One established principle of the science connected with this point is, that there are certain groups of animal species found fossil in the different sets of strata which compose the earth’s crust, and that these demonstrate something like a series of distinct faunas corresponding to the number of formations. Seven or eight sets of rocks, at least, are as distinctly characterized by particular sets of fossils. But the exceptions to the law are likewise very numerous, inasmuch as both species and genera have been carried forward, and are identically the same, from one formation and epoch into another. Hence, points neither of difference nor of resemblance, from age to age, are absolute, and cannot very minutely be applied as regards the several formations and their organic contents. The types of one formation are repeatedly mingled with those of another. And the value of all the evidence collected from fossil remains, while it establishes undeniably a succession in the mineral deposits, leaves the question as to the limits of the epochs, and their relation to Time, still partially undetermined. The theory too of progressive development, or that of independent acts of creation—the causes of the extinction of old, and the introduction of new races—the extent of time implied or indicated in the whole series of events—and the all-important point involved in this chronology, whether all or any of the geological series are alluded to in the Mosaic account of creation—are questions that necessarily press upon the attention, as we would solve or not the inquiries suggested. The sounding-line of geology is not to be despised, or cast at once aside, should it fail in furnishing a just estimate and measure of such profound investigations. Every failure will only prove a stimulus to renewed exertion, as every discovered path of error leads one step in advance toward the path of truth, and that in turn to harmony with the Book of all truth.
CHAPTER II.
THEORIES OF ORGANIC LIFE.
After inquiring into their order of succession, the relation which organic fossils have to each other, as genera and species, falls naturally to be considered. How have these various families of creatures, brought to light by geology, been formed? In what manner have they become extinct? Have they all proceeded from a few original types, which have been modified by circumstances, increased in variety, and perfected in form, as they advance from the older to the newer formations? And does geology furnish any data on which to build a theory of their extinction as the higher and succeeding kinds emerged into being? A learned author, Professor Pictet of Geneva, has spoken of these speculations in terms of a rule or law, as follows:—“The faunas of the most ancient formations are made up of the less perfectly organized animals, and the degree of perfection increases as we approach the more recent epochs.”
This was long held as a favorite dogma among geologists, when, in proportion to the scantiness of facts, there was an increasing eagerness to magnify their value, and to build upon them the widest generalizations. But now, since accurate observations are more and more multiplied, and the principles of palæontology are better understood, the doctrine of a gradual advance of animal organization toward higher and more perfect forms as we ascend through the successive deposits of the earth’s crust, is daily losing ground among the cultivators of the science. The notion is based upon the theory of a scale of beings, in which all animals are supposed to form a series, or to constitute links of an unbroken chain, whereof each species is more perfect than that which precedes it, and the varying degrees of perfection constantly increasing until they reach their maximum in man, the highest link in the chain. M. Pictet himself regards this theory as vague and unsupported by facts, as well in the organization of the extinct as of the existing races of animals. These beings, he says, are divided into a certain number of groups, each of which exhibits a peculiar type; but while some of the groups are manifestly superior to others when we consider their organization generally, it happens also that the result of a comparison sometimes fails to establish any real superiority. The faunas of the more ancient formations he holds to be far less imperfect than has been often supposed, where the vertebrate type is represented by the fishes, and whose structure is as complicated and finished as the most recent of their kind; while the invertebrate again furnishes numerous examples of fossilized gasteropoda and cephalopoda, the most perfect orders of the molluscous class. As with these, so with the relics of every succeeding epoch, in which all the types, the genera, and species of every family of the animal kingdom, are represented by organic structures as perfect as those of the present day.
We quote the following important cautionary remark by the same author:—“We ought not,” says Professor Pictet, “to be too hasty in assuming the absence of certain more perfect types in the older faunas, merely because we have not yet discovered any remains of them. We hardly know anything of these faunas, except with regard to some of the inhabitants of the sea; and it is well known, that in the present condition of the globe, those animals living on land exhibit the higher forms of structure. Is it not possible that in these first ages of the world, terrestrial animals also existed, more highly organized than their marine cotemporaries, although their remains either have not been preserved, or are still to be discovered? The existence of didelphine mammals in the oolites has been made out by the discovery of a very small number of fragments; and the remains of land animals generally are hardly fossilized, except by sudden deluges and inundations, which are always trifling in their results, compared with the slow but unceasing deposits from the water of the sea. May we not yet expect new discoveries in these ancient strata, revealing to us the existence of primeval animals at present little suspected?”
