Part 6

The history and constitution of the world have now been hypothetically explained, according to the best lights which a humble individual has found within the reach of his perceptive and reasoning faculties.

We have seen a system in which all is regularity and order, and all flows from, and is obedient to, a divine code of laws of unbending operation. We are to understand from what has been laid before us that man, with his varied mental powers and impulses, is a natural problem of which the elements can be taken cognisance of by science, and that all the secular destinies of our race, from generation to generation, are but evolutions of a law statuted and sustained in action by an all-wise Deity.

There may be a faith derived from this view of Nature sufficient to sustain us under all sense of the imperfect happiness, the calamities, the woes and pains of this sphere of being. For let us but fully and truly consider what a system is here laid open to view and we cannot well doubt that we are in the hands of One who is both able and willing to do us the most entire justice. Surely, in such a faith we may well rest at ease, even though life should have been to us but a protracted malady. Thinking of all the contingencies of this world as to be in time melted into or lost in some greater system, to which the present is only subsidiary, let us wait the end with patience and be of good cheer.

GEORGES CUVIER

The Surface of the Globe

Georges Cuvier was born Aug. 24, 1769, at Montbéliard, France. He had a brilliant academic career at Stuttgart Academy, and in 1795, at the age of twenty-six, he was appointed assistant professor of comparative anatomy at the Museum d'Histoire Naturelle in Paris, and was elected a member of the National Institute. From this date onwards to his death in 1832, his scientific industry was remarkable. Both as zoologist and palæontologist he must be regarded as one of the greatest pioneers of science. He filled many important scientific posts, including the chair of Natural History in the Collège de France, and a professorship at the Jardin des Plantes. In 1808 he was made member of the Council of the Imperial University; and in 1814, President of the Council of Public Instruction. In 1826 he was made grand officer of the Legion of Honour, and five years later was made a peer of France. The "Discours sur les Révolutions de la Surface du Globe," published in 1825, is essentially a preliminary discourse to the author's celebrated work, "Recherches sur les Ossemens fossiles de Quadrupèdes." It is an endeavour to trace the relationship between the changes which have taken place on the surface of the globe and the changes which have taken place in its animal inhabitants, with especial reference to the evidence afforded by fossil remains of quadrupeds. "It is apparent," Cuvier writes, "that the bones of quadrupeds conduct us, by various reasonings, to more precise results than any other relics of organised bodies." The two books together may be considered the first really scientific palæontology.

I.--Effects of Geological Change

My first object will be to show how the fossil remains of the terrestrial animals are connected with the theory of the earth. I shall afterwards explain the principles by which fossil bones may be identified. I shall give a rapid sketch of new species discovered by the application of these principles. I shall then show how far these varieties may extend, owing to the influence of the climate and domestication. I shall then conceive myself justified in concluding that the more considerable differences which I have discovered are the results of very important catastrophes. Afterwards I shall explain the peculiar influence which my researches should exercise on the received opinions concerning the revolutions of the globe. Finally, I shall examine how far the civil and religious history of nations accords with the results of observation on the physical history of the earth.

When we traverse those fertile plains, where tranquil waters cherish, as they flow, an abundant vegetation, and where the soil, trod by a numerous people, adorned with flourishing villages, rich cities, and superb monuments, is never disturbed save by the ravages of war, or the oppression of power, we can hardly believe that Nature has also had her internal commotions. But our opinions change when we dig into this apparently peaceful soil, or ascend its neighboring hills. The lowest and most level soils are composed of horizontal strata, and all contain marine productions to an innumerable extent. The hills to a very considerable height are composed of similar strata and similar productions. The shells are sometimes so numerous as to form the entire mass of the soil, and all quarters of the globe exhibit the same phenomenon.

The time is past when ignorance could maintain that these remains of organised bodies resulted from the caprice of Nature, and were productions formed in the bosom of the earth by its generative powers; for a scrupulous comparison of the remains shows not the slightest difference between the fossil shells and those that are now found in the ocean. It is clear, then, that they inhabited the sea, and that they were deposited by the sea in the places where they are now found; and it follows, too, that the sea rested in these places long enough to form regular, dense, vast deposits of aquatic animals.

The bed of the sea, accordingly, must have undergone some change either in extent or situation.

Further, we find under the horizontal strata, inclined strata. Thus the sea, previously to the formation of the horizontal strata, must have formed others, which have been broken, inclined, and overturned by some unknown causes.

More than this, we find that the fossils vary with the depth of the strata, and that the fossils of the deeper and more ancient strata exhibit a formation proper to themselves; and we find in some of the strata, too, remains of terrestrial life.

The evidence is thus plain that the animal life in the sea has varied, and that parts of the earth's surface have been alternately dry land and ocean. The very soil, which terrestrial animals at present inhabit has a history of previous animal life, and then submersion under the sea.

