread. flint, which crowns the entire series, This supposition involves a much sustains the now existing life of the less protracted period than the pre- district, and entombs some of that ceding, not more time, indeed, than, which was of human mould almost at the rate of elevation or subsidence two thousand years ago, he will, with of the earth's crust at present in like ingenuity, establish the probaprogress on sundry coasts, would bility of two other enormous epochs, depress the district of the Somme making thus in all four vast revoluperhaps one hundred feet. Certain tions of the geologic index on this imindispensable evidence, of like na- measurable dial-plate, all between ture in both cases, is wanting to lend the embedding of the manipulated countenance to either of these hy- flints and extinct mammalians, and potheses. There are no independent the sepulture of the Roman occupants proofs, in the form of fluviatile shells, of the country. of the long residence of the rivers Let us now listen to the Paroxwithin their existing valleys at ysmist, who desires to measure the materially higher levels than those earth's rates of progress, not only they now occupy, to confirm the while she dallies with her tools, but former view; por any similar monu- when she puts forth her nearly resistments of the long residence of the less strength. By what agencies, and sea, or of estuary waters, in the shape in what relative time, does he conof marine organic remains in the bed ceive these four superficial strata may and on the lower slopes of the valley, have been produced ? to sustain the latter.
Till such are
Beginning, as before, with the grafound, both hypotheses may be re- vel-bed at the base of the series, be ceived as suggestive speculations, will allege that this can have occubut cannot be accepted as steps to- pied no very long period in its formawards a sound theory of the origin of tion:for, pointing to the sundry marks the flint-gravel of the Somme. of diluvial or turbulent aqueous action
Ascending to the beds wbich over- which it betrays, he will remind us lie this “sepulchral earth” of the that the motion of the strewing curmammoth and his associates, our rent must have been rapid, and that friend of the tranquil school will time is ever in the inverse ratio of account for them, by appealing to velocity. His notion of the order of processes very similar to those al- events will probably be something ready invoked. He will show us, like the following - Assuming the that the bed many feet thick of white pre-existing relief, or excavation raand brown sand, with the fragile ther, of the surface, to have approxifresh - water shells, testifies un mated to that now prevailing, he equivocally to some ancient river will account for the gravel by suplong and quietly resident above the posing a sudden rocking movement gravel. But these fresh-water sands of the land and the bottom of the sea cover the gravel almost as broadly of the nature of an earthquake, or a and continuously as the gravel succession of them, to have launch
ed a portion of the temporarily up- the rising grounds on both sides. To lifted waters upon the surface of explain how the sand has come to the land, the inundation penetrat- cover the gravel beyond the inmeing further inland, rising to high- diate borders of the valley, following er altitudes, and possessing more that stratum to the upper slopes and sweeping and destructive power, apparently even to the general tablealong the broad, gently-ascending, land of the country, he will ask us trumpet-mouthed valleys like the to note the fact, that while it is horiSeine and Somme, than on the unin- zontally and evenly laminated in the dented plain. To this inundation, less elevated localities, it displays in or more strictly to a series of such— those of a higher level, for instance for these vehement disturbances of at St Acheul, a lamination often the earth's crust usually repeat their much disturbed and oblique, and a visits to the same district many very irregular lower and upper bountimes in an epoch of commotion-he dary; features, all of which plainly will ascribe the ploughing up or intimate that it may have been swept washing up of the surface beds of sudilenly into these upper levels, by a the chalk, the sorting out, as it were, paroxysmal movement of the earth's and breaking, rolling, and rudely crust analogous to that which prestrewing of its embedded flint-no- ceded it, and produced the ossiferous dules, and the entombing of the huge gravel beneath. wallowing animals enticed by their In confirmation of this view, the instinctive wants to inhabit the tracts advocate of subterranean forces, as especially vulnerable to inundation, the primary agents in producing the Reflecting on the insufficiency of the superficial sediments, may point our evidence which would make man the attention to the conical pits or holcontemporary of the extinct Mam- lows in the surface of this bed of sand, moth, he will encounter no difficulty already alluded to, and appeal to in explaining how Man's remains may them in proof that a sheet of water have become buried at a long subse- in rapid and whirling motion must qnent epoch in the same Diluvium or have swept over the land about the Drift which had already received the close of its deposition, the prelude, bones of the colossal Elephant and it would seem, of the precipitation of his associates; for he will remind us the upper gravel-bed on that which that a second disturbance of the crust, covers the sand, if not the very cursimilar to that which had already en- rent itself which bore along the gratombed the quadrupeds, would, if ocvelly materials, and laid them where curring within historic time, find the they now repose. physical conditions even more suit- That this third stratum--the seable for an entombing inundation cond gravel-was thus deposited by than the first. The same valleys and a swift and eddying current, is so low plains would invite an invasion distinctly indicated, not merely by of the sea, only they would this time the feature now pointed out, but by be smoothed over with the ossiferous its irregular and oblique or diluvial gravel; and this bed for the waters lamination-if proper lamination it would be torn up, drifted, and depo- can indeed be said to possess-that sited afresh with whatsoever man the Paroxysmist is here confident may have left upon its surface, far that he beholds a record of only a more readily than was the well-jm- very brief period of time. pacted chalk by the previous great Reaching the fourth and upperinundation.
