Essay on the Theory of the Earth – Georges Cuvier

About the Work

Essay on the Theory of the Earth is a work of geological and natural-historical synthesis by Baron G. Cuvier, presented in English through a translation prepared from the last French edition, with geological illustrations and editorial apparatus supplied by Professor Robert Jameson of Edinburgh. The edition from which these notes are drawn is the fifth, issued by William Blackwood of Edinburgh and T. Cadell of London, and it carries a frontispiece showing a vertical section of the cavern at Gaylenreuth in Franconia—an image that announces the book’s central preoccupation with the buried remains of lost animals. The volume opens with a transcriber’s note explaining conventions of emphasis and annotation, followed by Jameson’s preface to the fifth edition, an advertisement to the fourth edition, and a preface to the third edition, before the essay proper begins.

The work is not a textbook of geology in the modern sense but an extended interpretive essay: an introductory discourse that gathers the findings of comparative anatomy, stratigraphy, and the study of fossil remains into a single argument about the history of the earth and its living inhabitants. Cuvier writes as a naturalist addressing both specialists and an educated public, and Jameson’s editorial contributions frame the essay for British readers by situating it within the geological debates of the early nineteenth century. The book’s subject matter ranges from the structure of mountain chains and the order of rock strata to the reconstruction of extinct quadrupeds, the interpretation of Egyptian monuments, and the chronology of ancient nations. Its tone is argumentative and cumulative: Cuvier builds his case by assembling observations, answering objections, and exposing the weaknesses of rival systems.

The essay is also, in a sense, a work of intellectual housekeeping. Much of its energy is directed against speculative cosmogonies—systems that explain the earth’s formation by a single sweeping principle—and in favor of a disciplined reading of the actual record preserved in the rocks. Jameson’s prefaces reinforce this aim, presenting Cuvier’s essay as the answer to those who dismissed geology as a tissue of ill-observed phenomena and boundless hypotheses. The book thus occupies a double position: it is a contribution to positive science and a polemic on behalf of a particular method.

Context

The intellectual setting of the essay is the geological ferment of the late eighteenth and early nineteenth centuries. Jameson’s preface to the fifth edition traces the rise of geology from a subject held in little estimation to one of wide popularity, and credits the Academy of Freyberg and its master Werner with giving the science its present condition. In Britain, Jameson notes, geology first took firm root in the north: in Edinburgh, Wernerian geognostical views were combined with Hutton’s theory, Hall’s experiments, and Playfair’s illustrations, and the labours of the Royal and Wernerian Natural History Societies spread inquiry throughout the Empire. On the Continent, Cuvier’s writings aided geology’s progress, and in Britain Cuvier was first known as a geologist by this very essay.

The preface to the third edition supplies a longer genealogy of fossil study. Naturalists had investigated fossil organic remains from an early period—Leibnitz himself drew and described fossil bones—and the Royal Society of London, through the memoirs of Sloane, Collinson, Lister, Derham, Baker, Grew, Hunter, Jacobs, Plott, and Camper, showed the importance attached to this branch in England. Ireland was not neglected, thanks to Graydon’s memoirs in the Royal Irish Academy Transactions. On the Continent, work appeared in the memoirs of Hollman, Beckman, and Blumenbach at Gottingen; of Gmelin, Pallas, Herrmann, and Chappe at Petersburg; of Geoffroi, Buffon, Daubenton, and Faujas St Fond in the old French Academy; of Astruc and Riviere at Montpellier; and of Collini at Manheim. But the geognostical relations of the rocks containing these remains were ill understood until Werner pointed out the mode of investigating them, and his views circulated from Freyberg through the writings and conversations of his pupils.

The essay also belongs to a period of intense debate about the age of the earth and the antiquity of nations. The advertisement to the fourth edition notes that the edition contains additional facts on the natural history of the earth, together with Cuvier’s discussions on the newness of the present continents as confirmed by the history of nations, and on proofs regarding the antiquity of nations alleged to be contained in astronomical and other monuments. These additions place the essay squarely within contemporary controversies over Egyptian chronology, Indian and Chinese antiquity, and the interpretation of zodiacs sculptured on temple ceilings. Cuvier’s intervention is distinctive because he brings to these debates not only geological but also textual and antiquarian evidence, and because he is willing to dismantle arguments that had been used to support extreme antiquity.

The book’s emotional register is set by a short reflection on fossil remains that stands near its opening. Fossil organic remains are relics of a primeval world, proclaiming the instability of earthly affairs and inspiring piety. If an antiquary digs from Herculaneum a coin, a vase, or a statue, we rejoice at seeing the mode of life, manners, and arts of an ancient people; if he finds an old record illustrating his country’s history, we are grateful. But among the ruins of the common country of the human race, at the great sepulchre of animated beings destroyed by fate, who can look without piety? We admire not the statues of Polycletus but the admirable monuments of Nature’s workmanship from the ruins of the great Herculeum overwhelmed by the ocean. This passage establishes the essay’s characteristic blend of scientific observation and moral reflection.

Structure of the Book

The volume is assembled as a layered document rather than a single continuous treatise. It begins with editorial matter: the transcriber’s note, Jameson’s preface to the fifth edition, the advertisement to the fourth edition, and Jameson’s preface to the third edition. These prefaces serve as a reception history and a methodological introduction, explaining why geology matters, what it requires of its students, and how Cuvier’s essay fits into the larger work on fossil organic remains of which it forms the introductory part. The reflection on fossil remains follows, setting the tone for what comes next.

