Georges Cuvier, Discourse on the revolutionary upheavals on the surface of the globe. Paris, 1825.
Commander of the Legion of Honour and of the Order
of the Crown of Wurtemberg, Regular Councilor on the State Council
and the Royal Council for Public Instruction, one of the forty
members of the French Academy, Permanent Secretary to the Academy
of Sciences, Member of the Royal Academies and Societies of Science
in London, Berlin, Petersburg, Stockholm, Turin, Gottingen, Copenhagen,
Munich, Member of the Geological Society of London, of the Asiatic
Society of Calcutta, etc.
Since English and German translations of this Discourse have appeared separately, some people have wanted a French edition to be made available as well, something distinct from the major work it introduces. In acceding to this wish, I have sought to benefit from the observations of the different foreign editors and to follow the progress made since the publication of the previous edition in a science cultivated nowadays more keenly than ever. Finally, I thought it necessary to end the text with a summary listing of the species of animals which I have discovered and described in the major work, so that people who do not have the leisure time to plumb these difficult matters completely could derive from this text at least a general idea and appreciate both the rational arguments based upon these findings and the important consequences which result from them for the history of the earth and the people on it.
In my work on Fossil Bones, I set myself the task of identifying the animals whose fossilized remains fill the surface strata of the earth. This project meant I had to travel along a path where we had so far taken only a few tentative steps. As a new sort of antiquarian, I had to learn to restore these memorials to past upheavals and, at the same time, to decipher their meaning. I had to collect and put together in their original order the fragments which made up these animals, to reconstruct the ancient creatures to which these fragments belonged, to recreate their proportions and characteristics, and finally to compare them to those alive today on the surface of the earth. This was an almost unknown art, which assumed a science hardly touched upon up until now, that of the laws which govern the formal coexistence of the various parts in organic beings. Thus, I had to prepare myself for these studies through a much longer research into animals which presently exist. Only an almost universal review of present creation could provide some proof for my results concerning created life long ago. But at the same time such a study had to provide me with a large collection of equally demonstrable rules and interconnections. In the course of this exploration into a small part of the theory of the earth, I would have to be able to subject the entire animal kingdom in some way to new laws.
I was sustained in this double task by the constant interest which it promised to have and by service to the universal science of anatomy, the essential basis of all those sciences dealing with organic entities, and to the physical history of the earth, the foundation of mineralogy, geography, and, we can say, even of human history and everything really important for human beings to know about themselves.
If one finds it interesting to follow in the infancy of our species the almost eradicated traces of so many extinct nations, how could one not also find it interesting to search in the shadows of the earth's infancy for the traces of revolutionary upheavals which have preceded the existence of all nations? We admire the force with which the human spirit has measured the movements of planets which nature seemed to have concealed for ever from our view; human genius and science have stepped beyond the limits of space; some observations developed by reasoning have unveiled the mechanical workings of the world. Would there not also be some glory for human beings to know how to step beyond the limits of time and to recover, through some observations, the history of this earth and a succession of events which have preceded the birth of the human genus? No doubt the astronomers have proceeded more rapidly than the naturalists. The theory of the earth at the present time is rather like the one in which some philosophers believed that the sky was made of freestone [fine-grained sandstone or limestone] and the moon was as big as the Peloponnese. But, following Anaxagoras, Copernicus and Kepler opened up the road to Newton. And why one day should natural history not also have its own Newton?
In this discourse I propose above all to present the plan and result of my work on fossil bones. I will try also to sketch a rapid picture of the attempts made so far to reconstruct the history of the earth's upheavals. No doubt, the facts which I have discovered form only a really small part of those which must make up this ancient history; but several of these lead to significant consequences, and the rigorous way in which I have proceeded in determining them encourages me to believe that people will look on them as points definitely settled, things which will constitute a special age in science. Finally, I hope that their newness will excuse the fact that I focus the major attention of my readers on them.
My object will be, first, to show by what connections the history of the fossil bones of land animals is linked to the theory of the earth and why they have a particular importance in this respect. Then I will develop the principles on which rests the art of sorting out these bones, or, in other words, of recognizing a genus and distinguishing a species by a single bone fragment, an art on whose reliability depends the reliability of all my work. I will give a quick indication of new species, of genera previously unknown, which the application of these principles has led me to discover, as well as of the various sorts of formations which contain them. And since the difference between these species and those today does not exceed certain limits, I will show that these limits are considerably greater than those which today distinguish the varieties of a common species. I will thus reveal just where these varieties could go, whether by the influence of time, or climate, or finally domestication.
In this way, I will proceed to the conclusion (and I shall invite my readers to conclude with me), that there must have been great events to bring about the much greater differences which I have recognized. I will develop then the particular revisions which my research must introduce into the opinions accepted up to the present time about the earth's revolutions. Finally I will examine up to what point the civil and religious history of people agrees with the results of the observations dealing with the physical history of the earth and the probabilities which these observations set concerning the time when human societies could have established permanent homes and arable fields and when, consequently, societies could have taken on a lasting form.
When the traveler goes through fertile plains where tranquil waters nourish with their regular flow an abundant vegetation and where the ground, trodden by numerous people and decorated with flourishing villages, rich cities, and superb monuments, is never troubled except by ravages of war or by the oppression of men in power, he is not tempted to believe that nature has also had its internal wars and that the surface of the earth has been overthrown by revolutions and catastrophes. But his ideas change as soon as he seeks to dig through this soil, today so calm, or when he takes himself up into the hills which border the plain; his ideas expand, so to speak, with what he is looking at. They begin to embrace the extent and the grandeur of the ancient events as soon as he climbs up the higher mountains of which these are the foothills, or when he follows the stream beds which descend from these mountains and moves into their interior.
The lowest and most level land areas show us, especially when we dig there to very great depths, nothing but horizontal layers of material more or less varied, which almost all contain innumerable products of the sea. Similar layers, with similar products, form the hills up to quite high elevations. Sometimes the shells are so numerous that they make up the entire mass of soil by themselves. They occur at elevations higher than the level of all seas, where no sea could be carried today by present causes. Not only are these shells encased in loose sand, but the hardest rocks often encrust them and are penetrated by them throughout. All the parts of the world, both hemispheres, all continents, and all islands of any size provide evidence of the same phenomenon. The time is past when ignorance could continue to maintain that these remains of organic bodies were simple games of nature, products conceived in the bosom of the earth by its creative forces, and the renewed efforts of certain metaphysicians will probably not be enough to make these old opinions acceptable. A scrupulous comparison of the shapes of these deposits, of their make up and often even their chemical composition shows not the slightest difference between these fossil shells and those which the sea nourishes. Their preservation is no less perfect. Very often one observes there neither shattering nor fractures, nothing which signifies a violent movement. The smallest of them keep their most delicate parts, their most subtle crests, their slenderest features. Thus, not only have they lived in the sea, but they have been deposited by the sea, which has left them in the places where we find them. Moreover, this sea has remained in these locations, with a sufficient calm and duration to form deposits so regular, so thick, so extensive, and in places so solid, that they are full of the remains of marine animals. The sea basin therefore has provided evidence of at least one change, whether in extent or location. See what results already from the first inspections and the most superficial observation.
The traces of upheavals become more impressive when one moves a little higher, when one gets even closer to the foot of the great mountain ranges. There are still plenty of shell layers. We notice them, even thicker and more solid ones. The shells there are just as numerous and just as well preserved. But they are no longer the same species. Also, the strata which contain them are no longer generally horizontal. They lie obliquely, sometimes almost vertically. In contrast to the plains and the low hills, where it was necessary to dig deep to recognize the succession of layers, here we see them on the mountain flank, as we follow the valleys produced by their tearing apart. At the foot of the escarpments, immense masses of debris form rounded hillocks, whose height is increased by each thawing and each storm.
And those upright layers which form the crests of secondary mountains do not rest on the horizontal layers of hills which serve as their lower stages. By contrast, they sink under these hills, which rest on the slopes of these oblique strata. When we bore into the horizontal strata near mountains with oblique layers, we find these oblique layers deep down. Sometimes when the oblique layers are not very high, their summits are even crowned with horizontal strata. The oblique layers are therefore older than the horizontal layers. Since it is impossible, at least for most of them, not to have been formed horizontally, evidently they have been lifted up again and were in existence before the others which rest on top of them. (1)
Thus, before forming these horizontal layers, the sea had formed other strata. These were for some reason or other broken, raised up, and overturned in thousands of ways. As several of these oblique layers which the sea formed in a previous age rise higher than the horizontal layers which succeeded them and which surrounded them, the causes which gave these layers their oblique orientation also made them protrude above the level of the sea and turned them into islands or at least reefs and uneven structures, whether they were raised again by an extreme condition or whether a contrasting subsidence made the waters sink. The second result is no less clear or less proven than the first for anyone who will take the trouble to study the monuments which provide evidence for these results.
But the revolutions and changes which are responsible for the present state of the earth are not limited to the upsetting of the ancient strata and to the ebbing of the sea after the formations of new layers. When we compare together in greater detail the various layers and the products of life which they conceal, we soon realize that this ancient sea did not continuously deposit the same type of stones nor the remains of animals of the same species, and that each of its deposits did not extend over all the surface which the sea covered. Successive variations took place, of which only the first ones were almost universal; the others appear to have been considerably less. The older the layers, the more each of them is uniform over a great extent; the newer the layers, the more they are limited and subject to variation within small distances. Thus, the changes in the strata were accompanied and followed by changes in the nature of the liquid and of the materials which it held in solution. When certain layers, appearing above the sea, split the surface with islands and protruding ranges, different changes could have taken place in several particular ocean basins.
We know that in the midst of such variations in the nature of the liquid, the animals which it nourished could not have stayed the same. Their species, even their genera, changed with the layers; and although there are some returns of species within small distances, it is true to state, in general, that the shells of the ancient layers have forms unique to them, that they disappear gradually and do not show up in the recent layers, even less in the present sea, where we never discover species analogous to them. Even several of their genera are not found there. The shells of recent layers, by contrast, are generically similar to those which live in our seas. In the most recent and least solid of these layers and in certain recent and limited deposits there are some species which the most practiced eye would not be able to distinguish from those which the neighbouring coasts nourish.