most bed of all—the brown ferrugi. Ascending to the next bed—the sili- nous sandy clay or brick-earth with cious sand with fresh-water shells, splinters of dispersed flint-the geothe Paroxysmist will account for this logist familiar with the signs of both by requesting us to imagine a broad gentle and violent watery action will river pouring its steady current over recognise the most quiet, and therethe bed of the valley, its waters fore the most time-representing sedicharged from time to time with more ment of the entire series. But even or less angular sand, washed out of in this material, the average thickthe adjacent gravel then constituting ness of which is between three and five feet, he will draw our attention recapitulation of the conclusions I to the abundance and occasional size have arrived at. of these fragments of flint, and may 1. To the question, Are the sodemand how they could have been called flint-implements of human introduced by water in very sluggish workmanship or the results of physimotion. He will probably abandon cal agencies ? My reply is, They bear some of his scepticism upon this point, unmistakably the indications of havhowever, if we request him to ob- ing been shaped by the skill of man. serve the almost total absence of 2. To the inquiry, Does the mere distinct lamination in the clay and association in the same deposit of the general fineness of its texture; the flint-implements and the bones the absence of lamination or internal of extinct quadrupeds prove that the stratification being one of his surest artificers of the flint-tools and the criteria of a perpendicular deposition, animals coexisted in time? I anit may be slowly or it may be rapidly, swer, That mere juxtaposition of in water either permanently or tran- itself is no evidence of contemposiently at rest; the slowness or rapid- raneity, and that upon the testiity of the precipitation, again, being mony of the fossil bones the age indicated mainly by the fineness or of the human relics is not proven. coarseness of the materials. So, 3. To the query, What is the looking at this uppermost deposit antiquity of the Mammalian bones of all, the minimum age of which is with which the flint-implements are proved to equal at least one-third of associated ? My answer is, That, the commonly imputed age of the apart from their mixture with the human race, by the presence within recently-discovered vestiges of an it of Gallo-Roman graves, and other early race of men, these fossils exremains historically identifiable, he hibit no independent marks by hesitates to acknowledge that even which we can relate them to human it can have occupied any prolonged time at all. The age of the Diluvium series of ages in its production. which embeds the remains of the ex
The physical conditions under tinct mammalian animals must now which it has been formed, he will not be viewed as doubly uncertainventure to speculate about, until so doubtful from the uncertainty of important a stratum, the floor of the its coincidence with the age of the now living creation, the outer cover- flint-implements—and again doubting of the tomb which enwraps the ful, if even this coincidence were bones and dust of all the organisms established, from the absence of any which once lived in the region and link of connection between those now live no more, shall have receiv- earliest traces of man and his hised a far more critical and widely toric ages. extended study than it has yet en- Upon the special question involved listed.
in this general query, What time Thus will the two translators of must it have required for the phythis last chapter in the Physical sical geography adapted to the PachyHistory of the Earth differ in their derms of the antediluvian period to reading of each successive page : the have altered into that now prevailone interpreting the record only by ing, suited to wholly different races: the gentler forces of existing nature, the geological world is divided beand inferring an enormous age for tween two schools of interpretation man, far transcending that deduced the Tranquillists, who recognise by the chronologists, while the other, chiefly Nature's gentler forces and adopting a quicker rate of forma- slower mutations, and the Paroxtion, confesses his uncertainty as to ysmists, who appeal to her violent whether these deposits originated subterranean energies and her more within the accepted period of human active surface-changes. history or not.
4. To the last interrogation, How Having discussed the leading far are we entitled to impute a high topics mentioned in my programme antiquity to these earliest physical as fully as explicitness demands, I records of mankind from the nature take leave of my reader with a brief of the containing and overlying se