The essay proper opens with an account of the earth’s past revolutions. Cuvier describes how the sea, before the horizontal strata were deposited, had formed other strata that were broken, raised, and overturned by problematical causes; how inclined strata rise higher than the horizontal strata succeeding and surrounding them; how the ancient sea did not always deposit the same minerals or the same species; and how displacements of strata were accompanied by changes in the fluid and dissolved matters. From this he moves to the suddenness of catastrophes, the evidence of large quadrupeds preserved in ice, and the proof that life has not always existed on the globe. The primitive mountains, the transition rocks, and the first productions of mollusca and zoophytes are described in turn, and the essay establishes the sequence of epochs anterior to the present.

A long middle section examines the causes of geological change and the diversity of systems that have been proposed to explain it. Cuvier reviews earlier systems—those of Leibnitz and Buffon—and more recent ones, including the revival of Demaillet’s ideas, the vitalist cosmologies that treat the globe as a living body, and the pantheistic philosophies that reduce all phenomena to polarization. He then catalogues the diversities of systems among more cautious geologists: precipitation by crystallization, deposition at the sea bottom followed by violent uplift, a series of lakes breaking their dikes, tides carrying bottom matter into mountains, meteoric stones bearing foreign remains, and the hollow globe with its loadstone nucleus. He asks why so much contrariety prevails among men proceeding on the same principles, and answers that the conditions of the problem were never all taken into consideration at once.

The essay then turns to the fossil record itself. Cuvier discusses the bones of viviparous quadrupeds, the order of their occurrence, and the succession of species. He distinguishes the oldest formations, containing the Palæotheria and Anaplotheria, from the alluvial formations containing fossil elephants, rhinoceroses, hippopotami, and mastodons, and from the most recent deposits containing species identical with living ones. He addresses the objection that extinct species might be varieties of existing ones, and answers it by examining the limits of variation in wild and domesticated animals. This leads into a detailed survey of fossil fauna from the period before the last catastrophe, including the ichthyosaurus, the plesiosaurus, the megalosaurus, the pterodactyli, and the crocodiles of the lias and oolite.

The later sections of the essay turn to chronology and the history of nations. Cuvier examines the mythological animals of the Persians and Egyptians, the fable of the unicorn, and the real animals that may have given rise to monstrous ideas. He then considers the evidence for the newness of the present continents drawn from the history of nations, the alleged antiquity of Indian and Egyptian civilization, the astronomical monuments of Upper Egypt, and the zodiacs of Dendera and Esne. The essay concludes with an appendix on the ibis, bringing the argument back to the natural history of a single species and its place in the ancient world.

Inside the Book

Front Matter and the Transcriber’s Apparatus

The volume opens with a transcriber’s note explaining the conventions used to render the text: italics marked by underscores, footnote anchors by bracketed numbers with the notes gathered at the end, superscripts by caret notation, and fractions shown either as symbols or in a/b form, with minor textual changes recorded at the close. The title page then identifies the work as the Essay on the Theory of the Earth by Baron G. Cuvier, Perpetual Secretary of the French Institute and Professor and Administrator of the Museum of Natural History, accompanied by geological illustrations from Professor Jameson. This is the fifth edition, translated from the last French edition with additions by both author and translator, published at Edinburgh by William Blackwood and at London by T. Cadell in 1827, and printed by P. Neill. A frontispiece presents a vertical section of the cavern at Gaylenreuth in Franconia.

Jameson’s Preface to the Fifth Edition

Robert Jameson begins by noting that geology, though now popular, was recently held in little esteem, and that some still dismiss it as a tissue of ill-observed phenomena and boundless hypotheses. Cuvier’s work, he argues, answers these imputations and demonstrates the accuracy, extent, and importance of geology’s facts and reasonings. The science, Jameson insists, requires chemistry, natural philosophy, astronomy, zoology, botany, and mineralogy; it discloses the history of the first origin of organic beings, traces their development from the monade to man, describes changes in plants, animals, minerals, atmosphere, and waters from the earliest periods to the present, and instructs us in the earliest history of the human species. It is likewise a foundation of agriculture and enables the search for materials of economical use. Geology arose in the Academy of Freyberg under Werner, to whom its present condition is owed, and the master should not be forgotten. In Britain it first took firm root in the north: at Edinburgh, Wernerian geognostical views were combined with Hutton’s theory, Hall’s experiments, Playfair’s illustrations, and the labours of the Royal and Wernerian Natural History Societies, spreading inquiry throughout the Empire. On the Continent, Cuvier’s writings aided geology’s progress, and in Britain Cuvier was first known as a geologist by this very essay. The preface is dated from the College Museum, Edinburgh, 25th November 1826.

The Advertisement and a Reflection on Fossil Remains

The advertisement to the fourth edition records that it contains additional facts on the Natural History of the Earth, together with Cuvier’s discussions on the newness of the present continents as confirmed by the history of nations, and on proofs regarding the antiquity of nations alleged to be contained in astronomical and other monuments; it is dated 2d April 1822. A reflection follows on fossil organic remains as relics of a primeval world, proclaiming the instability of earthly affairs and inspiring piety. If an antiquary digs from Herculaneum an ancient coin, vase, or statue, we rejoice at seeing the mode of life, manners, and arts of an ancient people; if he finds an old record illustrating his country’s history, we are grateful. But among the ruins of the common country of the human race, at the great sepulchre of animated beings destroyed by fate, who can look without piety? We admire not the statues of Polycletus but the admirable monuments of Nature’s workmanship from the ruins of the great Herculeum overwhelmed by the ocean.