Thus in animal nature a succession of variations has taken place, brought about by changes in the liquid where the animals lived or at least by variations which corresponded to those changes. And these variations brought by degrees the classes of aquatic animals to their present condition. At last, when the sea left our continents for the last time, its inhabitants did not differ much from those which the sea still feeds today.
Finally, we say that if we examine with even greater care the remains of these organic creatures, we come to discover in the middle of the marine strata, even the most ancient ones, layers full of animal or vegetable products from land and fresh water. In the most recent layers (i.e., the ones closest to the surface) there are some where land animals are buried under masses of marine creatures. Thus, not only did the different catastrophes which moved the layers gradually make the various parts of our continent rise up from the bottom of the sea and reduce the size of the sea basin; but this basin has been moved in several directions. Often the regions converted into dry land have been covered again by the seas, whether they have sunk or the waters have been carried above them. As for the particular matter of the soil which the sea uncovered in its last retreat, the part which human beings and terrestrial animals live on right now, it had already been dry land once and had nourished at that time quadrupeds, birds, plants, and land forms of all sorts. Thus, the sea which left that land had previously invaded. The changes in the heights of the oceans did not therefore consist only in one withdrawal more or less gradual, more or less universal. It was a matter of a succession of various eruptions and retreats. The result of these has definitely been, however, a general lowering of the sea level.
But it is also really important to note that these eruptions and repeated retreats were not at all slow and did not all take place gradually. On the contrary, most of the catastrophes which brought them on have been sudden. That is especially easy to demonstrate for the last of these catastrophes, which by a double movement inundated and later left dry our present continents or at least a great part of the land which forms them today. That catastrophe also left in the northern countries the cadavers of great quadrupeds locked in the ice, preserved right up to our time with their skin, hair, and flesh. If they had not been frozen as soon as they were killed, decay would have caused them to decompose. On the other hand, this permanent freezing was not a factor previously in the places where these animals were trapped. For they would not have been able to live in such a temperature. Hence the same instant which killed the animals froze the country where they lived. This event was sudden, instantaneous, without any gradual development. What is so clearly demonstrated for this most recent catastrophe is hardly less so for the earlier ones. The rending, rearranging, and overturning of more ancient layers leave no doubt that sudden and violent causes placed them in the state in which we see them. The very force of the movements which the bodies of water experienced is still attested to by the mountain of remains and rounded pebbles interposed in many places between the solid layers. Thus, life on this earth has often been disturbed by dreadful events. Innumerable living creatures have been victims of these catastrophes. Some inhabitants of dry land have seen themselves swallowed up by floods; others living in the ocean depths when the bottom of the sea was lifted up suddenly were placed on dry land. Their very races were extinguished for ever, leaving behind nothing in the world but some hardly recognizable debris for the natural scientist.
Such are the conclusions to which we are necessarily led by the objects which we meet at every step and which we can verify at every instant in almost every country. These huge and terrible events are clearly printed everywhere for the eye which knows how to read the story in their monuments.
But what is even more astonishing and what is no less certain is that life has not always existed on the earth and that it is easy for the observer to recognize the point where life began to deposit her productions.
Let us keep climbing. Let us move up towards the great mountain ridges, towards the terraced summits of the great ranges. Soon these remains of marine animals, those innumerable shells, will become increasingly rare and will disappear altogether. We will reach layers of a different sort, which will contain no vestiges of living things at all. However, they will show by their crystallization and by their very stratification that they were also formed in a liquid state. Their oblique orientation and their escarpments will indicate that they also have been overturned. The manner in which they slant under the layers with shells will reveal that they were formed before them. Finally the height of their bare and bristling peaks rising above all these layers with shells will show that these summits had already left the water when the layers with shells were formed.
Such are the famous primitive or primordial mountains which cross our continents in different directions, rising up above the clouds, separating river basins, holding in their perpetual snow the reservoirs which supply the rivers' sources, and forming something like the skeleton and rough framework of the earth.
From a long way away the eye perceives in the indentations which split up the crests, in the sharp peaks which bristle there, evidence of the violent manner in which they were uplifted, very different from those rounded mountains or hills with long flat surfaces where the recent mound always remains in the condition in which it was peacefully deposited by the most recent seas.
These signs become more evident as one approaches. The valleys do not have gentle slopes any more or those jutting angles facing indentations opposite, which seem to indicate the beds of some ancient water course. They grow bigger or smaller without any rule. Their waters sometimes extend into lakes; at other times they hurtle down in torrents. Sometimes the rocks, coming suddenly together, form transverse dams, from which these same waters fall in cataracts. The ripped apart strata, revealing on one side a sharp perpendicular edge, present on the other side large obliquely oriented sections of their surface. They do not correspond in height. Those which, on one side, form the summit of an escarpment, disappear on the other and do not reappear any more.
However, some great naturalists have managed to demonstrate that, in the middle of all this disorder, a certain order still reigns and that these immense ranges, as bristling and overturned as they all are, themselves follow a succession which is almost the same in all the large mountain ranges. The granite, they say, which forms the central crests of most of these ranges and which is the highest of all the rocks, is also the rock which disappears under all the others. It is the most ancient of those which we have been given to see in the place which nature put it, whether it owes its origin to a univeral liquid which, in earlier times, held everything in solution, or whether it was the first rock established by the cooling of a large fused mass or even by evaporation (2). Foliated rocks lean on the flanks of the granite and form the lateral crests of these large mountain ranges. Schists, porphyries, sandstones, and talus are mixed together in the strata. Finally granular marbles and other calcareous rocks without shells resting on schists form the outer peaks, lower terraces, and foothills of these ranges, and are the last work by which this unknown liquid, this sea without inhabitants, seems to have prepared the materials for the mollusks and zoophytes which soon must have deposited on the bottom an immense quantity of their shells or their coral. We even see the first products of these mollusks, these zoophytes, showing up in small numbers here and there among the latest layers of these primitive formations or in the part of the earth's crust which geologists have called the transitional areas. In these places we meet here and there layers with shells interposed with some granites more recent than the others, among various schists and between some late beds of granular marble. The life which wished to seize hold of this earth seems in these early times to have fought with inert nature which had previously dominated. Only after a relatively long time did life clearly get the upper hand, so that to life alone belonged the right to continue to increase the solid outer layer of the earth.
Thus it cannot be denied that the masses which today form our highest mountains were originally in a liquid state; for a long time they were covered by waters which did not sustain any life. Changes did not take place in the nature of the materials deposited only after the appearance of life. The masses formed previously changed, as well as those which were formed later. They have similarly provided evidence of the violent alterations in their positions. Some of these transformations took place at the time when these masses existed by themselves and were not covered with layers of shells. We have the proof of that in the overthrusting, tearing apart, and fissures which can be observed in these strata, as well as in those of later land masses, which, indeed, are more numerous and more marked.
But these primitive structures have experienced still other upheavals since the creation of the secondary formations and have perhaps caused or at least shared some of those which these secondary formations have themselves undergone. There are, in fact, considerable sections of primitive rocks totally bare, although in a lower location than many of the secondary formations. How could these not have been covered over again unless they appeared since the creation of these secondary formations? We find many voluminous blocks of ancient materials scattered in certain countries on the surfaces of secondary formations, separated by deep valleys or even by the arms of the sea from the peaks and crests where these blocks could have originated. It must be the case either that some eruptions threw them there or that the low places which stopped their movement did not exist at the time of their transport, or finally perhaps that the motion of the waters which carried them surpassed in violence anything which we can imagine nowadays (3).
Here then is a collection of events, a series of periods earlier to the present times, whose sequence can be verified without doubt, although the lengths of the intervals cannot be defined with precision. There are so many items which indicate the measure and the direction of this ancient chronology.
Let us now consider what happens today on the earth; let us analyze the causes which still disturb its surface and determine the possible extent of their effects. This part of earth's story is all the more important because for a long time we thought we could explain earlier revolutionary upheavals by present causes, just as we readily explain past events in political history, when we know well the passions and the intrigues of our own times. But we are going to see that unfortunately things are not the same in the history of physics. The thread of the processes is broken; nature's march has changed; and none of the agents which she uses today would have been sufficient to produce these ancient works.
There now exist four active causes which contribute to alterations on the surface of our continents: rains and thaws which erode the steep mountains and throw debris at their feet; the moving waters which carry away this debris and go on to deposit it in places where their current slows down; the sea which undermines the foot of high coasts to create cliffs there and which throws back mounds of sand onto coasts of low elevation; and finally volcanoes which break through solid strata and raise or scatter on the surface piles of the material which they emit (4).
Everywhere where the broken strata expose their edges on the sheer faces, every spring and even with each storm, fragments of their materials fall at the bottom, pieces which become round by rolling over each other. The pile of these fragments takes on a slope determined by the laws of cohesion, so as to form in this way at the foot of the escarpment a mound more or less high according to the quantity of the falling material. These mounds form the sides of the valleys in all the high mountains and get covered with a rich vegetation when the falling rocks from above begin to get less frequent. But their lack of solidity makes them subject to collapse themselves when they are undermined by streams. And thus it is that towns, rich and populous districts, find themselves buried under the fall of a mountain, that the course of rivers is interrupted, and that lakes form in places previously fertile and pleasant. But these large landslides are fortunately rare, and the major influence of these hills of debris is to furnish materials for the destructive work of water torrents.