The same mode of reasoning may be extended to the ancient floras, or terrestrial plants of the primeval ages. What a revelation, for instance, is made in the recently discovered coal deposits of Oporto and the Upper Douro, where, along with the orthides, trilobites, and graptolites of the lower silurian rocks, are found vegetable impressions strongly resembling the ferns of the carboniferous age? The Cromarty fossil pine, from the lower old red sandstone, has been already noticed. While these pages have been passing through the press we have to record the discovery of a specimen, nearly two feet in length and half a foot in thickness, from the beds of the middle old red and immediately underlying the yellow sandstone of Dura Den. This fossil is considerably flattened and furred with the scars or markings so characteristic of the decorticated trees belonging to the coal formation. Does not this warrant the expectation of a richer harvest to be yet gleaned in these ancient fields than the marine fuci and algæ that have hitherto been mainly gathered in by the geological sickle?
Another mode of accounting for the succession of organized beings on the surface of the globe, and consequently also their successive extinction and outgoing, as seen in the fossiliferous rocks, is that which is termed the theory of development, or the doctrine of the transmutation of species. The same has been a very ancient and favorite notion among mankind. Early in this century it assumed the form of a system, under the adaptive principle of Lamarck, who conceived that animals, according to the circumstances in which they are placed, by the use or disuse of certain organs, the frequency and degree of exertion or strain upon particular parts of the body, were themselves the agents in inducing all the variety of structures by which they are distinguished into so many orders and families. The aquatic fowl, for example, is attracted to the waters in quest of food, and so in time becomes web-footed. The heron dislikes to plunge into the flood, or will only venture into the shoals, and hence he becomes a wader, and is equipped with long legs. The woodpecker rejoices in those little aphides and creatures that nestle under the bark of trees, and thus, from constant exercise, acquires his strength of bill. The eagle seeks the blaze of the sun, and soars to the gates of heaven, and hence his penetrating eye and speed of descent upon his all-unconscious victim beneath. And, in like manner, through the whole range of animated nature, and in all past ages, genera and species have all acquired their adaptive powers, and distinctive forms of organization, arising from a certain plastic character in their different constitutions, and their own voluntary attempts to supply their constantly increasing wants. There were a few great leading stamps or dies of nature’s own molding; but all the rest—even man himself—are merely offsets from the primitive type, with such extension of organs and modification of excrescences as were required in each particular case; succeeding races always retaining a strong affinity to their immediate predecessors, and a tendency to impress their own features on their kindred which succeed them. There is a limit of divergence; but within that limit, the human family have their place assigned them among the monkeys and wild men of the woods.
It is the same extravagant idea, that of a constant progression toward animal perfection, which has become so popularized in “The Vestiges of the Natural History of Creation.” This author, indeed, has taken a wider and bolder flight than even the French philosopher, M. Lamarck. He brings the rudimentary elements and molecular forms of all creation before him. He expatiates through infinite space, and amidst the original fire-mist of the astral worlds. He finds but one grand law pervading the whole universe of being, operating in the self-same way in the production of planets and suns, as in the germination of insects and animalcules, the life-impregnating principle in the one being only a modification of the aggregating and rotary tendencies that rule in the other—the blind and casual evolution of some agency of a material system, substituted for the creative will of an intelligent ever-active First Cause. “A nucleated vesicle” is the fundamental form of all organization, as nuclei of luminous matter are the sources of the stars; this is the meeting point between the organic and the inorganic, the end of the mineral and beginning of the vegetable and animal kingdoms; whence they start in different directions, but in a general parallelism and analogy. Assuming the vast indefinite periods of the geological epochs to be correct, the author makes great account of time, and the mighty changes which will be produced in the lapse of countless ages, and thus rebuts the argument against his theory that is so obviously furnished from the fixed unaltered characters of organization that have prevailed throughout the entire modern epoch. This he argues is merely a point, an infinitesimal fraction, when compared with the epochs of geology. The eye detects not the changes which all specific forms are slowly but unceasingly undergoing within limited portions of time, even as the nicest instruments cannot always enable the astronomer to note the changes of position among the heavenly bodies. Hence the appearance of so many of the stars as unchangingly fixed in their relations to each other. The whole solar system, too, upon the ground of imperfect unrecording vision, seems to be anchored in one portion of space. And hence likewise the argument against the motion of the earth itself, which so long prevailed, derived from the fact of there being no sensible parallax, and now so easily accounted for by the insignificant smallness of its orbit, as compared with the remoteness of the stars. Limited, in like manner, to the narrow field of observation afforded within the human period, the modifications of species and their transmutations into the higher grades of animals are not appreciable, because its six thousand years are as a moment, in comparison with those incalculable ages of geology which have been concerned in the phenomenon!
Thus does the author of the “Vestiges” revel amidst the sublimities and copious materials of his subject. Time and space, the elements of the astral heavens and the earth, are alike indefinitely in his grasp. That he has failed to frame a better system of things than the one we see actually around us, is a necessary consequence of the restraints imposed on human investigation. Facts will not be supplanted by any heights, or depths, or ingenuities of speculation. And as existing nature is all against the doctrine of transmutation and development, so the discoveries of geology through all its formations are equally opposed to such views of creation. A short sketch of both will abundantly illustrate this.