his day, or he may have begun to be in theirs; and the bare juxtaposition of their remains in a geological formation can not tell us which.

Professor Rogers is very explicit to the same effect:

"Let us admit that the wrought flints are truly contemporaneous with the animals whose bones lie side by side with them, and that the deposit imbedding both is the general Diluvium or mammalian drift, do these facts determine the flints to have been fashioned in an age preceding the usually assigned date of the birth of man? Logically, it must be conceded they do not; for, independent of the absence or presence of these or other vestiges of man in the Diluvium, its antiquity, or relation to historic time, is obviously not ascertainable. Apart from human relics in, or over, or under the drift, how can we link it on to historic time at all? Before the flint implements were found in this superficial formation, or so long as the traces of man were known only in deposits later than the Diluvium, it was deemed to belong to an age antecedent to the creation of man, and had, therefore, a relatively high antiquity assigned to it; but now, granting that the relics of man have been authenticated as buried in it, is it sound reasoning, we would ask, to infer for these relics the very antiquity which was only attributable to the Diluvium because it was believed destitute of all such human vestiges? The Diluvium of the geologists has, since the illustrious Cuvier, been always looked upon as

something very ancient, simply because he and his successors, finding it replete with the remains of huge land mammals no longer living, never succeeded in detecting in it a solitary bone or tooth of any human being, nor indeed of anything indicative of man's existence; but now that things indicative of man have been found, it is surely illogical, and a begging of the very question itself, to impute an age incompatible with his then existing.

"As matters now stand, is it not as natural to infer the relative recency of the extinct Elephas Primogenius, and the other mammals of the Diluvium, from the co-existence of the works of man with them, on the ground that the human is the living and the modern race, as it is to deduce the antiquity of man from the once erroneously assumed greater age of those animals? I would repeat, then, that a specially remote age is not attributable to the flint-carrying men of the Diluvium, simply because it is the Diluvium or the mammoth-imbedding gravel which contains them. If the association with these extinct animals does intimate a long pre-historic antiquity, the evidences of this are to be sought in some of the other attendant phenomena.” *

We come, then, to the second argument derived from these alleged "attendant phenomena," viz., the geological changes recorded in the features of the Somme valley, and the immense periods of time which they must have required.

* Blackwood's Mag., Oct., 1860, pp. 428-431.

The most recent fact is the deposit of the peat-bed in the bottom of the valley. (See the diagram, p. 301.) "Careful observations," says Sir Charles Lyell, "have not been made with a view of calculating the minimum of time which the accumulation of so dense a mass of vegetable matter must have taken. A foot in thickness of highly compressed peat, such as is sometimes reached in the bottom of the bogs, is obviously the equivalent in time of a much greater thickness of peat of spongy and loose texture, found near the surface. The workmen who cut peat, or dredge it up from the bottom of swamps and ponds, declare that, in the course of their lives, none of the hollows which they have found, or caused by extracting peat, have ever been refilled, even to a small extent. They deny, therefore, that the peat grows. This, as M. Boucher de Perthes observes, is a mistake; but it implies that the increase in one generation is not very appreciable by the unscientific.

"The antiquary finds near the surface GalloRoman remains, and, still deeper, Celtic weapons of the stone period. But the depth at which Roman works of art occur varies in different places, and is no sure test of age, because in some parts of the swamps, especially near the river, the peat is often so fluid that heavy substances may sink through it,

carried down by their own gravity. In one case, however, M. Boucher de Perthes observed several large flat dishes of Roman pottery lying in a horizontal position in the peat, the shape of which must have prevented them from sinking or penetrating through the underlying peat. Allowing about fourteen centuries for the growth of the superincumbent vegetable matter, he calculated that the thickness gained in a hundred years would be no more than three French centimetres (1.17 inches). This rate of increase would demand many tens of thousands of years (30,000) for the formation of the entire thickness of thirty feet."- Geolog. Evid., pp. 110,

III.

But the formation of the peat could not have commenced till after the process of excavating the valley was completed. The gravel bed, next above it, was carried away, leaving only the small portions, 3, 3. (See diagram.) Previous to this was the formation of that bed; still further back, the denudation of the upper gravel bed, 4, and the wearing away of the rock eighty feet or more between it and 3; and lastly, the formation of the upper bed with its inclosed bones and flint implements a series of events involving an ascending scale of time into the past, the lower step of which was not less than 30,000 years, and each higher one possibly still

longer. "No one," says the writer before quoted (p. 306), "who gives to these considerations their due weight, can hesitate in admitting that they carry back the origin of man into that dim remoteness in which all account of time is lost.” *

It is to be observed, that this computation assumes that the only agencies which have been concerned in producing the phenomena of this valley, are those that now exist, both in kind and degree of activity. Sir Charles Lyell, and those who agree with him in his views on this subject, are, in geological parlance, Uniformitarians; † and his reasonings throughout, whether having relation to the filling of river deltas, the growth of peat, the denudation of valleys, and the like, are all based upon this assumption as a first principle of geological science.

* Westm. Rev., April, 1863, p. 281.

† Professor Rogers describes the two schools of geologists thus: "The Uniformitarian School, or, as sometimes designated, Quietists, who, interpreting the past changes in the earth's surface by the natural forces, especially the gentler ones, now in operation, overlook the more energetic and promptly acting ones; the other, the School of the Catastrophists, perhaps more fitly termed the Paroxysmists, who, blind in the opposite eye, see only the most vehement energies of nature, the earthquake and the inundation, and take no account of the softer but unceasingly efficient agencies which gradually depress and lift the land, or silently erode and reconstruct it."- Blackw. Mag., Oct., 1860, p. 432.