PREFACE

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.

[INTRODUCTION]

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?

Exposition

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.

[THE GEOLOGICAL RECORD OF ANCIENT UPHEAVALS]

The First Appearance of the Earth

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 First Proofs of Upheavals

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.

Proofs that these Revolutions Have Been Numerous

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.

Proofs That These Revolutions Have Been Sudden

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.

Proofs That There Were Revolutionary Upheavals Before the Existence of Living Things

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.

[PRESENT GEOLOGICAL PROCESSES]

Examination of the Causes Which Are Still at Work Today on the Surface of the Earth

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).

Collapses

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.

Alluvial Deposits

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.

Dunes

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).

Cliffs

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.

Deposits Under the Waters

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.

Stalactites

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.

Lithophytes