Jameson’s Preface to the Third Edition

Naturalists, Jameson observes, investigated fossil organic remains early; the study is not entirely modern, for even in Leibnitz’s time that philosopher drew and described fossil bones. The Royal Society of London, through the memoirs of Sloane, Collinson, Lister, Derham, Baker, Grew, Hunter, Jacobs, Plott, Camper, and others, showed the importance attached to this branch in England, while M. Graydon’s memoirs in the Royal Irish Academy Transactions show it was not neglected in Ireland. On the Continent it was studied through the memoirs of Hollman, Beckman, and Blumenbach in the Gottingen Transactions; of Gmelin, Pallas, Herrmann, and Chappe in the Petersburg Memoirs; of Geoffroi, Buffon, Daubenton, Faujas St Fond, and others of the old French Academy; of Astruc and Riviere of Montpellier; and of Collini of the Academia Theodoro-Palatina at Manheim. But the geognostical relations of the rocks containing these remains were ill understood until Werner pointed out the mode of investigating them. His views circulated from Freyberg through the writings and conversations of his pupils, advancing this branch in Germany, France, and Great Britain. Petrifactions are no longer mere curiosities but important features in the strata of all regions; by their regularity and determinate distribution they afford characters distinguishing single beds and whole formations. This branch shows the commencement of organic being, the gradual succession from primeval coral near the primitive strata through shells, fishes, amphibious animals, and birds, to the perfect quadruped of alluvial land, and a geographical and physical distribution different from the present. The zoologist views fossil animals sometimes similar to living species, at other times far removed; comparing fossil orders, genera, and species with those now inhabiting earth and waters, he discovers a whole system of animals in the fossil state different from the present. The physiologist obtains new facts. Cuvier has eminently distinguished himself by numerous discoveries, accurate descriptions, and rational views; his great work on Fossil Organic Remains is the most splendid contribution to Natural History of this age, and the Essay on the Theory of the Earth is its introductory part, with the subject of the deluge forming a principal object.

Revolutions of the Globe and the Succession of Strata

The argument turns to the sea’s history before the horizontal strata were deposited: it had formed other strata that were broken, raised, and overturned in countless ways by problematical causes. Some inclined strata rise higher than the horizontal strata succeeding and surrounding them, proving that the causes of their inclination also made them project above sea level as islands, shoals, or inequalities—whether raised at one extremity or exposed by subsidence of the opposite end. This is the second result, as clearly demonstrated as the first. The passage then argues that revolutions were numerous. Comparing strata and their animal remains shows the ancient sea did not always deposit the same minerals or the same species, and each deposit did not cover the whole surface. Older strata are more uniform over great extents; newer ones are more limited and variable. Displacements of strata were accompanied by changes in the fluid and dissolved matters; once islands and ridges divided the seas, different changes could occur in particular basins. Aquatic animals changed with the strata: shells of ancient strata have peculiar forms and gradually disappear; recent strata shells resemble present-day genera; the latest, least consolidated strata contain species indistinguishable from neighbouring seas. A succession of variations in organic nature thus led aquatic classes to their present state; when the sea last retired from the continents, its inhabitants differed little from today’s.

The text says “last time” because even the oldest marine strata contain strata with terrestrial or fresh-water remains, and recent strata bury land animals under marine productions. Catastrophes caused continents to rise gradually and the ocean basin to shrink, but also caused numerous shiftings of the basin: dried lands were re-covered by waters, either engulfed or merely risen over.

The Order of Fossil Bones and the Succession of Species

Almost all known bones of viviparous quadrupeds lie either in fresh-water or alluvial formations, which suggests that land animals began to exist—or at least to leave remains in the strata—only after the sea’s second-to-last retreat and during the state preceding its final irruption. The bones themselves display a remarkable order, indicating a succession of species. All the now-unknown genera, such as the Palæotheria and Anaplotheria, whose position is thoroughly known, belong to the oldest of these formations, resting immediately on coarse limestone. These genera chiefly occupy regular fresh-water beds or very ancient alluvial beds of sand and rolled pebbles—perhaps the earliest alluvium of that ancient world. With them lie a few lost species of known genera, plus oviparous quadrupeds and fishes, apparently fresh-water inhabitants; their beds are always more or less covered by alluvial beds containing shells and other marine productions.

The most celebrated unknown species belonging to known or closely allied genera—fossil elephants, rhinoceroses, hippopotami, and mastodons—do not occur with those more ancient genera. They are found only in alluvial formations, sometimes with marine and sometimes with fresh-water shells, but never in regular stony beds; everything found with them is unknown or doubtful. Bones of species apparently identical with living ones occur only in the last alluvial deposits on river sides, dried pool or marsh bottoms, peat beds, rock fissures and caverns, or at small depths where buried by debris or human hands; their superficial position makes them, though most recent, almost always worst preserved.

Cuvier cautions that this classification of geological positions is not as certain as that of species. His determinations were made on the bones themselves or good figures, since he could not personally examine all discovery sites; he often relied on vague accounts from observers unaware of what to observe, and more often obtained no information. The repositories of remains are subject to far greater doubts than the bones: the same formation may appear recent at the surface and ancient where covered; ancient formations may be transported by partial inundations over recent bones, or fall on them by crumbling; ancient bones may be washed out and re-enveloped in recent alluvium; recent bones may fall into fissures of ancient rocks and be enveloped by stalactites. Each case requires analyzing circumstances that might disguise real origin, which collectors rarely recognized. Doubtful species—such as the horses and buffaloes occurring with elephants—may let geologists disinclined to accept his epochs argue against his system for years, conveniently using his own work. Yet he remains satisfied that a comprehensive view will lead others, as it led him, to conclude there were at least one and probably two successions in the class of quadrupeds before the present population of the earth’s surface.

