the annual rings of Peuce Eiggensis and Peuce Lindleiana are as regularly and strongly marked as those of the Scotch fir or Swiss pine; nor, be it added, are they of larger size. In one specimen of our collection, but in one only, the rings average nearly a quarter of an inch in breadth; the tree added in a single twelvemonth almost half an inch to its diameter: but the specimen is an exceptional one. In the others they average from about a line to an eighth part; and in one specimen no fewer than twenty-eight rings occur in the space of an inch. The slow-growing tree, of which it formed a portion, sluggish in its progress as a Norwegian pine on some exposed mountain-side,-added only half an inch to its diameter in seven years. The unit here tells certainly of no rapid development of life, but, on the contrary, of a develop ment quite as tardy as that of the present age of the world in latitudes as high as our own; and, though we cannot decide with the same certainty respecting the rate of growth in the animals contemporary with those trees, we may surely most naturally infer that ostrea of some ten or twelve layers, or gryphites (extinct members of the same family) of some fifteen or twenty, could not have been very young; that as the ammonite, though thinly walled, was as solid in its substance as the nautilus, and had a great many more chambers, which were added to it piecemeal, one at a time, it could not have been of much quicker growth; and that, as the internal shell of the belemnite was much more ponderous than that of its successor the cuttle-fish, it must have attained to maturity quite as slowly. Further, not only can it be demonstrated that ivory teeth were every whit as dense in those ages as they are now,—a remark that applies equally to the later palæozoic periods,—but it can be shown also, that some of these teeth were as sorely worn as in existing animals when very old. In short, the evidence that life, animal and vegetable, existed on the farther side of the Tertiary geologic periods

under the same laws as now, is as conclusive as that it exists under the same laws on the farther side of the Atlantic. And these laws cast much light, as in the case of the peatmoss of our illustration, on the rate at which many of the mechanical deposits must have gone on. The Lias of Eathie,

for instance, consists, for about four hundred feet in vertical extent, of an almost impalpable shale, divided into layers scarce thicker than pasteboard. It might well be predicated, from the merely mechanical character of the deposit, that its formation could not have been rapid. But how greatly is the argument for the lapse of a vast period of time for its growth strengthened by the fact, that each one of these many thousand layers formed a crowded platform of animal life, and that so thickly are they covered with the remains of not only free shells, such as ammonites, but also of sedentary shells, such as ostrea, that the organisms of but two of the more crowded platforms could not find room on a single one! And these shells were the contemporaries of slow-growing pines, that on the average increased in diameter little more than the fifth of an inch yearly.

Nor, though we lack the regulating unit, is the evidence of the lapse of vast periods during the deposition of the paleozoic systems much less complete. The oldest wood that presents its structure to the microscope,-a fossil of the Lower Old Red Sandstone,-exhibits no annual rings; but it presents as dense a structure as the Norfolk Island pine. The huge araucarian of Granton has a structure nearly as dense. We have already incidentally referred to the solid ivory and much worn teeth of the reptile fishes of the Coal Measures. In the Mid-Lothian basin there are thirty seams of workable coal intercalated among deposits of various character, whose united thickness amounts to nearly three thousand feet, and under most of these seams the original soil may still be detected on which the plants that formed their coal flourished

and decayed.

Whole beds of the Mountain Limestone are composed almost exclusively of marine shells and the stems of lily encrinites. In the Old Red Sandstone there are three different formations abounding in fishes; and yet, so far as is yet known, there is not a single species of fish common to any two of them. And who shall tell us that the life-term of a creation is a brief period? In the Upper Silurian system we have examined a deposit more than fifty feet thick, every fragment of which had once been united to animal life, crustaceous, molluscan, or radiated. And how wonderfully, too, the farther geologists explore, and the more carefully they examine, are their formations found to expand! Phillips estimated the thickness of the Coal Measures at ten thousand feet. Sir Charles Lyell, in one of his recent visits to America, found that the Coal Measures of Nova Scotia had a thickness of more than fourteen thousand six hundred feet. Phillips estimated all the deposits beneath the Old Red Sandstone at twenty thousand feet. The geologists of the Government survey find that the Silurians alone amount to about thirty thousand feet; and under these, in Scotland at least, lie the clay-slates, the mica-schists, and the enormous deposits of the gneisses. On the Continent, the remains of whole creations have been found intercalated between what had been deemed contiguous systems. An entire system-the Permian-has been detected between the Coal Measures and the Trias; and that shell-deposit that extends between the Gironde and the Pyrenees, once regarded as of the same age with the Coraline Crag, has yielded seven hundred species of shells,—nearly twice the number of all the species found on the coasts of Britain, that belong neither to the Crag nor to the older Eocene. It is yet another creation that has appeared, for which fitting space must be found in the record. The more thoroughly the field-geologist examines, the larger become his demands on the eternity of the past for periods which it

is certainly very competent to supply. His sybil ever returns upon him; but, unlike her of old, it is with an increased, not a diminished store of volumes; and she ever demands for them a larger and yet larger price.

And why should the tale of years be refused her? Let year be heaped upon year, until the numerals that represent them, consisting all of nines, would extend in a close line from the sun to the planet Neptune, and they would still form but an inappreciable item in the lifetime of the Creator. We see nothing to regret in the truth, destined to become greatly more evident in the future than it is now, that there is nothing in all history, or in all creation, vast enough to be measured off against the periods of the geologist, save the spaces of the astronomer; or that, with relation to at least our own planet, rational existence is still in its immature infancy. Could we wish it to be otherwise? The world is still sowing its wild oats; and, though somewhat better, on the whole, than it has been, there is surely nothing in its present aspect to reconcile any one to the belief that it has attained to its ultimate development. Its present most prominent features, if we may so express ourselves, are the horrible sufferings of war and the lies of stock-jobbers.-October 25, 1854.

UNITY OF THE HUMAN RACES.*

THERE are certain typical forms of error that never die, though their details alter, and the facts and analogies on which they purport to be based vary with the increase of

* The Unity of the Human Races proved to be the Doctrine of Scripture, Reason, Science, &c. By the Rev. Thomas Smyth, D.D., Member of the American Association for the Advancement of Science.

knowledge and the progress of the human mind. And it is of great importance that these should be studied, not only in their essential, and, if we may so express ourselves, generic character, but also historically, in the various modifications of shape and colour which have marked them at their several periods of revival, and which will almost always be found to depend on some peculiarity of pursuit or opinion prevalent at the time, or, if connected with the physical sciences, on some newly-opened course of discovery. The various species of error once thoroughly mastered, the student will find ever after that it is with but its varieties he has to deal. Nay, by thoroughly knowing the species, and the history of the changes through which they passed at their several appearances, he may be able to anticipate the exact course which they would have to run should they re-appear in his own times, when men worse taught, and unacquainted with this cycloidal character of error, will neither know whence they come nor whither they are going. The native sagacity of the late Dr M'Crie was greatly sharpened by a knowledge of this kind, derived from his profound acquaintance with Church history; and he is said to have predicted, while Rowism was yet a howling enthusiasm, gibbering the untranslateable tongues, and stretching forth its hand to work miracles, that it was to end at no very remote period as a decrepit superstition. The fluttering butterfly was destined, agreeably to its previously determined constitution, to produce a brood of creeping caterpillars, though only the laborious student who had acquainted himself with its specific character, as exhibited in former manifestations, knew that such was to be the This perception of the specific essentials and consequents of both truth and error constitutes, too, at once the charm and the value of such a mastery over the controversies which have arisen within the Church, or in which, in selfdefence, the Church has been compelled to engage, as that

case.