LECT. V. region, in places where time has laid bare large perpendicular surfaces, are presented series of strata of different rock; and laminations of the same kind of rock, which amount to the thickness of one hundred feet, and two hundred, and still more. One of the laminated formations just mentioned may be said to furnish a chronometer for itself. It consists of sixty feet of siliceous and calcareous deposits, each as thin as pasteboard, and bearing upon their separating surfaces the stems and seed-vessels of small water-plants in infinite numbers; and countless multitudes of minute shells, resembling some species of our common snail-shells. These layers have been formed with evident regularity, and to

lava first flowed into the valley. In another spot, a bed of basalt, 160 feet high, has been cut through by a mountain-stream.- -The vast excavations effected by the erosive power of currents along the valleys which feed the Ardèche, since their invasion by lava-currents, prove that even the most recent of these volcanic eruptions belong to an era incalculably remote." Mr. Poulett Scrope's Memoir of the Geology of Central France.

"The time that must be allowed for the production of effects of this magnitude, by causes evidently so slow in their operation, is indeed immense but surely it would be absurd to urge this as an argument against the adoption of an explanation so unavoidably forced upon us. The periods which, to our narrow apprehension and compared with our ephemeral existence, appear of incalculable duration, are in all probability but trifles in the calendar of nature. It is Geology that, above all other sciences, makes us acquainted with the important, though humiliating fact. Every step we take in it forces us to make unlimited drafts on antiquity.

"There are many minds that would not for an instant doubt the God of nature to have existed from all eternity, and would yet reject as preposterous the idea of going back a million of years in the history of his works. Yet, what is a million, or a million million, of solar revolutions, to an ETERNITY?" Ib. p. 165.

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each of them we may reasonably assign the term _LECT. V. of one season, that is a year. Now thirty of such layers frequently do not exceed one inch in thickness. Let us average them at twenty-five. The thickness of the stratum is at least sixty feet; and thus we gain, for the whole of this formation alone, eighteen thousand years.

Further: many of these hills in the form of sugar-loaves consist of, or are coated with, pumice-stone and other loose and light substances, which every person knows to be volcanic products. It is self-evident that these could not have withstood the action of a flood: they must have been broken down and washed away with the first rush of water. Either, then, the eruptions which produced them, took place since the deluge; or that deluge did not reach to this part of the earth. Against the former side of this alternative the argument from analogy is very strong. All that we know of the history of volcanoes impresses us with the vast improbability, that such an intensity and extent of volcanic action as belonged to the later series only of these eruptions, could begin, run their course, and come to an end by settling in perfect quiescence, within the period from the deluge to our first historical notices of this district, which is about 2300 years. Supposing the eruptions in question to have commenced immediately upon the subsiding of the diluvial waters, it would be contrary to all known instances of volcanic action, to

LECT. V. Suppose that they would finally cease within a less period than many centuries. Now Julius Cæsar, in his Gallic wars, was encamped in this very district, at the closing part of the period just mentioned. His writings furnish abundant evidence of his observant, inquisitive, and acute character. Notwithstanding his vicious habits, he had a mind deeply imbued with literature, and the love of philosophical pursuits; and he made considerable attainments in science so far as in his day was practicable. Had he found in this place any tradition of volcanic action as having formerly existed, it is morally certain that his curiosity would have been powerfully awakened, and that we should have had in his Commentaries the result of his inquiries. But nothing of the kind exists, though he indicates his acquaintance with the features of the country, as having surveyed it with the eye of a general.*

Other objec

tions to the

of the deluge.

The geological difficulties are not the only universality ones which present themselves, in relation to the admission of a strictly universal deluge, and some of the circumstances which are commonly supposed to be affirmed or implied in the sacred narrative. It would be a failure in the service which I have undertaken, were I to pass these by without notice: but I must renew my entreaty that my auditors would not permit any

*Comment. vii. 4, 9, 36.

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conclusion unfavourable to the perfect verity of LECT. V. the Mosaic narrative, correctly interpreted, to

lodge in their minds; for I trust that, in a future lecture, satisfactory proof will be brought that such conclusion would be erroneous.

water.

The mass of water necessary to cover the Quantity of whole globe to the depth supposed, would be in thickness about five miles above the previous sea-level. This quantity of water might be fairly calculated as amounting to eight times that of the seas and oceans of the globe, in addition to the quantity already existing. The questions then arise, Whence was this water derived; and how was it disposed of, after its purpose was answered? These questions may indeed be met, by saying that the water was created for the purpose, and then annihilated.That Omnipotence could effect such a work, none can doubt: but we are not at liberty thus to invent miracles, and the narrative in the Book of Genesis plainly assigns two natural causes for the production of the diluvial water; the incessant rain of nearly six weeks, called in the Hebrew phrase the "windows of heaven," that is, of the sky; and the "breaking up of all the fountains of the great deep." By the latter phrase some have understood that there are immense reservoirs of water in the interior of the earth, or that even the whole of that interior, down to the centre, is a cavity filled with water; a notion which was excusable in the defective state of knowledge

LECT. V. a century ago, but which, from the amplest evidence, we now know to be an impossibility. The use of this expression, in other parts of Scripture, sufficiently proves that it denotes the general collection of oceanic waters. It is scarcely needful to say, that all the rain which ever descends, has been previously raised, by evaporation, from the land and water that form the surface of the earth. The capacity of the atmosphere to absorb and sustain water is limited. Long before it reaches the point of saturation, change of temperature and electrical agency must produce copious descents of rain: from all the surface below, evaporation is still going on: and, were we to imagine the air to be first saturated to the utmost extent of its capacity, and then to discharge the whole quantity at once upon the earth, that whole quantity would bear a very inconsiderable proportion to the entire surface of the globe. A few inches of depth would be its utmost amount.* It is indeed the fact that upon a small area of the earth's surface, yet the most extensive that comes within experience or natural possibility, heavy and continued rain for a few days often produces effects fearfully destructive, by swelling the streams and rivers of that district: but the laws of nature, as to evaporation and the capacity of atmospheric air to hold water in solution, render such a state of things over the

* Seven inches, according to Mr. Rhind, in his Age of the Earth, p. 100, Edinb. 1839.