Proofs that Extinct Quadrupeds Are Not Varieties of Living Species

Under this heading Cuvier addresses an objection already urged: why may not existing land quadrupeds be modifications of ancient fossil races, produced by local circumstances and climate change over long ages? This appears strong to those believing in indefinite alteration of organized forms. He answers from their own system: if species changed by degrees, traces of gradual modification should be found—intermediate forms between palæotheria and present species—yet none has ever been discovered. Why have the earth’s bowels not preserved monuments of so strange a genealogy, unless former species were as constant as ours, or the catastrophe destroying them left insufficient time for alleged variation?

To reply to naturalists who acknowledge varieties are restrained within limits fixed by nature, one must examine how far these limits extend—a curious, highly interesting, hitherto little-attended inquiry. Before entering it, a species must be defined: individuals descending from each other or common parents, and those resembling them as much as they resemble each other. Varieties are races more or less different sprung from it by generation; observations of differences between ancestors and descendants afford the only certain rule. Differences constituting variety depend on determinate circumstances and increase with their intensity. Most superficial characters vary most: colour depends on light, fur thickness on heat, size on abundance of food. In wild animals even these are greatly limited by natural habits. Though wolf and fox inhabit all climates from torrid to frigid zone, hardly any difference appears among them across that vast space beyond a little more or less beauty in their fur. Cuvier compared skulls of foxes from northern countries and from Egypt with those of France, finding no difference beyond what might be expected in different individuals. Wild animals confined within narrower limits vary still less, especially carnivorous ones; the only difference between the hyena of Persia and that of Morocco is a thicker or thinner mane.

Wild herbivorous animals feel climate more extensively, because food influence is added, differing in quantity and quality. Elephants of one forest are often larger than those of another; tusks are somewhat longer where food favours ivory production; the same may occur with horns of rein-deer and stags. But comparing two most dissimilar elephants, no slightest difference appears in number and articulations of bones, structure of teeth, etc. Wild herbivorous species seem more restrained from dispersing than carnivorous ones, because required food combines with temperature to prevent them. Nature also guards against alteration.

The Rising Beds of Rivers and the Growth of Land

M. de Prony, a member of the Institute and inspector-general of bridges and roads, communicated observations explaining changes along the shores of the Adriatic. Directed by government to investigate remedies for devastations caused by floods of the Po, he found that since the river was shut in by dikes, its bottom has risen so much that its water surface now stands higher than the roofs of houses in Ferrara. Its alluvial deposits have advanced into the sea so rapidly that, comparing old charts with the present state, the shore has gained more than six thousand fathoms since 1604—an average of 150 to 180 feet yearly, and in places 200 feet. The Adige and the Po are now higher than the land between them; only opening new channels in the low grounds they formerly deposited can avert disasters.

The same causes produced the same effects along the Rhine and Meuse branches; the richest districts of Holland continually see their rivers held up by embankments twenty to thirty feet above the land. M. Wiebeking, director of bridges and highways in Bavaria, wrote a memoir showing that the property of raising their beds is common, in greater or less degree, to all rivers.

Land additions along the North Sea have been no less rapid. They can be traced in Friesland and Groningen, where the first dikes, built by the Spanish governor Gaspar Roblès, date to 1570. A hundred years later, land had been gained in places to three quarters of a league beyond these dikes; Groningen, partly built on old land containing limestone with the same shells as the coarse limestone near Paris, is only six leagues from the sea. The author confirms these facts from personal observation, as stated by M. Deluc. The same phenomenon is observable along East Friesland, Bremen, and Holstein, where the enclosure period is known and the gain measurable. This new alluvial land is astonishingly fertile and valuable, since the ancient soil is covered with heaths and peat-mosses and unfit for cultivation; the alluvial lands alone support the populous cities built along these coasts since the middle ages.

The Zodiacs of Egypt and the Dating of Monuments

M. Delambre tested the circular planisphere by projecting the stars according to Hipparchus’s catalogue and theory, adjusting the longitudes until the solstice fell near the second of the Twins, and found the resemblance nearly reproduced. He judged it would have been closer still had the longitudes matched Ptolemy’s catalogue for the year 123 of the Christian era, and noted that shifting the reference back twenty-five or twenty-six centuries alters right ascensions and declinations enough to produce a different figure altogether. His calculations placed the sculptures after the age of Alexander. The planisphere itself was brought to Paris by MM. Saunier and Lelorrain, and M. Biot, working from precise measurements, determined that it depicted the heavens as they stood seven hundred years before Christ—though he did not conclude it had been carved then.

All such labours became superfluous once the Greek inscriptions on the monuments were copied and restored, and once M. Champollion discovered how to decipher hieroglyphics. The two scripts agree: the temples with sculptured zodiacs were built while Egypt was subject to the Romans. The portico of the temple of Dendera, by its Greek frontispiece, is consecrated to the safety of Tiberius, and on that temple’s planisphere the title Autocrator appears in hieroglyphics, probably referring to Nero. The small temple of Esne, whose origin had been placed between 2700 and 3000 years before Christ, bears a column sculptured and painted in the sixth year of Antonine, 147 years after Christ, in the same style as the adjacent zodiac. A mummy case brought from Thebes by M. Caillaud, inscribed in legible Greek with a young man who died in the ninth year of Trajan, 116 years after Christ, presents a zodiac divided at the same point as those of Dendera—a division marking some astrological theme relative to the individual, and probably equally applicable to the temple zodiacs, whether marking the theme of their erection, of the prince to whose safety they were consecrated, or of another important epoch.