The waters falling on the crests and summits of mountains, the vapours condensing there, or the melting snows descend by an infinite number of small rivulets down along the slopes; they remove small bits of the slope and leave traces of their passage in light grooves. Soon these trickles come together in more clearly demarcated channels which cut into the surface of the mountains. They flow out through deep valleys, which collect water at the foot of the mountains, and thus go on to form the streams and rivers which carry back to the sea the waters which the sea had given to the atmosphere. When the snows melt or there is a storm, the volume of these mountain waters, suddenly augmented, rushes forward with a speed proportional to the slopes. They go on to collide violently with the foot of the mounds of debris which cover the sides of all the high valleys. They carry away with them the already rounded fragments which make up these mounds and polish them further by the agitation. But as they come to more level valleys where the current slows down or to larger basins where they can spread out, the waters deposit on the shore the largest rocks which they have been rolling. The smaller debris is deposited lower down. Only the smallest pieces or the most imperceptible silt particles reach the large channel of the river. Often, indeed, the course of these waters, before forming the large river lower down, must cross a large deep lake, where the silt is deposited, and from the lake the water comes out clear. But the lower rivers and all the streams which arise in the lower mountains or in the hills produce also in the areas through which they run effects more or less analogous to those of the high mountain torrents. When they are swollen by large rainstorms, they attack the foot of earthy or sandy hills which they encounter in their flow and carry material from it onto the low areas which they flood. Each inundation takes away a certain amount. Finally, when the rivers reach large lakes or the sea, when the speed which carries along the silt particles begins to stop completely, the particles are deposited on the shores of the river mouth. They end up creating there land which pushes the shore out, and if this coast is such that the sea, in its turn, throws up sand and contributes to this accumulation, there are thus created provinces, entire kingdoms, generally the most fertile and soon the richest in the world, if the governments let industry do its work there in peace.
The effects which the sea produces in the absence of an interaction with rivers are much less pleasant. When the coast is low and the bottom sandy, the waves push the sand towards the shore. With each backward surge the sand dries off a little, and the wind, which almost always blows from the sea, throws it onto the beach. Thus dunes are formed, these small mountains of sand which, if human industry does not manage to fix them in place with suitable vegetation, move slowly but inexorably towards the interior lands and cover fields and houses, because the same wind which lifts the sand from the shore onto the dune throws it from the top of the dune onto the side opposite the sea. If the sand and the water lifted off with it are of the sort which can form a durable binding material, the shells and bones thrown onto the shore will become encrusted with it; the woods, trunks of trees, and plants which grow close to the sea will be covered over with these aggregates. Thus will originate what can be called hardened dunes, like the ones which are seen on the coasts of New Holland [Australia]. One can get a clear idea of them in the description which the late Perron has left (5).
When, by contrast, the coast is elevated, the sea, which can throw nothing up on it, carries on a destructive action. Its waves eat away at the foot and make all the height into a steep cliff, because the highest parts find themselves without support and fall continually into the water. There they are agitated in the flood tides until the softest and the loosest parts disappear. After being forcibly rolled around in all direction by the waves, the hardest parts form rounded pebbles or that sand which finish by accumulating in sufficient quantity to serve as a rampart at the foot of the cliff.
Such is the action of the waters on the firm land. We see that it usually occurs in stages and that these stages are distinct. The debris from the great mountain crests carried into the valleys; the particles from the hills and the plains carried right to the sea; alluvial deposits extending the coasts at the expense of the high places--these are the limited effects which vegetation generally confines. This process presupposes, moreover, the pre-existence of mountains, valleys, plains, and, in short, all the unevenness of the earth, and it could not therefore have been the origin of this unevenness. The dunes are a phenomenon even more limited, both with regard to their height and their horizontal extent. They have no connection at all with those enormous masses [deserts] whose origin geology is searching for.
As to the action which the waters carry out in their own depths, we cannot understand that very well; we can, however, to a certain extent determine its limits.
Lakes, ponds, swamps, openings to the sea where the streams fall, especially when the latter come down steep neighbouring hillsides, deposit on the bottom piles of silt, which would end up by filling in the waters if we did not take the trouble to clean them out. The sea constantly releases its sludge and sediments in ports and coves, in all places where its waters are the most tranquil. The currents shape them into piles or throw up onto beaches the sand which they take forcibly away from the bottom of the sea, in the process creating also sand banks and shallows.
Certain waters, after having dissolved the calcareous substances with carbonic acid, which is present in them in large amounts, give rise to crystals when this acid can evaporate, thus forming stalactites and other concretions. There exist strata which have crystallized haphazardly in fresh water sufficiently extensive to be compared to some of those which the ancient sea left. Everyone knows the famous limestone quarries in the neighbourhood of Rome, and the rocks of this stone which the River Teverone (Aniene) tears away and continuously works into different shapes. These two actions can combine; the deposits accumulated by the sea can be solidified by stalactites. When, by chance, abundant sources of material containing calcite or some other substance in solution happen to fall on the places where these mounds are formed there can appear aggregates where the products of the sea and those of fresh water can combine. The shores of Guadeloupe are like this; they provide shells of the sea and land and human skeletons all together. Another similar example is the sandpit in the region of Messina, described by Saussure, where the sandstone is formed by the sands which the sea deposited there and which consolidate in that location.
In the torrid zone, where there are numerous species of lithophytes [polyps the substance of which is stony or calcareous, as in some corals] and where they develop prolifically, their stony trunks are intertwined into rocks and reefs and rise right up to the level of the water, close off the entry to ports, and create terrible traps for navigators. By throwing sand and silt on the top of these reefs, the sea sometimes raises the surface above its own level and turns them into islands which a rich vegetation soon brings alive (6).
It is also possible that in some places animals with shells, as they die, leave behind their petrified remains and that in association with silt of varying solidity or by other binding materials, they form extensive deposits or varieties of shelled layers. But we do not have any proof that the sea might today encrust these shells with a covering as compact as marbles or sandstones, or even the rough limestone which we see enveloping the shells in our own strata. Even less do we find that the sea deposits anything of the more solid strata, the ones with more silica, formed before the layers containing shells.
Finally all these causes combined would not appreciably change the level of the sea, would not lay down a single stratum above this level, and, most importantly, would not produce the slightest mound on the surface of the earth.
It has been well urged that the sea has experienced a general diminution and that people have observed this in some places on the shores of the Baltic Sea (7). But whatever the causes of these phenomena, it is certain that they are not universal and that in the majority of ports where people are sufficiently interested to observe the height of the sea and where established ancient works provide sufficient means to measure the variations, the average sea level is constant. There is no general lowering, no universal encroachment of the land on the sea. In other places, like Scotland and several points in the Mediterranean, people think they have perceived, by contrast, that the sea is rising and today covers beaches previously above sea level (8).
The action of volcanoes is more limited, even more local than all those which we have just mentioned. Although we do not have any clear idea about how nature maintains these violent furnaces at such great depths, we do judge clearly by their effects the changes which they could have produced on the surface of the earth. When a volcano announces its presence, after some tremors, some shaking of the earth, it creates an opening for itself. Some rocks and cinders are thrown far out, and lavas erupt. The most viscous part runs out in long trails. The less viscous part stops at the edge of the opening and raises its contour, forming there a cone terminating in a crater. Thus volcanoes arise on the surface, after having altered that surface, out of materials previously buried in the depths. They form mountains. They have in earlier times covered some parts of our continents and have given rise suddenly to islands in the middle of the sea. But these mountains and islands were always composed of lavas. All their materials have gone through the effects of fire. Their shape is determined in accordance with the nature of materials which have run down from an elevated place. The volcanoes thus do not raise up or knock over the strata which cross their opening. And if some causes working in the depths have contributed in some cases to raise large mountains, this is not volcanic action as it exists in our times.
Thus, to repeat what we have said, it is vain for someone to seek in the forces which affect the surface of the earth today causes sufficient to produce the upheavals and catastrophes whose traces the earth's surface shows us. And if someone wishes to resort to constant external forces known nowadays, among them he will not find sufficient reasons for such revolutionary upheavals.
The pole of the earth moves in a circle around the pole of the ecliptic; its axis inclines more or less on the plane of this same ecliptic. But these two movements, whose causes nowadays are understood, are carried out in known directions and within known limits, and they are not at all proportional to effects like those whose magnitude we have just established. In every case, their excessive slowness would prevent them from explaining the catastrophes which we have just shown to have been sudden.
This last rationale applies to all slow actions which people have imagined, without doubt in the hope that their existence could not be denied, because it would always be easy to maintain that their very slowness renders them imperceptible. Whether this is true or not is inconsequential. Such forces explain nothing, because no slow action could have produced these sudden effects. Thus, whether there was a gradual diminution of the waters, whether the sea carried solid material in all directions, whether the temperature of the earth decreased or increased, none of these has overturned the strata, enclosed in ice large quadrupeds with their flesh and pelt, put on dry land shell fish still as well preserved today as if they had been caught while still alive, or finally destroyed entire species and genera.
These arguments have forcibly impressed the great majority of natural scientists. And among those who have sought to explain the present state of the earth, hardly anyone has attributed it entirely to slow causes, even less to causes working before our very eyes. This need to seek causes different from those which we see at work now is the same need which has led scientists to dream up so many extraordinary conjectures and made them commit errors and lose themselves in contradictions, so that the very name of their science, as I have said elsewhere, has for a long time been a subject of mockery for some prejudiced people who looked only at the systems which this situation created and who forgot the long and important series of established facts which it has made known (9).
For a long time we have accepted only two events, two periods of changes on the earth: the Creation and the Flood. All the efforts of geologists have tended to explain the present state of the earth by imagining a certain original state, later modified by the Flood. Each of them has speculated also about the nature of the causes, the actions, and effects of these events.
Thus, according to one (10), the earth was first given a smooth and light crust which covered seas in the depths and which broke open to produce the Flood. The debris formed the mountains. According to another (11), the Flood was brought about by a momentary suspension of mineral cohesion. The mass of earth was entirely dissolved, and the mixture penetrated by shellfish. According to a third (12), God raised the mountains in order to make the waters which had produced the Flood flow out, and put the waters in places where there were the most rocks, because otherwise it would have been impossible to hold them in. A fourth (13) created the earth with the atmosphere of a comet and had it overwhelmed by the tail of another comet. The heat which remained from its first origin excited all the living creatures to sin. Thus, they were all drowned, except the fish, who had apparently less excitable passions.