The reiterated irruptions and retreats of the sea have not all been gradual, but, on the contrary, they have been produced by sudden catastrophes. The last catastrophe, which inundated and again left dry our present continents, left in the northern countries the carcasses of large quadrupeds, which were frozen, and which are preserved even to the present day, with their skin, hair and flesh. Had they not been frozen the moment they were killed, they must have putrefied; and, on the other hand, the intense frost could not have been the ordinary climatic condition, for they could not have existed at such low temperatures. In the same instant, then, in which these animals perished the climate which they inhabited must have undergone a complete revolution.

The ruptures, the inclinations, the overturnings of the more ancient strata, likewise point to sudden and violent changes.

Animal life, then, has been frequently disturbed on this earth by terrific catastrophes. Living beings innumerable have perished. The inhabitants of the dry land have been engulfed by deluges; and the tenants of the water, deserted by their element, have been left to perish from drought.

Even ancient rocks formed or deposited before the appearance of life on the earth show signs of terrific violence.

It has been maintained by some that the causes now at work altering the face of the world are sufficient to account for all the changes through which it has passed: but that is not so. None of the agents Nature now employs--rain, thaw, rivers, seas, volcanoes--would have been adequate to produce her ancient works.

To explain the external crust of the world, we require causes other than those present in operation, and a thousand extraordinary theories have been advanced. Thus, according to one philosopher, the earth has received in the beginning a uniform light crust which caused the abysses of the ocean, and was broken to produce the Deluge. Another supposed the Deluge to be caused by the momentary suspension of the cohesion of minerals.

Even accomplished scientists and philosophers have advanced impossible and contradictory theories.

All attempts at explanation have been stultified by an ignorance of the facts to be explained, or by a partial survey of them, and especially by a neglect of the evidence afforded by fossils. How was it possible not to perceive that the theory of the earth owes its origin to fossils alone? They alone, in truth, inform us with any certainty that the earth has not always had the same covering, since they certainly must have lived upon its surface before they were buried in its depths. If there were only strata without fossils, one might maintain that the strata had all been formed together. Hitherto, in fact, philosophers have been at variance on every point save one, and that is that the sea has changed its bed; and how could this have been known except for fossils?

From this consideration I was led to study fossils; and since the field was immense I was obliged to specialise in one department of fossils, and selected for study the fossil bones of quadrupeds. I made this selection because only from a study of fossil quadrupeds can one hope to ascertain the number and periods and contents of irruptions of the sea; and because, since the number of quadrupeds is limited, and most quadrupeds known, we have better means of assuring ourselves if the fossil remains are remains of extinct or extant animals. Animals such as the griffin, the cartazonon, the unicorn, never lived, and there are probably very few quadrupeds now living which have not been found by man.

But though the study of fossil quadruped be enlightening, it has its own special difficulties. One great difficulty arises from the fact that it is very rare to find a fossil skeleton approaching to a complete state.

Fortunately, however, there is a principle in comparative anatomy which lessens this difficulty. Every organised being constitutes a complete and compact system with all its parts in mutual correspondence. None of its parts can be changed without changing other parts, and consequently each part, taken separately, indicates the others.

Thus, if the intestines of an animal are made to digest raw flesh, its jaws must be likewise constructed to devour prey, its claws to seize and tear it, its teeth to rend it, its limbs to overtake it, its organs of sense to discern it afar. Again, in order to enable the jaw to seize with facility, a certain form of condyle is necessary, and the zygomatic arch must be well developed to give attachment to the masseter muscle. Again, the muscles of the neck must be powerful, whence results a special form in the vertebræ and the occiput, where the muscles are attached. Yet again, in order that the claws may be effective, the toe-bones must have a certain form, and must have muscles and tendons distributed in a certain way. In a word, the form of the tooth necessitates the form of the condyle, of the shoulder-blade, and of the claws, of the femur, and of all the other bones, and all the other bones taken separately will give the tooth. In this manner anyone who is scientifically acquainted with the laws of organic economy may from a fragment reconstruct the whole animal. The mark of a cloven hoof is sufficient to tell the form of the teeth and jaws and vertebræ and leg-bones and thigh-bones and pelvis of the animal. The least fragment of bone, the smallest apophysis, has a determinative character in relation to the class, the order, the genus, and species to which it may belong. This is so true that, if we have only a single extremity of bone well preserved, we may, with application and a skilful use of analogy and exact comparison, determine all those points with as much certainty as if we were in possession of the entire animal. By the application of these principles we have identified and classified the fossil remains of more than one hundred and fifty mammalia.

II.--What the Fossils Teach

An examination of the fossils on the lines I have indicated shows that out of one hundred and fifty mammiferous and oviparous quadrupeds, ninety are unknown to present naturalists, and that in the older layers such oviparous quadrupeds as the ichthyosauri and plesiosauri abound. The fossil elephant, the rhinoceros, the hippopotamus, and the mastodons are not found in the more ancient layers. In fact, the species which appear the same as ours are found only in superficial deposits.