Thus the conclusions drawn from ill-explained monuments against the newness of continents and nations are dissipated. The zodiac bears no certain, excessively remote date. Writers who claim it dates its own invention suppose the names and figures index the position of the colures at the moment of invention—a claim resting on three equally uncertain suppositions: the country of invention, the signification given the constellations, and the colures’ position relative to each constellation. Depending on the allegories imagined and which constellation the sun occupied, the date could vary by 13,000 years or more. Pluche generalized the ancient indications—the Ram announcing the sun’s elevation and the vernal equinox, Cancer his retrogradation to the summer solstice, the Balance the autumnal equinox, Capricorn the winter solstice—and, placing the inventors in a temperate climate, arrived at either 389 years before Christ, or 26,000 years, or 1600 to 1700 years before Christ, the epoch several celebrated men conferred on Chiron. Dupuis, requiring astronomy to precede all human institutions, sought another climate: in Egypt, Capricorn marks the Nile’s rise at the summer solstice, Aquarius and the Fishes the inundation, the Bull the time of labouring, the Virgin of reaping—yielding 15,000 years, on which he founded his celebrated work. Mr Hamilton, admitting Egyptian invention, imagined later allegories: the Virgin representing Egypt before the inundation, the Lion the season of ferocious animals.

The 15,000-year antiquity would absurdly imply that the Egyptians preserved signs for thousands of years after they no longer corresponded with their signification. M. Remi Raige supported Dupuis by arguing from Egyptian month names explained through oriental languages, finding in Ptolemy that epifi (Capricorn) commences June 20, immediately after the summer solstice. But Raige did not perceive that it was by chance that, five years after the battle of Actium, in the year 25 before Christ, at the establishment of the fixed year of Alexandria, the first day of Thoth corresponded with the 29th of Julian August. Only from that epoch did Egyptian months commence at fixed Julian days, and only at Alexandria; Ptolemy continued employing the ancient vague Egyptian year in his Almagest. Names might have been given to months or signs arbitrarily, as the Indians gave twelve names to twenty-seven months. The absurdity of preserving figures for 15,000 years would be more evident still with month names in constant popular use. What if figures and names were given without relation to the sun’s course—as their inequality, their extension beyond the zodiac, and their connection with neighbouring constellations seem to demonstrate? What if, as Macrobius says, each sign was an emblem of the sun in some effect without reference to months? What if names were given abstractly to divisions of space or time, applied by chance? These suggestions should give an ingenuous mind a distaste for seeking astronomical proofs of national antiquity. Even if such proofs were certain, what could they conclude against the great catastrophe, which has monuments amply demonstrative elsewhere? All that can be admitted is that astronomy was among the sciences preserved by those whom this catastrophe dispersed.

The antiquity of mining operations has likewise been exaggerated. A late writer imagined the mines of the island of Elba, judging from the rubbish, must have been wrought more than 40,000 years; another author reduced this to a little more than 5000 years, even supposing the ancients extracted annually only a fourth of the ore now wrought. Why suppose the Romans, consuming so much iron, derived so little advantage? Had these mines been wrought even 4000 years, how should iron have been so

Fossil Reptiles of the Secondary Strata

The passage traces fossil remains upward through the rock strata, beginning in the bituminous copper-slates where the first traces of quadrupeds appear as reptiles of the lizard family, resembling the large monitors of the torrid zone. Several individuals were found in the mines of Thuringia, among innumerable fishes of an unknown genus that appears to have lived in fresh water; monitors, too, are fresh-water animals. Higher lies Alpine limestone, resting on shell-limestone rich in entrochites and encrinites, forming the basis of much of Germany and Lorraine. In it were found skeletons of a very large sea-tortoise, its shell six to eight feet long, and those of another large oviparous lizard-like quadruped with a sharp muzzle.

Rising through sandstones bearing only vegetable impressions of large arundinaceæ, bamboos, palms, and other monocotyledonous plants, one reaches the Jura limestone, named for forming the nucleus of that mountain chain. Here reptiles reach full development in varied and gigantic forms. The middle part, composed of oolites and lias, or grey sandstone containing gryphites, holds two extraordinary genera combining oviparous-quadruped characters with cetacean organs of motion.

The ichthyosaurus, discovered by Sir Everard Home, has a lizard’

Erratic Blocks and the Puzzle of the New World

In the north of Holland, Germany, and the lands bordering the Baltic, enormous fragments of granite and syenite lie scattered within fixed limits. Humboldt took these as proof that the blocks had been carried southward from the Scandinavian peninsula during ancient revolutions of the globe, distributed like radii from a single centre, and that they never belonged to the granitic chains of the Hartz and Saxony, which they approach without ever reaching their base. Born on the sandy plains of the Baltic and knowing no other rock until the age of eighteen, Humboldt was curious whether the New World showed anything similar. He found no such block in the Llanos of Venezuela, though those plains are bordered to the south by an entirely granitic mountain group bearing traces of the most violent action; to the north, the granitic chain of the Silla of Caracas and of Portocabello is separated from the Llanos by schistose and calcareous ranges. He was equally struck by their absence on the banks of the Amazon, where La Condamine had already affirmed that from the Pongo of Manseriche to the strait of Pauxis not the smallest stone was observable. The basin of the Rio Negro and the Amazon is itself a Llano, differing from Venezuela and Buenos Ayres only in vegetation—grassy savannas in the north and south, thick equatorial forest in between. Nor did he hear of granitic blocks in the Pampas of Buenos Ayres or the savannas of the Missouri and New Mexico. The absence appears general in the New World, and probably equally so in the Sahara, since rocky masses piercing the soil must not be confounded with scattered fragments. These facts suggest that the Scandinavian blocks covering the sandy plains south of the Baltic, in Westphalia and Holland, owe their position to a particular debacle from the north—a purely local catastrophe. The old red conglomerate covering much of the Venezuelan and Amazonian Llanos contains fragments of the same primitive rocks as the neighbouring mountains, yet the convulsions evidenced there were not accompanied by circumstances favourable to transporting great blocks. The phenomenon is the more unexpected since nowhere is there a plain so continuous, prolonged with fewer interruptions to the abrupt declivity of a purely granitic cordillera. Before leaving Europe, Humboldt had already noted that there are no primitive blocks in Lombardy nor in the great plain of Bavaria, the bottom of an ancient lake elevated 250 fathoms above the ocean, bounded north by the granites of the Upper Palatinate and south by the alpine limestones, transition clay-slates, and mica-slates of the Tyrol.