We see that, while entrenching themselves entirely within the limits set by the Book of Genesis, naturalists still gave themselves a large enough goal. They found themselves soon at an impasse. When they succeeded in seeing the six days of the Creation as so many indefinite periods, discounting the centuries, their systems took flight in proportion to the lapses of time which they were able to deal with.
Even the great Leibnitz amused himself, like Descartes, by making the earth an extinguished star, a glazed globe, on which vapours, trapped at the time of its cooling, formed the seas which later deposited calcified earth (14). Demaillet covered the entire globe with water for thousands of years. He had the waters gradually ebb. All the land animals at first lived in the sea. Even man started as a fish. And the author asserts that it is not rare to meet in the ocean fish which are only half human, but from them the species will become completely human one fine day (15).
Buffon's system is merely a development of Leibnitz's, only with the addition of a comet which by a violent shock caused the sun to emit the liquid mass of the earth at the same time as all the planets. From this theory one result is firm dating. For, by the present temperature of the earth, we can know how long it has been cooling. And since the other planets left the sun at the same time as the earth, we can calculate how many centuries the large ones still have to cool and at what point the small ones were already frozen (16).
In our time, freer spirits than ever before have also wished to busy themselves with this important subject. Certain writers have reproduced and enormously extended Demaillet's ideas. They claim that all was liquid at the beginning, that the liquid engendered at first very simple animals, like monads or other microscopic infusorian species, and that, with the passage of time and the development of different habits, the animal races became more complex and diversified to the point where we see them today. All these animal races have converted the water of the sea by degrees into calcified earth. The plants (on the origin and changes of which no one tells us anything) for their part turned this water into clay. But these two earths, by force of being stripped of the characters which life had imprinted on them, resolved themselves, in the last analysis, into silica. And lo and behold, for this reason the oldest mountains contain more silica than the others. All solid parts of the earth therefore owe their origin to living things, and without that life the earth would be still entirely liquid (17).
Some other writers have preferred Kepler's ideas. Like this great astronomer, they give the earth itself vital faculties. According to them, a fluid circles in the earth, and an assimilation takes place just as in animated bodies. Each of its parts is alive. Every elementary molecule has instinct and will; they attract and repel each other according to antipathies and sympathies; each sort of mineral can change immense masses into its own nature, as we convert our food into flesh and blood. The mountains are the respiratory organs of the earth, and the schists are the secretary organs. Through them sea water is decomposed to create the volcanic eruptions. The seams finally are the decaying teeth, the abscesses of the mineral kingdom, and the metals a product of decay and illness. That is why almost all of them feel unpleasant (18).
Even more recently, a philosophy which substitutes metaphors for rational argument, starting with the system of absolute identity or pantheism, ascribes the origin of all phenomena or, what in its eyes is the same thing, of all beings to polarization, like the two electricities, by calling all opposition and difference polarization. Whether we consider situation, nature, or function, this belief sees opposition in the following: God and the world, in the universe the sun and the planets, in each planet the solid and the liquid, and following this course, changing as necessary its tropes and its allegories, it reaches even the final details of organic species (19).
I must admit, however, that above we have chosen extreme examples and that not all geologists have carried the airing of their conceptions as far as those we have just cited. However, among those who have proceeded with more reserve and who have not looked for methods outside ordinary physics or chemistry, how much diversity and contradiction still rule!
According to one, everything was precipitated successively by crystallization and deposited almost in the same way as now. But the sea, which covered everything, ebbed by degrees (20). According to another, the materials of the mountains are constantly eroded, carried by rivers to the bottom of the sea, heated by an enormous pressure, and form layers. One day the heat which hardens these layers will lift them up again violently (21).
A third supposes the liquid divided into a multitude of lakes arranged in amphitheatres one above the other, which, after having deposited the strata with shells successively broke their dams to fill the ocean basin (22). By contrast, according to a fourth, tides of seven to eight hundred toises [i.e., 14 to 16 thousand metres] have from time to time carried away the depth of the seas and thrown them on the mountains and hills, in the valleys, or on the original continental plains.
A fifth has fall successively from the sky, like meteoric stones, the various fragments of which the earth is composed and which carry in the unknown beings whose remains they conceal the imprint of their strange origin (23). A sixth makes the earth hollow and places there a magnetic core which moves itself, under the influence of comets, from one pole to the other, pulling with it the centre of gravity and the mass of the seas, thus alternately flooding the two hemispheres (24).
We could cite still twenty other systems every bit as different as the above. And, just to make sure there is no mistake about it, our intention is not to criticize the authors of these systems. On the contrary, we recognize that these ideas have generally been conceived by men of wit and wisdom, who have not ignored the facts, several of whom have even traveled for a long time to examine them and have gathered a great deal of important scientific information.
From where then could such disagreements come in the solutions to a common problem among people who set out with the same principles? Could it not be the case that the conditions of the problem have never all been taken into account, that the problem remains, right up to today, poorly defined and capable of several answers, all equally good when we generalize about this or that condition, all equally bad when a new condition becomes recognized or when our attention thinks back to some acknowledged but overlooked condition?
To abandon this mathematical language, we will say that virtually all the authors of these systems, having paid attention only to certain difficulties which struck them more than others, determined to resolve those difficulties by more or less plausible means and put aside numerous other equally important difficulties. One person, for example, has seen only the difficulty of the changing level of the seas. Another has seen only the problem of dissolving all the terrestrial substances in the same single liquid. Finally, yet another has seen only the problem of having animals which he thought were from the torrid zone living in the glacial zone. Exhausting their intellectual energies on these questions, they thought they had done everything in imagining some means or other of responding to them. Furthermore, by neglecting all other phenomena, they did not even dream of ever determining with precision the measure and the limits of those phenomena which they were seeking to explain.
This point is particularly true for the secondary formations, which, however, form the most important and the most difficult part of the problem. For a long time we have concerned ourselves only very slightly with determining the sequence of layers for the establishing the strata on top of each other and the relationships between these layers and the plant and animal species whose remnants they contain.
Are there animals and plants unique to certain layers which do not occur in others? What are the species which appear first or those which come later? Do these two types of species sometimes appear together? Is there an alternating pattern in their return or, in other words, do the first ones return for a second time and then do the second ones disappear? Have these animals and plants all lived in the areas where we find their remains, or are there any which were carried there from somewhere else? Are they still alive today somewhere, or have they been destroyed completely or in part? Is there a constant connection between the age of these layers and the similarity or dissimilarity of their fossils with living things? Is there a climatic connection between fossils and those living things which resemble them the most? Is it possible to conclude from this that the transport of these beings, if there was one, took place from north to south or from east to west, or by radiating out and mixing? And can we distinguish the times of these transports by the layers which carry the imprints of these living things?
What is there to say about the causes of the earth's present condition, if one cannot reply to these questions, if one has not yet sufficient reason for choosing between the affirmative and the negative? Now, it is only too true that for a long time none of these points has been resolved beyond doubt and that we have hardly even dreamed that it would good to clarify them before making up a system.
One will find the reason for this odd situation if one reflects that geologists have all been either museum naturalists, who hardly ever examined the structure of mountains on their own, or mineralogists who have not studied with sufficient detail the innumerable varieties of animals and the infinite complexity of their various parts. The first have only made systems; the latter have provided excellent observations: they have truly laid down the foundations of the science. But they have not been able to raise an edifice upon it.
In fact, the purely mineral part of the important problem of the theory of the earth has been studied with an admirable care by de Saussure and developed astonishingly since by Werner and the numerous knowledgeable pupils whom he has trained.
The first of these famous men [de Saussure] for twenty years carefully traversed the most inaccessible areas, attacking in one way or another the mountains of the Alps by all their faces and fissures. He has revealed to us the entire disorder of the primitive formations and has traced very clearly the boundary which distinguishes them from the secondary formations. The second man [Werner], profiting from the numerous excavations made in the country which has the oldest mines [Saxony in present Germany], has established the laws of the succession of strata. He has shown their respective ages and followed each of them in all its changes. From him, and from him alone, reliable geology dealing with the mineral composition of the strata will begin. But neither Werner nor de Saussure has paid the strict attention necessary to sort out the species of organic fossils in each type of layer, since the time when the number of known animals has increased so enormously.
Certainly other scholars have studied the fossil remains of these organic bodies. They have collected them and drawn copies of them by the thousands. Their works will be valuable collections of materials. But more occupied with animals or with plants, considered in themselves, than with the theory of the earth, or looking upon these petrified remains or fossils as curiosities rather than as historical documents or, finally, contenting themselves with partial explanations for the deposit of each piece, they have almost always neglected to seek out general laws concerning the position or the relationship of the fossils with the strata.
However the idea of this research [into the relationships between the fossils and the strata] was very natural. How did we not see that it is fossils alone which are the key to the birth of a theory of the earth, that, without them, we would perhaps never have dreamed that in the formation of the earth there was a succession of epochs and a series of different events? Fossils alone, in fact, establish reliably that the earth has not always had the same crust, for we are certain that they must have lived on the surface before being thus buried below ground. It is only by analogy that we have extended to primitive formations the conclusion which the fossils provide directly about the secondary formations. If we had only formations without fossils, no one could have claimed that these formations were not formed all together.
Moreover, even though our knowledge of fossils has remained slight, it is once more through them that we have come to understand the little we do know about the nature of the earth's revolutionary upheavals. They have taught us that the layers which contain them were deposited gently in a liquid, that their variations corresponded to those of the liquid, that their exposure was brought about by the movement of this liquid and happened more than once. None of this would be certain without fossils
The study of the mineral aspects of geology, which is no less necessary and which, indeed, has for the practical arts a much greater utility, is nevertheless a lot less instructive concerning the matters under discussion.
We are in the most abysmal ignorance about the causes which could have created the variety in the materials which compose the strata. We do not even know the agents which could have held some of them in solution. We still argue about several, whether they owe their origin to water or to fire. Basically we can see from the above that we are in agreement on only a single point: we know that the sea has changed its position. And how do we know that, if not by the fossils? The fossils which have given birth to the theory of the earth have, at the same time, thus given the principal clues, the only ones which up to this point have been generally recognized.
