The course of creation

by John Anderson

And so it has been with the whole Course of Creation—the succession of strata, of animal and vegetable tribes, and with man and the adaptive provision for his higher destiny. This is a doctrine of development and of progression, widely different from that of the “Vestiges,” more in unison with the Creator’s wisdom and the Creator’s care:—a speculation worthy of a separate treatise, namely, the progress and development of man’s intelligent, moral, and spiritual being as indicated in the course of revelation.

CHAPTER IV.
CAUSES OF EXTINCTION OF ORGANIC LIFE.

When the palæontologist has completely established his position, that all the organic phenomena of primeval times have resulted from the impress of original structure, in opposition to the theory of progressive development and transmutation of species; and when he can trace, also, corresponding changes in the mineral formations in which the fossil remains are imbedded, the important inquiry has still to be made into the causes of the extinction of so many races of the animal and vegetable kingdoms. Introduced successively upon the surface of the earth, was there always a physical and necessary relation betwixt the living tribes and the varying conditions of the surrounding media in which their lot was cast? And do the differences in the one explain the changes in the organic functions of the other?

When we look back to the earliest of the fossiliferous rocks we can discover something in the nature of their materials themselves which would cause the destruction of their organic tribes. The Silurian strata have been violently disturbed, and much molten matter, during the period of their deposition, injected among them; and by causes such as these, life would suffer greatly, and whole races be suddenly destroyed. Even the strong incased ganoids and placoids of the Devonian period could not always be able to subsist and bear up against the spasmodic throes that produced the conglomerates. Animals preyed likewise upon each other, and by this means kept up then, as now, the general average and balance of life. But in none of these modes can anything like a law be inferred, any stated provision be detected, for the outgoing and the incoming of the different genera and species which successively peopled the globe. The rocks differ, as the organisms differ, age to age, from each other: but the series of changes traced in the one class of phenomena, furnish only a few data by which to determine as to the alterations that would be produced in the class cotemporaneous.

No land animals have been found in any of the formations beneath the new red sandstone. No quadrupeds existed before the tertiary age. And the monster lizards which so exuberantly sprang into existence during the middle secondary epoch, had all disappeared when these terrestrials occupied the stage. Wisdom we can trace in all the arrangements; care and goodness are everywhere apparent. The seas swarmed with marine animals, while the terrestrials could scarcely have subsisted on an upheaving earth and new forming land. Quadrupeds roamed not over fields so diversified by the lakes and slimy lagoons in which the Saurians found their convenient habitation. And beyond the simple fact, that Divine will so ordained that such things should be, both in the animal and mineral changes in the history of our planet, we have only a ray of light to guide us in interpreting the revolutions and destructions which are therein so indelibly recorded.

The mollusca and shell families appear and depart along with the calcareous deposits which inclose their remains; but we know as much of the source of the one as of the range and limit of, or the causes which destroyed, the other. Orthoceræ and nautili have survived all changes, and have maintained in the types by which they are represented their old instincts and predaceous propensities. The holoptychii and dipteri perished, just as the materials of the new red sandstone were being deposited, and whose identity, in all essential mineral qualities, differs in nothing from the old red in which they are entombed. The flora of the carboniferous age came and went with the suddenness and entireness of an eastern dynasty, the gorgeous spoils of which are all that remain to attest its former greatness. The mammoths, dinotheriums, and kindred pachyderms of the tertiary groups had all left the earth on the dawn of the human epoch. And now, since the commencement of that epoch, we find that entire families have become extirpated, that species of others have been driven from their former localities, and that generally, both of vegetables and animals, the geographical distribution is being, year by year, greatly modified. During the last century, the introduction into Germany of some new species of insects, and their multiplication, utterly destroyed forests of vast extent; and every year, in some quarter of the globe, we hear of equally mighty catastrophes produced by equally minute insidious causes.

The organic things of earth, it would thus appear, have their terms of existence of longer and shorter duration, and the race at last dies out equally with the individuals which compose it. No better reason for this can be assigned, than that such is, and has always been, the course of nature. Particular families of plants and animals are cotemporaneous with particular groups of rocks: with these they are observed for the first time; at the close of the deposit, all farther traces of their remains are lost; and, in so far, there is ground for arguing that the same general causes were concerned in effecting the successive changes, organic as well as inorganic, of the periods and formations in question. What these causes were, it may never be permitted to science fully to determine. It was indeed, the opinion of Cuvier, that in the mammoth epoch a change of climate effected the destruction of this giant family of pachyderms. This change of climate has been accounted for by Murchison and others, especially in Siberia, where so many remains are found, by an elevation of the country to the height of one or two hundred-feet above its former level. And doubtless, by such a change, animal as well as vegetable life must, in many specific forms, have been greatly affected.

There can be little doubt, however, of the most perfect adaptive arrangements prevailing through all the geological epochs, some of which have been plausibly conjectured. As reptiles, for instance, differ from birds and mammals, in having a lower and simpler structure of the lungs and heart, and therefore a less active performance of the respiratory functions, they become less dependent on the atmosphere or oxygen for existence. “Hence,” says Professor Owen, “from their extraordinary prevalence in the secondary periods, under varied modifications of size and structure, severally adapting them to the performance of those tasks in the economy of organic nature which are now assigned to the warm-blooded and quick-breathing classes, the physiologist is led to conjecture that the atmosphere had not undergone those changes, which the consolidation and concentration of certain of its elements in subsequent additions to the earth’s crust may have occasioned during the long lapse of ages during which the extinction of so large a proportion of the reptilian class took place. And if the chemist, by wide and extended views of his science in relation to geology, and mineralogy, should demonstrate, as the botanist from considerations of the peculiar features of the extinct flora has been led to suspect, that the atmosphere of this globe formerly contained more carbon and less oxygen than at present, then the anatomist might, à priori, have concluded that the highest classes of animals suited to the respiration of such a medium must have been the cold-blooded fishes and reptiles. And beside, the probability of such a condition of the zoological series being connected with the chemical modifications of the air, the terrestrial reptiles, from the inferior energy of their muscular contractions, and still more from the greater irritability of the fibers and power of continuing their actions, would constitute the highest organized species, best adapted to exist under greater atmospheric pressure than operates on the surface of the earth at the present time.”

By parity of reasoning it may be inferred, that as great changes would be effected in the waters of the globe as in the constituents of the atmosphere; and, while thus preparing for the introduction of new families of animals, the destruction of already existing tribes may be as conclusively imagined. The various calcareous deposits in the mountain limestone, magnesian, oolite, and chalk periods, would imply very different qualities in the condition of the ocean; an infusion or abstraction of ingredients as favorable to the existence of one kind of animal life as they would be destructive of another. A period of great plutonic action, too, when vast masses of melted matter, charged with metallic and other substances, were poured over the bed of the sea, could not fail to have considerable influence upon many of the inhabitants of the deep; and while providence was making arrangements for an increase, or diversity, or for higher types of animal life, the existence of other forms and classes was ordained to terminate.