Alpine Boulders Between the Alps and the Jura

Boulders of alpine rocks are found in the lower parts of Alpine valleys terminating in the great principal valley stretching between the Alps and the Jura, from the Lake of Geneva to the Lake of Constance, and almost everywhere in that valley. They occur sometimes 4000 feet above sea level on the Jura side facing the Alps, and in numbers in many Jura valleys. They occur only on the surface, never in solid rock, and never in the subjacent sandstone, marl, or conglomerate between the Alps and the Jura, though sometimes deep in the soil or embedded in river debris. Their enormous magnitude surprises travellers, some calculated to contain 50,000 cubic feet. Smaller masses are distinguished from river-borne ones by position—occurring on heights and acclivities where no river could have run—and may be confounded with blocks from decaying conglomerate, so caution is needed. Height bears no relation to magnitude: large blocks occur at considerable heights and in deep valleys, small masses in valley bottoms and high on mountains. They occur in heaps or singly, with no relation to magnitude. Smaller blocks are more or less rounded but seldom as much as river boulders; larger blocks are angular but not sharp-edged, though one must distinguish original angles from those produced by subsequent natural or artificial causes—masses are often blasted with gunpowder to clear fields or obtain building stones, and if left may mislead. The blocks vary in nature: some primitive, others transition and secondary, generally appertaining to formations nearer the central alpine chains than where found. Thus no transition rocks occur in gneiss valleys, no alpine limestone in transition valleys, and Jura limestone blocks appear nowhere but in Jura. Therefore all loose blocks between the Jura and the Alps belong to the high Alpine chains. Blocks differ by district: those of the Rhone basin and Lake of Geneva differ from those of the Rhine basin, which differ from those of the Aare, which differ from those of the Lake of Zurich and Limmat valley, which differ from the accumulations in the valley of the Reuss. Intermixtures rarely occur, a circumstance to be attended to. Accurate comparison shows the loose blocks of every known river basin agree with the rocks forming the sides of the upper parts of those high Alpine valleys immediately connected with these water basins: Rhine basin blocks resemble rocks of Bundten; Lake of Zurich and Limmat valley blocks resemble rocks of the Glarner land; Reuss basin debris consists of rocks of the mountains where the Reuss rises; Aare basin blocks resemble mountain rocks of the high Alps of Bern; and Rhone blocks occur in fixed positions.

Coastal Catastrophes and the Reclamation of the Marshes

A chronological record of destructive sea incursions along a northern coast follows. In 1075, the island of Nord Strand, then contiguous to the coast, was struck when the sea passed over its dike and formed large lake-like excavations within it. In 1114 and 1158, considerable parts of Eyderstede were carried away; in 1204, the part called Sudhever in the marsch of Uthholm was destroyed. In 1216, the sea rose so high that its waves passed over Nord Strand, Eyderstede, and Ditmarsch, killing near 10,000 inhabitants. In 1300, seven parishes in Nord Strand and Pellworm were destroyed. In 1338, Ditmarsch suffered a new catastrophe that swept away much of its side next to Eyderstede; the dike of the Eyder’s course between sand-banks was demolished, and the tides have since kept that wide space. In 1362, the isles of Fora and Sylt, then one, were divided, and Nord Strand, then a marsch united to the coast, was separated from it.

Survivors were long discouraged, diking only the least exposed meadow-land and leaving the rest to its fate. As natural causes raised the grassy sand-banks, later generations secured new grounds. In 1525, they addressed indentations in the marsches’ borders, planting stakes interlaced with osiers in front of creeks; the broken waves could no longer injure the marsch, and sediments formed solid fore-lands. In 1550, they raised dikes higher using wheelbarrows, then newly introduced, enlarging and deepening interior canals for earth to heighten dikes and extend their outer base. They began covering dikes with straw-ropes, but this preservative was ill managed and spread slowly, reaching North Strand and Eyderstede only about 1610 and 1612.

Earlier, Eyderstede’s safety was provided for differently.