This idea was the one which encouraged me to busy myself with the subject. But the field is immense. One man alone could with difficulty deal cursorily with a very small part of it. It was therefore necessary to make a choice, and I soon made it. The class of fossils which is the object of this work [i.e., quadruped fossils] attracted me at first sight, because I saw that it was at one and the same time the most productive of precise results and yet less well understood; it was also richer in new subjects for research (26).
It is noticeable, in fact, that the fossils of quadrupeds can lead, for several reasons, to more rigorous results than can any other organic remains.
First, they characterize in a clearer manner the upheavals which have affected them. Shellfish announce clearly that the sea where they were formed existed, but their changes in species could in a pinch result from slight changes in the nature of the liquid or merely in its temperature. They could have been a result of causes even more accidental. Nothing assures us that, in the depths of the sea, certain species, certain genera even, after having occupied the same fixed areas for greater or lesser periods of time, could not have been chased away by others. With the quadrupeds, by contrast, all is precise. The appearance of the bones of quadrupeds, especially those of complete bodies in the strata, tells us either that the layer itself which carries them was in earlier times dry land or that dry land was at least formed in the immediate area. Their disappearance confirms that this layer was flooded or that the dry land ceased to exist. Thus through these bones we learn with certainty the important fact of the repeated flooding by the sea. The seashells and the other marine products by themselves would not have taught us this. By a detailed study of these quadruped fossils we can hope to learn the number and times of these inundations.
Secondly, the nature of the revolutions which have altered the surface of the earth must have had a more decisive effect on the terrestrial quadrupeds than on the marine animals. Since these revolutions consisted, in large part, of displacements of the sea floor and since the waters must have destroyed all the quadrupeds which they caught, if their flooding was universal, it could have made an entire class extinct. Or if the flooding at any one time reached only certain continents, it could have destroyed at least the species unique to these continents without having the same influence on the marine animals. By contrast, millions of aquatic individuals could have been left on dry land or buried under new strata or thrown violently onto the shore, and their race could nevertheless have been saved in some more peaceful places from which the species again propagated after the disturbance of the seas had stopped.
Thirdly, this more comprehensive action is also easier to grasp. Its effects are simpler to demonstrate. For since the number of the quadrupeds is limited and most of their species, at least the big ones, are known, we have more ways of assuring ourselves if the fossil bones belong to one of them or if they come from an extinct species. Since we are, by contrast, a very long way from understanding all the shellfish and sea fish and since we are probably still ignorant of the majority of those which live in the depths, it is impossible to know with certainty if a species for which one locates a fossil is not still living somewhere. Thus we see scholars stubbornly striving to assign the name of Pelagic shells, that is to say, the shell fish of the high seas, to Belemnites, horned ammonites, and to other shell remains which have been seen only in the ancient strata. In so doing, they wish to claim that, if we have not yet uncovered any living specimens, that is because they live at depths inaccessible to our nets.
Without doubt naturalists have not yet crossed all the continents and do not even know all the quadrupeds which live in the countries they have traveled across. From time to time we discover new species of quadrupeds. And those who have not examined with care all the circumstances of these discoveries could believe as well that the unknown quadrupeds whose bones we find in our layers have remained hidden right up to the present time in certain islands which sailors have not yet encountered or in one or another of the vast deserts located in the middle of Asia, Africa, the two Americas, or New Holland [Australia].
However, if one examines closely the sorts of quadrupeds which we have discovered recently and the circumstances in which we have discovered them, one will see that there is little hope of some day finding those which we have so far seen only in fossils.
The moderately sized islands far from large land masses have very few quadrupeds, for the most part extremely small. When they do have large specimens, the fact is that they have been brought there from elsewhere. Bougainville and Cook found only pigs and dogs in the South Sea islands. The largest quadrupeds of the Antilles were the agoutis [rodents of the guinea pig family].
To be sure, the large land areas, like Asia, Africa, the two Americas, and New Holland [Australia] have large quadrupeds, and generally species unique to each of them. Thus, every time people discovered that certain land masses had remained isolated from the rest of the world, they have found there a class of quadrupeds entirely different from anything existing elsewhere. Hence, when the Spaniards crossed South America for the first time, they did not find there a single European, Asian, or African quadruped. The puma, jaguar, tapir, cabiai [water hog], llama, vicunas, sloths, armadillos, opossums, and all the monkeys were for them entirely new creatures of which they had no conception. The same thing happened again in recent times when we began to examine the coasts of New Holland [Australia] and the adjacent islands. The various kangaroos, phascolomes [wombats], marsupials, bandicoots, flying marsupials, platypuses, and spiny ant eaters simply astonished natural scientists by their strange appearances, which broke all the rules and fell outside all our systems.
Thus, if there remained some large continent to discover, we could again hope to learn about new species. Among these we could find some more or less similar to those whose remains the depths of the earth have revealed to us. But it is enough to glance at a map of the world and to see the countless directions in which navigators have criss-crossed the ocean, in order to conclude that there must be no more large land mass, unless it is in the region of the south pole, where the ice would not permit any remnant of life to survive. Thus only in the interior of the large spaces of the earth can we still expect to come across unknown quadrupeds. But with a little reflection, we will soon see that such an expectation is hardly more justified in this region than in the islands.
No doubt, the European traveler does not easily cross the vast extents of territory, deserted or supporting only ferocious peoples. That is especially true as far as Africa is concerned. But nothing prevents the animals from crossing these areas in every direction and from moving towards the coasts. Where there were large chains of mountains between the coasts and the interior deserts, they would always be interrupted by certain narrow passes to allow the rivers to get through. In the burning deserts, the quadrupeds follow by preference the borders of the streams. The people of the coasts also go up these streams and quickly learn, whether for themselves or from trade and the traditions of the people upstream, about all the noteworthy species which live up to the stream's sources. Thus, at no historical period has it taken very long for the civilized nations who have spent time on the coasts of large territories to know sufficiently well the large animals of the region or those with a striking appearance.
Established facts fit this line of reasoning. Although the ancients did not go beyond the Imaeus and the Ganges Rivers in Asia and although in Africa they did not go far south beyond the Atlas Mountains, they really knew about all the large animals in these two parts of the world. And even if they did not distinguish all the species, that is not because they could not see them or hear people talk about them, but because the similarity of these species did not allow them to recognize their characteristics. The only important exception which one might offer to my opinion is the Malacca tapir, recently sent from India by two young naturalists, students of mine, Duvaucel and Diard. This is, in fact, one of the finest discoveries to enrich natural history in recent times.
The ancients knew the elephant very well, and the history of this quadruped is more accurate in Aristotle than in Buffon. They were not ignorant even of some differences which distinguish African from Asian elephants (27). The ancients knew about the two-horned rhinoceros which modern Europe has not seen alive. Domitian displayed them in Rome and had them inscribed on his medallions. Pausanias describes them very well. The single horned rhinoceros, although its home was far away, they knew equally well. Pompey put one on display in Rome. Strabo gave an accurate description of another one of them at Alexandria (28). The Sumatra rhinoceros described by Bell and the one from Java discovered and sent back by Duvaucel and Diard do not appear to have inhabited the continent. Thus there is nothing astonishing in the fact that the ancients knew nothing about them. In addition they perhaps did not distinguish between the different rhinoceroses.
The hippopotamus was not so well described as the species mentioned earlier. But we find really exact depictions of them on the monuments representing Egyptian matters which the Romans left, such as the statue of the Nile, the Palestrine mosaic, and a large number of medallions. In fact, the Romans saw these animals several times. Scaurus, Augustus, Antoninus, Commodus, Heliogabulus, Philip, and Carinus (29) put them on display.
The two species of camel, the Bactrian and the Arabian, were already very well described and characterized by Aristotle (30).
The ancients knew about the giraffe, or camel leopard. They even saw one of them alive in Rome, in the circus, during the dictatorship of Julius Caesar, in the Roman year 708. Ten of them collected by Gordian III were killed in the secular games of Philip (31), a fact which ought to astonish us moderns who have only seen one in the fifteenth century (32)
If one reads with attention the descriptions of the hippopotamus provided by Herodotus and Aristotle, which are believed to be taken from Hecataeus of Miletus, one will find that they must have been made up of the descriptions of two different animals. One perhaps was the true hippopotamus, and the other was clearly the gnu (Antilope gnu, Gmel.), the quadruped which our natural scientists heard about only at the end of the eighteenth century. It was the same animal of which we had fabulous accounts under the name of catoblepas or catablepon (33).
The Ethiopian wild boar of Agatharchides, which had horns, was indeed our modern Ethiopian wild boar, whose enormous tusks deserve the name of horns almost as much as the elephant's tusks (34).
The bubal [species of antelope] and the nagor [Senegal antelope] were described by Pliny (35); the gazelle by Aelianus (36); the oryx [African antelope] by Oppian (37). The deer have been described since the time of Ctesias (38); the agazel [species of gazelle] and wild cattle are perfectly depicted on the Egyptian monuments (39). Aelianus provides a good account of the yak, or bos grunniens, under the name of the ox whose tail serves to make fly swatters (40).
The buffalo was not domesticated in the time of the ancients; but the Indian bull, which Aelianus mentions (41) and which had horns sufficiently large to hold three amphoras, was indeed a variety of buffalo, called arni. Even the wild bull with shrunken horns, which Aristotle places in the territory of the Arachotai (42), can only be the ordinary buffalo.
The ancients knew about cattle without horns (43), African cattle, whose horns are attached only to the hide and move with it (44), Indian cattle, which run as fast as horses (45); cattle which are no bigger than a billy goat (46), sheep with large tails (47), and Indian sheep as large as donkeys (48).
Although the evidence the ancients give us on the aurochs [European bison], reindeer, and elk is all jumbled up with fables, it always shows that they knew something about the animals, but that this knowledge, based on the accounts of crude people, had never been subject to a judicious critical evaluation (49).
These animals still inhabit the countries where the ancients put them and have disappeared only in regions too cultivated for their habitat. Aurochs and elks live today in the Lithuanian forests, which in previous times were continuous with the Hercynian forest. There are aurochs in the north of Greece, as in the time of Pausanias. The reindeer lives in the frozen territories up north, where it has always lived. There it changes colour, not through it own will but following the sequence of the seasons. It is through a series of hardly excusable misunderstandings that people have assumed that reindeer were found in the fourteenth century in the Pyrenees (50).
Even the polar bear was seen in Egypt under the Ptolemies (51). Lions and panthers were common at Rome during the games. People saw hundreds of them there and even some tigers. The striped hyena and the Nile crocodile appeared there. In the ancient mosaics preserved at Rome there are some excellent portraits of the rarest of these species. Among others, the striped hyena is seen perfectly represented in a portion kept in the Vatican Museum. While I was at Rome (in 1809), a paved mosaic of natural stones was discovered in a garden beside the Arch of Galienus, constructed in the Florentine style, depicting in a very good representation four Bengal tigers.
The Vatican Museum possesses a crocodile made of basalt almost perfect in its accuracy (52). One can hardly doubt that the hippotigre was the zebra, which, moreover, lives only in the southern parts of Africa (53).
It would be easy to show that the ancients noted with sufficient clarity almost all the species of monkeys in any way remarkable, under the names of pithecians, sphinxes, satyrs, cebuses, cynocephaluses, and cercopithecuses (54).
The ancients knew and described gnawers [or rodents] (55) including quite small species, when they had some noteworthy appearance or characteristic (56). But the small species are not relevant to our purpose, and it is sufficient for us to have shown that all the large species remarkable for some striking characteristic which we know about today in Europe, Asia, and Africa were already known by the ancients. From this we can readily conclude that if they did not mention the small ones or did not distinguish those which resemble each other closely, like the various gazelles and others, they were prevented from doing so by imperfect attention and method, rather than by climatic barriers. We conclude also that if eighteen or twenty centuries and the circumnavigation of Africa and the Indies have not added anything in this matter to what the ancients have taught us, it does not seem likely that the centuries to come will bring much to our posterity.
But perhaps some counter argument will be put, to the effect not only that the ancients, as we have just established, knew about just as many large animals as we do, but that they described several creatures which we do not have, that we are too quick to look upon these animals as fabulous creatures, that we should search for them again before believing that we have exhausted the history of created existence, and finally that among these allegedly fabulous creatures, when we understand them better, perhaps will be found the originals of our unknown fossil species. Some will even think that these various monsters, essential embellishments in the heroic story of almost every people, are precisely those species which it was necessary to destroy in order to permit civilization to establish itself. Thus, the Theseuses and Bellerophons would have been more fortunate than all our people nowadays, who have effectively driven away harmful animals but have still not succeeded in exterminating any.
It is easy to reply to this objection by examining the descriptions of these unknown living creatures and going back to their origins. The majority of them have a purely mythological source, and their descriptions bear the incontrovertible imprint of that, for one sees in almost all of them only the parts of known animals, recombined by a freewheeling imagination and contrary to all the laws of nature.
The ones the Greeks invented or arranged have at least a certain grace in their composition, similar to the arabesques which decorate some remains of ancient buildings, which the fertile paintbrush of Raphael has produced in great numbers. The forms which unite in them, no matter how repugnant to reason, offer shapes agreeable to the eyes. These are the light products of happy dreams, perhaps emblems in the eastern fashion, where people claimed to clothe in mysterious images some metaphysical or moral propositions. Let us excuse those who use up their time revealing the wisdom hidden in the sphinx of Thebes, the Pegasus of Thessaly, the minotaur of Crete, or the chimera of Epirus. But let us hope that no one will seriously search for them in nature. One might as well look there for the animals in Daniel or the Beast of the Apocalypse.
Let us not seek in nature further for the mythological animals of the Persians, offspring of an even more exalted imagination: the marticore or destroyer of men, which bears a human head on the body of a lion, with a scorpion's tail at the end (57), the griffon or guardian of treasures, half eagle, half lion (58), the cartazonon (59), or wild ass, whose forehead is armed with a long horn.
Ctesias, who affirmed that these animals exist, was considered, among many writers, an inventor of fables, whereas all he did was attribute reality to emblematic figures. These fantastic compositions have been found sculpted in the ruins of Persepolis (60). What did they signify? We will probably never know, but we can be sure they did not represent real living things.
Agatharchides, the other inventor of animals, probably drew his ideas from an analogous source. The monuments of Egypt still show us numerous combinations of parts of diverse species. The gods there are often represented with a human body and an animal head. We see there animals with human heads, which have produced the cynocephalids, sphinxes, and satyrs of the ancient naturalists. The custom of representing there in the same picture men of very different heights, the huge king or conqueror, the vanquished or the subjects three or four times smaller, would have given rise to the fable of the pygmies. In some recess of one of these monuments Agatharchides would have seen his carnivorous bull, whose muzzle, split right up to the ears, spared no other animal (61). But naturalists would certainly not swear by this animal, because nature does not combine cloven hooves or horns with incisor teeth.
Perhaps there were plenty of other figures just as strange, either in those monuments which could not endure or in the temples of Ethiopia and Arabia which the Mahommedans and the Abyssinians destroyed in their religious zeal. The monuments in India are aswarm with them. But their combinations are too extravagant to have fooled anyone: monsters with a hundred arms and twenty completely different heads are far and away too grotesque.
Even among the Japanese and the Chinese there are imaginary animals which they give out as real and which they even depict in their religious books. The Mexicans had them. It is the custom of all peoples, either in the ages when their idolatry is still crude or at a time when the meaning of these symbolic combinations has been lost. But who would dare to claim to find in nature these offspring of ignorance or superstition?
However, it has happened that some travelers, to enhance their reputation, have claimed to see these fantastic creatures or, through lack of attention and led into error by a slight resemblance, they have confused something alive with them. The large monkeys appeared to be real cynocephalids, true sphinxes, or real men with tails. Hence, Saint Augustine believed he had seen a satyr.
Some real animals poorly observed and poorly described would also have given birth to ideas about monsters, although founded on some reality. Thus no one can doubt the existence of the hyena, although this animal does not have its neck supported by just one bone (62), and it does not change its sex each year, as Pliny says (63). Thus, the carnivorous bull is perhaps only a rhinoceros with two distorted horns. De Welheim well states that the gold bearing ants of Herodotus are corsacs [Tartar foxes].
Among the ancients, one of the most famous animals is the unicorn. People have continued right up to our own time to seek it out or at least to find arguments to support its existence. Among the ancients, three animals are frequently mentioned as having only one horn in the middle of the forehead: the African oryx [a species of antelope], which also has cloven hooves, hair going in the wrong direction (64), a large size, comparable to a bull (65) or even a rhinoceros (66), and which people agree is shaped like a stag and a goat (67); the Indian ass, which has an uncloven hoof, and the monoceros, to use the correct name, whose feet are sometimes compared to those of a lion (68), sometimes to those of an elephant (69), an animal which is consequently supposed to be a fissiped [having divided toes]. The unicorn horse (70) and the unicorn bull are undoubtedly both related to the Indian ass, for even the bull has been depicted as having an uncloven hoof (71). If these animals existed as distinct species, I raise the question whether we would not have at least the horns in our collections. And what unmatched horns do we have there other than those of the rhinoceros and the narwhal?
How, after that, can we rely on the crude figures traced by savages on the rocks (72)? Not knowing about perspective and wishing to portray an antelope with straight horns in profile, they would have been able to provide it with only one horn, and lo and behold, all of a sudden an oryx. The oryxes of the Egyptian monuments are probably nothing other than products of the rough style imposed on the artists of that country by their religion. Many of their profiles of quadrupeds display only one limb in front and one behind. Why would they have shown two horns? Perhaps in the hunt someone chanced to get some individual animals which had accidentally lost one horn, as happens often enough with chamois and saigas [a form of antelope], and that would have been enough to confirm the error produced by these images. Probably this is the way people recently came across the unicorn in the mountains of Tibet.
Besides, not all the ancients by any means gave the oryx just one horn. Oppian expressly gives it several (73), and Aelianus refers to some oryxes who have four (74). Finally if this animal was a ruminant and had cloven hooves it would certainly have the frontal bone divided in two, and, according to the very apt comment of Camper, would have been unable to carry a horn on the suture.
But it will be said, what animal with two horns could have provided the idea for the oryx and demonstrate characteristics with which people confirm its shape, even deriving from it the single horn? I reply, with Pallas, that the animal is the antelope with straight horns, badly named pasan by Buffon (Antilope oryx, Gmel). It lives in the deserts of Africa and must come right up to the borders of Egypt. That is the animal which the hieroglyphs appear to have depicted. Its form is close enough to that of a stag; it is equal in size to the bull; the hair on its back points towards the head; its horns form terrible weapons, as piercing as darts and as hard as iron. Its fur is off white; its face carries black traces and stripes. There we have all that the naturalists have said about it. As for the fables of the Egyptian priests who justified the adoption of its image among the hieroglyphic signs, these stories were not necessarily based on nature. Thus, whether people saw an oryx lacking one horn; whether they took it for a regular living specimen, typical of the entire species; whether this mistake adopted by Aristotle was copied by his successors, all that is possible, even natural. It will, however, prove nothing about the existence of the unicorn species.
As for Indian ass, if one reads about the properties which the ancient attributed to its horn as an antidote for poisons, one will see that they are exactly the same as those Eastern people nowadays attribute to rhinoceros horn. In the earliest times, when this horn would have been brought among the Greeks, people would not yet have known about the animal which carried it. In fact, Aristotle makes no mention of the rhinoceros, and Agatharchides is the first to describe it. In the same way the ancients had ivory long before they knew about the elephant. Perhaps some of their travelers even named the rhinoceros the Indian ass, with the same justification that the Romans called the elephant the bull of Lucania. Moreover, everything which is said of the force, size, and ferocity of this savage ass fits the rhinoceros really well. Afterwards when those who knew more about the rhinoceros found in the earlier authors reference to an Indian ass, they accepted it, for lack of any critical study, as a separate animal. Finally, from this name people would have concluded that the animal must have had uncloven hooves. There is indeed a very detailed description of the Indian ass in Ctesias, but we have seen above that it was taken from the bas reliefs of Persepolis. Thus it must be discounted in the reliable history of the animal.