The Question of Alternating Shell Beds

The argument turns first to a widely held inference: that alternating layers of fresh-water and marine shells in the newer flœtz rocks prove the sea repeatedly retreated and returned. Cuvier grants naturalists credit for raising the question but doubts their conclusion. In present seas and coastal ponds, he observes, testaceous animals thrive in both salt and nearly fresh water, and fresh-water species survive in salt; artificial means can convert sea inhabitants into fresh-water ones and the reverse, so fixing any species’ proper element is often impossible. Salt content alone decides nothing—food, soil, depth, the agitation or calm of the water, and the quality of air dissolved in it may matter just as much. An excellent observer, writing in support of fresh-water formations, showed that no unerring character distinguishes sea from fresh-water shell-fish. Even granting such a line could be drawn, the real question concerns neither existing shell-fish nor present waters: either the animals lived in the very water from which the beds precipitated, or their water was displaced by other water bearing the precipitating materials. In the first and more generally admitted case, that ancient fluid differed so greatly from any present salt or fresh water that present inhabitants teach us nothing about former ones—yet our sea and land waters resemble each other far more than either resembles that fluid. Otherwise the only difference between fresh and salt formations is that the former’s bottom once held land water, and the notion of enclosed basins and isolated formations long remained unsatisfactory. One may ask, too, on what grounds the former sea was credited with a continual possession of some salt, when salt precipitates appear only at intervals after long interruptions; if the sea sometimes held much salt and sometimes little, it might sometimes have held none. Tellingly, the rock beds most nearly related to salt formations contain no petrifactions at all, so the supposed marine animals are absent precisely in the periods that give direct evidence of salt water.

Conglomerates as Monuments of Destruction

Conglomerates, or reproduced stone, are next cited as evidence of violent revolutions and deluges. Cuvier allows that more investigation remains possible—some formations now passing for sandstone might be original chemical productions, though he will not go as far as Mr Gerhard, who treats greywacke as an immediate precipitate from the atmosphere. Still, genuine conglomerates persist from the transition period through the later formations, standing as monuments of destruction and renovation: the Codices rescripti of Earth’s archives, from which the antiquarian will one day decipher almost obliterated traces of her former condition. Though conglomerates deviate from chemical productions, they share one characteristic: with few exceptions, the older ones are less varied and more extensively distributed than the newer, and the newest dwindle into mere local appearances. Beds never abandoned by the sea might be assailed by floods and currents and shattered, their fragments reuniting into solid rock through dissolved matter; but many conglomerates were plainly deposited on dry land, like our gravels. Jupiter, deciding to destroy the sinful world by water, is less justly considered their author than Saturn, who devoured his children. Less metaphorically, conglomerate origin may resemble the origin of rock fragments and boulders today: rock fractured by alternating heat and cold, by air and atmospheric water, falls into pieces that water carries and gradually rounds, the fragments becoming more globular the farther they travel from their source. Long continual rolling during rounding is more efficacious than rapid violent impetus; here, as in many geognostic appearances, time rather than force counts. Weathering—first disunion, then progressive disintegration, the blunting of edges and corners, the diminution of fragments—shapes boulders and fragments as much as the mechanical operation of water, and much alluvial land owes its existence to this cause. If conglomerates originate like rolled gravel, they still testify to the elevated station of neighbouring water, since conglomeration could occur only under water; with few exceptions they occupy incomparably greater elevation than coal formations or the beds enclosing land-animal remains.

Change from Dry Land to Sea Bottom

Geognosy contains many facts explainable only by a change from dry land to sea bottom, though knowledge remains too imperfect to conjecture how many changes occurred, whether they began at the same or different periods in various quarters, or whether they were local or universal. These changes appear neither sudden nor violent, but proceed with silent, regular steps from similar concealed causes—such as the universal retreat of waters from their original height to the present ocean bed. Cuvier rejects the geologists who would divert the world from its axis to explain surface inequalities, at whose command Earth opens to engulf the sea or Heaven’s floodgates pour another ocean. Reflecting on the devastation wrought by earthquakes, inundations, and mountain falls—even merely local ones—one must ask how order, regularity, and connection in the rock strata could possibly survive if such accidents happened worldwide with such mechanical energy. All knowledge of Earth’s structure and inhabitants declares quiet, uninterrupted, continually progressive advancement. Across the geological epochs, rock formations follow one another, the later sufficiently similar to the earlier to indicate a common origin, terminating in simple formations resembling those of the present. When the precipitates were exhausted and the structure completed—or even earlier—destruction commenced: not a violent destruction tearing mountains asunder, no uproar of nature or gigantic struggle of the elements, but the decomposition of rock strata to greater or lesser depth by partly chemical, partly mechanical, slow powers, their intensity compensated by their endurance. By common law, deficiency of power is supplied by duration of time; of all the oracles consulted on Earth’s formation, none makes such important revelations as the oracle of the age of mountains. These surface operations produced Earth’s present figure, designing it for numerous organic beings. This appears as soon as a suitable element occurred: first in water, then land animals; like rock formation, a regular succession of organic formations, the later always descending from the earlier, down to the present inhabitants and the last created being to exercise dominion. But here occurs an important distinction: the organic world, with youthful vigour renewing itself, follows a different law from the mineral.

The Limits of Water’s Erosive Power

The argument then asks what water can actually do to solid rock. Present-day water, acting alone, has no true erosive power on solid, aggregated rock. The evidence: erosion never occurs at the sources of powerful springs—the pebbles there were carried off long ago, and mosses growing abundantly on rocks at water level and in torrent beds have nothing to fear from solid bodies. The same holds for stretches immediately below a lake or great excavation capable of arresting hard bodies carried by a river; there mosses appear in abundance because only water acts on them. Rivers, as they move away from the lofty mountains where they rise, often gain volume what they lose in velocity, but size rarely compensates for rapidity. Large rivers retain enough transporting power to carry obstacles opposing their progress, yet their results are far less striking than those of torrents. When flooded or changing course, they stir up the earth and mobile sand covering their bottom, especially toward their edges, and transport it some distance; but they scarcely move pebbles larger than an egg, which were brought there in other times and circumstances. By transporting comminuted and mobile mineral matters, they deposit them where the current relaxes, raising the bottom of their bed; they then seek a new passage amid barriers they themselves constructed.