When at last some slightly more exact descriptions were made, ones which talked about an animal with a single horn but with several digits, people made of it yet a third species, named monoceros. These sorts of ambiguities are, by the way, all the more frequent in the ancient natural scientists, since almost all of them whose works we have were simple compilers. Aristotle himself frequently mixed up facts borrowed from somewhere else with those which he had observed for himself. Finally the skill of critical analysis was poorly understood then just as much by the naturalists as by the historians, which is saying a great deal.
From all these reasons and digressions, the result is that the large animals which we know existed in ancient times were known by the ancients and that the animals described by the ancients and unknown in our time were imaginary. Moreover, it thus follows that not a great deal of time was needed for the large animals of the three major parts of the world to become known to the people who spent time on the coasts of those regions.
We can also conclude from this that we do not have any large species to discover in America. If some of them lived there, there would be no reason for us not know about them. In fact, for one hundred and fifty years we have not discovered one. The tapir, jaguar, puma, cabiai, lama, vicuna, red wolf, buffalo or American bison, anteaters, sloths, armadillos are already in Margrave and in Hernandez, as in Buffon. One can even say that they are better there [in the former], because Buffon has muddled up the history of the anteater, failed to recognize the jaguar and the red wolf, and confused the American bison with the aurochs of Poland. It is true that Pennant is the first naturalist who clearly distinguished the small musk ox, but travelers had been pointing it out for a long time. The horse with cloven hooves in Molina was not described by the first Spanish travelers, but it is more than doubtful that it exists, and the authority of Molina is too suspect to adopt his account. It would be possible to characterize better the stags of America and India, which have not been well described. But so far as they are concerned, the case is the same as with the various antelopes among the ancients. The lack of a good method for distinguishing them and not the absence of opportunities to see them has led to their not being better understood. We can therefore say that the moufflon [wild sheep] of the Blue Mountains is up to now the only American quadruped of some size whose discovery is entirely modern. And perhaps it is only an argali [Asian rock sheep] which came across the ice from Siberia.
After that, how can we believe that the immense mastodons, the gigantic megatheriums, whose bones have been found in the earth in the two Americas, still live on this continent? How would they have escaped the notice of those nomadic people, who continuously cross the country in every direction and who themselves recognize that these creatures do not live there any more, because they have dreamed up a fable about their destruction, saying that they were killed by the Great Spirit, to prevent them from wiping out the human race. But we recognize that this fable arose through the discovery of bones, just like the story of the inhabitants of Siberia concerning their mammoth, which they maintain lives under the earth, like a mole, and like all those fables about the tombs of giants which the ancients located everywhere elephant bones were found.
Thus, we can readily believe that if, as we pointed out a moment ago, none of the large species of quadrupeds today buried in the regular rock strata is similar to the living species which we know about, that is not the result of simple chance, nor because those very species for which we have only the fossil bones are hidden in the deserts and have evaded all travelers up to the present time. We must, by contrast, look upon this phenomenon as having universal causes, and the study of it as one of the most appropriate ways to go back to the nature of these causes.
But if this study [of quadruped fossils] is more satisfying in its results than the study of the fossil remains of other animals, it is also bristling with far more difficulties. The shell fossils normally are present in their entirety, and with all the characteristics which can make them similar to analogous specimens in the collections or publications of natural scientists. Even the fish provide more or less complete skeletons. We can distinguish there almost always the general form of their bodies, and very frequently their generic characteristics and specific details which are derived from their hard parts. By contrast, with the quadrupeds, when we come up against the entire skeleton, for the most part we have difficulty drawing conclusions about characteristics deriving from the hair, the colours, and other marks which have vanished before they became fossilized. And indeed it is extremely rare to find a fossilized skeleton partially complete. Some isolated bones thrown all over the place, almost always broken and reduced to some fragments, that is all that our strata present to us from this class of animals, and that is the only resource of the natural scientist. Also it can be said that the majority of observers, alarmed at the difficulties, have skimmed over the fossil bones of quadrupeds, have classified them in a vague way, according to superficial similarities, or have not even dared to give them a name, so that this part of the history of fossils, the most important and instructive of all, is also the least cultivated (76).
Fortunately comparative anatomy possessed a principle which, well developed, was able to make all the trouble vanish: the principle of the correlation of structures in organic beings, by means of which each sort of creature could in a pinch be recognized by each fragment of each of its parts.
The entirety of an organic being forms a coordinated whole, a unique and closed system, in which the parts mutually correspond and work together in the same specific action through a reciprocal relationship. None of these parts can change without the others changing as well. Consequently, each of them, taken separately, points to and reveals all the others.
Thus, as I have said elsewhere, if the intestines of an animal are organized in such a way as to digest only fresh meat, it is necessary also that its jaws be constructed to devour its prey; its claws to seize and tear it apart; its teeth to cut and chew it; the entire system of its organs of motion to rush and catch the prey; its sense organs to perceive it from far away. It is even necessary that nature has placed in its brain the required instinct to know how to hide itself and set traps for its victims. Such will be the universal conditions for the kingdom of the carnivores; all animals destined for this kingdom will infallibly combine them, because its race would not have been able to survive without them. But under these general conditions, there exist particular ones, relative to the size, species, and habitat of its prey, for which the animal is structured. And from each of these particulars result the modifications of detail in the forms which derive from the general conditions. Thus not only the class, but the order and the genus, up to and including the species are found expressed in the form of each part.
In effect, in order for the jaw to be able to seize something, it must have a certain form of condyle [rounded structure at the end of bones], a certain coordination between the points of resistance and power with the fulcrum, a certain volume in the temporal muscle, which demands a certain breadth in the pit which contains it, and a certain convex shape in the zygomatic arch under which it passes. This zygomatic arch must also have a certain strength to support the masseter muscle [jaw muscle].
In order for the animal to be able to carry off its prey, it must have a certain power in the muscles which hold up the head, which results in a fixed shape for the vertebras where the muscles are attached to them and for the occiput [back of the skull] into which they fit. In order for the teeth to be able to cut through the meat, they must be incisors, and they must be more or less like incisors, according to whether they are more or less exclusively for biting through flesh. Their base must be even more solid in proportion to the quantity and size of the bones they would have to break apart. All these circumstances will have an effect also on the development of all the parts which serve to move the jaw.
In order for the claws to be able to seize the prey, there will have to be a certain mobility in the digits and a certain power in the nails. From this will result fixed forms in all the phalanges [bones in the digits] and the necessary distribution of muscles and tendons. The forelimbs will have to have a certain ability to turn, from which will result once more the fixed forms of the bones which make them up. But the bones of the forelimbs, which articulate with the humerus [bone of the upper arm], cannot change their structure without bringing about changes in that bone. The bones of the shoulder must have a certain firmness in the animals which use their front limbs for seizing prey, and from this will result again particular structures for them. The interplay of all these parts will demand certain proportions in all the muscles, and the patterns of the muscles thus proportioned will again determine more particularly the structures of the bones.
It is easy to see that one can draw similar conclusions for the posterior extremities which contribute to the general rapidity of movement, for the structure of the trunk and the shapes of the vertebrae which affect the ease and flexibility of movement; for the structures of the bones of the nose, eye socket, and ear, whose coordination is evident with the perfection of the senses of smell, sight, and hearing. In a word, the structure of the tooth entails the structure of the condyle, shoulder blade, nails, everything, just as the equation of a curve controls all its characteristics. Moreover, by taking each separate characteristic as the basis of a particular equation, we can find both the ordinary equation and all the other properties whatsoever, even the claws, shoulder blade, condyle, femur, and all the other bones each taken separately, reciprocally indicating or being indicated by the tooth. Starting with each of them, the person who possesses rationally the laws of the organic economy could reconstruct the entire animal.
The general meaning of this principle is clear enough in itself not to require a fuller demonstration. But when it comes to applying it, there are many cases where our theoretical knowledge of the coordination of structures will not suffice, unless it is based upon observation. We understand well, for example, that hoofed animals must all be herbivorous, because they have no way of seizing a prey. We also understand well that, not having any other use for their front legs than to hold up the body, they do not need a shoulder as strongly structured for power, from which result the absence of a clavicle and acromion [outer extremity of the shoulder blades] and the narrowness of the shoulder blade. Not having any need to turn their fore limbs, their radius will be knitted together with the ulna or at least articulated by the gynglymus, and not by a gliding joint with the humerus. Their herbivorous diet will require teeth with flat crowns to grind the seeds and herbage. It will be necessary for the crowns to be uneven and, for this effect, that enamel parts must alternate there with bony parts. Since this sort of crown requires horizontal movements for grinding, the condyle of the jaw cannot be as tight a hinge as in the meat eaters. It will have to be flat and also mesh with a facet of the temporal bone, which will be more or less flat. The temporal sockets, which will serve as an attachment for only a small muscle, will be neither very large nor very deep, and so on. All these matters are deduced one from the other, more or less according to their generality and from the manner in which some are essential and exclusively the property of animals with hooves and the others, although equally necessary in these animals, will not be exclusive to them, but can occur in other animals, where the remaining conditions still permit.
If we then go down the orders or subdivisions of the class of animals with hooves and examine what modifications the general conditions undergo or rather what particular conditions attach to them, according to unique characteristic of each of these orders, the reasons for these subordinate conditions begin to appear less clear. We still understand well enough in broad terms the need for a more complicated digestive system in the species where the dental system is less perfect. Thus we can say that those animals in which this or that order of teeth is missing must have been ruminants rather than something else; we can deduce from that a certain form of oesophagus and corresponding structures in the vertebrae of the neck, and so on. But I doubt whether we would have guessed, unless observations had noted the point, that ruminants would all have cloven hooves and that they would be the only animals to have them. I doubt whether we would have guessed that frontal horns occur only in this one class, that those among them which had sharp canines for the most part would lack horns, and so on.
However, since these interconnections are constant, they certainly must have a sufficient cause. But as we have no knowledge of that, we must make up for the inadequacy in the theory by observation. That serves to establish for us empirical laws which become almost as certain as rational laws, when they rest on observations which have been repeated often enough, with the result that nowadays anyone who sees only the track of a cloven hoof can from that conclude that the animal which left this imprint was a ruminant. And this conclusion is just as certain as any other in physics or morality. This single track reveals to the observer the structure of the teeth, jaws, vertebrae, and all the bones in the limbs, thighs, shoulders, and pelvis of the animal which has just passed by. That mark is more certain than all Zadig's [hero of a fiction by Voltaire, an expert tracker].
That there are, however, hidden reasons for all these interrelationships, that is something which observation itself can glimpse independently of general philosophy. In effect, when we create a table of these interrelationships, we notice there not only a specific consistency, if one can express oneself this way, between the structure of some organ and the structure of some other different organ. But we also notice a classic consistency and corresponding gradation in the development of these two organs, a fact which shows, almost as well as effective deduction, their mutual influence.
For example, the dental system of the non-ruminant hoofed animals is in general more perfect than that of animals with cloven hooves, or the ruminants, because the former have incisors or canine teeth, and almost always both of these on both jaws; and the structure of their feet is in general more complicated because they have more digits or the phalanges are less buried in the hoof, or more distinct metacarpals and metatarsal bones, or more numerous tarsal bones, or a fibula more distinct from the tibia, or finally because they often combine all these features. It is impossible to provide reasons for these interconnections, but what proves that they are not at all products of chance is that every time an animal with cloven hooves shows in the arrangement of its teeth some tendency to resemble the animals which we are discussing, it shows also a similar tendency in the structure of its feet. Thus the camels which have canine teeth and even two or four incisors on the upper jaw have an extra tarsal bone, because their scaphoid is not knitted to the cuboid, and very small claws with corresponding phalanges. Chevrotins [small species of musk deer], whose canines are very developed, have a distinct fibula along the length of the tibia, while the other animals with cloven hooves have for a complete fibula only a small bone joined at the base of the tibia. There is thus a constant harmony between two organs apparently extremely different from one another. And the gradations of their structures correspond without interruption, even in the cases where we cannot give a reason for their interrelationship.
Now, in thus adopting the empirical method as a supplementary means when our theory leaves us adrift, we reach details calculated to astonish. The least facet of bone and the least apophysis [protuberance of bone] have a determined character, relative to the class, order, genus and species to which they belong, to the point that every time we have only one bony extremity well preserved, we can, with effort, and with the assistance of a little skill in analogy and effective comparison, determine all those things just as certainly as if we possessed the entire animal. I have often experimented with this method on portions of known animals, before placing in it my total trust concerning fossils. But the method has always been so infallibly successful that I have not the slightest doubt about the certainty of the results which it has given me.
It is true that I enjoyed all the help which I could have required and that my fortunate position and diligent research for close to thirty years made available to me skeletons of all the genera and sub-genera of quadrupeds, even of many of the species in certain genera and several individual skeletons in some species. With such resources it was easy for me to make many comparisons and to verify in all their details the applications which I made of my laws.
I cannot deal any further with this method, and I must postpone such a discussion to the large work on comparative anatomy which I will soon publish, where one will find all its rules. However, an intelligent reader will already be able to derive a large number of these rules from the work on fossil bones, if he takes the trouble to follow all the applications which we have made of them there. He will see that this method alone has guided us and that it has almost always enabled us to link each bone to its species when it was from a living species, to its genus when it was a bone from an unknown species, to its order when it was from a new genus, and finally to its class when it belonged to an order not yet established, and to assign to it, in these three latter cases, the characteristics appropriate to distinguish it from the orders, genera, or the species most similar to it. Naturalists before me have not done much with this method for entire animals. In this way, I have determined and classified the remains of more than one hundred and fifty mammals or oviparous [egg laying] quadrupeds.
Considered according to their relationship with species, more than ninety of these animals were certainly unknown to naturalists up to the present time; eleven or twelve have a such a close resemblance to known species that we can hardly entertain a doubt of their identity; the others show many traits which resemble known species, but the comparison could not yet be made with them in a sufficiently scrupulous manner to erase all doubts. Considered according to their relationship with genera, of the ninety unknown species, almost sixty belong to new genera; the other species are related to known genera or sub-genera.
It is helpful also to consider these animals according to the classes and the orders to which they belong.
Of the one hundred and fifty species, about a quarter are oviparous quadrupeds, and all the others are mammals. Among the latter, more than half belong to non-ruminant hoofed animals. However, on the basis of these numbers it would be still premature to reach any conclusion concerning the theory of the earth, because they are not at all in proportions sufficiently significant statistically for the numbers of genera or species which could be buried in our strata. The bones of the large species, which more easily catch the attention of workers, have been more extensively collected, while those of the small species have been commonly neglected, unless chance has made them fall into the hand of a naturalist or unless some particular circumstance, like their extreme abundance in certain places, has attracted public attention.
What is more important, indeed what constitutes the most essential object of all my work and establishes its true relationship with the theory of the earth, is to know in which strata we find each species, and whether there are any universal laws relative to the zoological subdivisions or to the greater or lesser similarity between those species and today's. The recognized laws in this respect are excellent and very clear.
First, it is certain that the oviparous quadrupeds appear much earlier than the viviparous quadrupeds [those which give birth to live offspring], that they are even more abundant, stronger, and more varied in the ancient strata than on the present surface of the earth.
The ichthyosaurs, the plesiosaurus, several turtles, and several crocodiles are under the chalk in the lands commonly called the Jura. The monitors [a species of lizard] of Thuringia would be even older, if, as the Werner school maintains, the copper schists which contain them in the middle of so many varieties of fish believed to be fresh water creatures are among the most ancient beds of the secondary formation. The immense saurians [species of reptile] and the huge turtles of Maestricht are in the chalk formation itself. But these are marine animals.
This first appearance of bony fossils seems therefore already to announce that there existed dry lands and fresh waters before the formation of the chalk. But neither at this period nor during the time when the chalk was formed, nor even long after that, is there any encrustation of fossilized bones of terrestrial mammals or at least the small number of them which people claim forms only an almost inconsequential exception.
We begin to find the bones of marine mammals, that is to say, of lamantins [manatees] and seals, in the rough limestone with shells which covers the chalk in our regions. At that level, however, there is still no bone of a terrestrial mammal.
In spite of the most through research, I have not be able to discover any distinct trace of this class of animals [terrestrial mammals] before the formations deposited on top of the rough limestone. To be sure, some lignites and molasse [soft greenish sandstone] contain them, but I doubt very much whether these formations are all, as is believed, earlier than this limestone. The places where they have furnished bones are too limited, too few in number, so that one is obliged to assume some irregularity or some change in their formation. By contrast, as soon as we reach the formations above the rough limestone, the bones of land animals show up in large numbers.
Thus, since it is reasonable to believe that the shell fish and fish did not exist at the time when the primordial formations were established, we must also believe that the oviparous quadrupeds began at the same time as the fish, as early as the first ages which produced the secondary formations, but that the terrestrial quadrupeds did not come, at least in considerable numbers, until a long time later, when the rough limestones which contain most of our species of shell creatures, although in species different from ours, had already been laid down.
We should note that these rough limestones, the ones which supply Paris with construction materials, are the last layers which indicate a long and tranquil period of the sea above our continents. After them we certainly find again formations full of shells and other products of the sea, but these are loose formations, sands, marls, sandstones, clays, which reveal a more or less disturbed means of transport rather than a calm precipitation. If there are there some small regular rocky layers below or above these transported formations, they generally show indications of having been deposited in fresh water.
Thus, almost all the known bones of viviparous quadrupeds are either in formations made from fresh water or in these formations of transported material. Consequently there is every reason to believe that these quadrupeds began to live or at least to leave their remains in the layers which we can excavate only since the penultimate retreat of the sea, during the conditions which preceded its last irruption.
But there is also an order in the disposition of these bones among themselves, and this order reveals once more a very remarkable succession among the species. In the deposits we are quite sure of, at first all the genera unknown today, the palaeotheriums, the anoplotheriums, and so on, belong in the most ancient of formations of those under consideration here, those which rest immediately on top of the rough limestone. These are principally the ones which fill the regular layers deposited by fresh waters or the beds of transported material, formed a very long time ago, composed in general of sands and round pebbles. These were perhaps the first alluvial deposits of this ancient world. We also find with them some lost species of known genera, but in small numbers, and some oviparous quadrupeds and fish, all apparently fresh water creatures. The beds which contain them are always covered to a greater or lesser extent by layers of transported material filled with shells and other marine products.
The fossil mastodons, the most famous of these unknown species which belong to known genera or to genera very closely related to those that we do know about, like the elephants, rhinoceroses, and hippopotamuses, are not found with these older genera. We find them only in the formations of transported material, sometimes with sea shells, sometimes with shells from fresh water, but never in the regular rocky layers. Everything found with these species is either unknown, like them, or at least doubtful.
Finally, the bones of species which appear the same as ours are buried only in the last alluvial deposits formed on the edges of rivers or on the bottoms of ancient ponds or dried up swamps, or in the depths of peat layers, or in the cracks and caverns of some escarpments, or finally a little distance below ground in those places where they could have been buried by rock slides or by human beings. Their shallow position has also made these bones, the most recent of all, almost always the least well preserved.
We must not believe, however, that this classification of the various deposits is as clear as the classification of the species nor that it displays a similarly demonstrable character. There are numerous reasons why this is not the case.
Firstly, all my determinations of species were made on the bones themselves or on good diagrams. However, I have not often myself observed all the places where these bones were discovered. Very fr