The Fossil Elephant and the Great Mastodon

Cuvier turns to the fossil elephant, the mammoth, distinguished by an elongated skull, concave forehead, and very long tusk-sockets that must have greatly altered its proboscis and physiognomy. Its bones are found only in the fossil state, never fresh, and are best preserved in the north. It more closely resembles the Indian than the African elephant, though clumsier in proportion, and some individuals bore two kinds of hair—red wool and stiff black bristles forming a mane—suggesting it could support, even prefer, cold climates. Its remains lie in alluvial and superficial strata, mingled confusedly with rhinoceroses, oxen, horses, and marine animals, some shells still adhering to the bone. Three sites—Tonna, Canstadt, and the Forest of Bondi—show striking resemblance. The bones are not rolled; ridges and apophyses remain unworn, epiphyses often attached, proving the carcasses were not violently transported but lay stripped and separated at the bottom of the fluid. The elephants therefore dwelt where their bones now lie, destroyed by a sudden revolution or a climate change preventing propagation. Perfect preservation in Siberia demands immediate ice envelopment, which refutes gradual cooling. Since remains prove the species once lived in America, where it no longer exists, Cuvier concludes the fossil elephant is an extinct species, destroyed by the same great catastrophe.

The Great Mastodon resembled the elephant in tusks and skeleton but for its peculiar grinders, which constitute a different genus. It fed like the hippopotamus and boar on roots and fleshy vegetables, drawn to marshy places, yet was a true land animal. Its bones are commonest in North America, better preserved than any other fossil bones, yet no authentic testimony supports living mastodons—journal accounts are unconfirmed fables.

The Bone Caves and Their Contents

A note follows on the extraordinary accumulations of fossil bones in limestone caves, long a subject of inquiry. Bones were once sold as fossil unicorn for medicine. The most ancient celebrated cave is Bauman’s in Blankenburg, described by Leibnitz, its bones mostly of the bear genus. The Kirkdale discovery became famous, its specimens distributed to York, Whitby, Bristol, the British Museum, Oxford, Cambridge, and Edinburgh, though the finest collection went to Cuvier in Paris. Most bones belong to hyenas of the same species as those in German caverns, alongside elephant, hippopotamus, horse, ox, rabbit, and field-rat, plus tiger, wolf, fox, and weasel. All lie broken and gnawed, with tooth-marks and hyena excrements intermixed.

The cavern-bearing hills resemble each other: all limestone, all producing stalactites. Bones are detached, scattered, partly broken, but never rolled—hence not brought from a distance by water—still in true animal nature, containing much gelatine, not petrified. The animal-matter-penetrated earth envelops bones of all species indiscriminately, proving they were interred by the same causes. What renders the phenomenon striking is that the most remarkable bones are the same across more than two hundred leagues: three-fourths belong to extinct bear species, half the remainder to an unknown hyena. The Kirkdale Cavern is a notable exception, with hyena predominating and no bear bones. Species common in alluvial formations are rare in the German caves, while carnivora bones, so numerous in caves, are rare in the great alluvial strata—proving these animals lived together in the same countries and epoch.

Cuvier concludes only three causes could have placed these bones in the caves: animals inhabited them and died peaceably; inundations carried them in; or they were enveloped in rocky strata whose dissolution produced the caverns. The last is refuted because the strata containing the caves hold no bones; the second by the entireness of the smallest prominences, which forbids thinking they were rolled. We must therefore say these caves served as retreats to carnivorous animals, which carried there the animals forming their prey. Hyena bones are no less broken than herbivorous ones, concluding hyenas devoured their own dead, as they still do. The establishment of these animals in the caves took place at a much later epoch than the formation of the great rocky strata.

The Scholarly Apparatus

The remaining notes form an extensive apparatus of citations and brief argumentative asides. The author’s conclusion that certain transported blocks were moved after the deposition of sandstones and conglomerates is compared to torrents, though the editors object that the great size of the blocks and deep valleys militate against this. Notes cite M. de Hof on historical changes to the earth’s surface, the Swedish opinion that sea level is falling, and the Temple of Serapis showing local risings against thousands of Roman quays showing no relative change. The author apologizes for having said geology had become ridiculous, expressing only a fact, not his own opinion.

A long series lists historical geological theorists—Burnet, Woodward, Scheuchzer, Whiston, Leibnitz, Telliamed, Buffon, Lamarck, Hutton, and others—and cross-references Cuvier’s own researches on elephants, rhinoceros, hippopotamus, deer, and oxen. The Aurochs is distinguished from the extinct Urus; Buffon is corrected on the rein-deer’s range. An anchylosed hyena skeleton explains the Arab notion of invincible obstinacy, and the belief that the hyena changes sex is corrected. The longest note describes mutilated skeletons found near Port de Moule, Guadaloupe, in a tufa of shell and coral debris, discovered in 1805, one sent to the British Museum, another figured in Plate II.

Egyptian and Indian Astronomy

The final notes address Indian and Egyptian astronomy. Laplace and Mr Davis are cited on Indian astronomical calculations; Mr Bentley on the antiquity of the Surya-Siddhanta; Delambre on Indian astronomy; Sir William Jones on the Indian zodiac. A striking anecdote follows: Wilfort asked his pundit to point out the constellation Antarmada, and the pundit immediately indicated Andromeda, then brought a rare Sanskrit book containing figures of Capeya, Casyape, Antarmada chained with a fish, and Parasica holding a monster’s head with snakes for hair—identified as Perseus, Cepheus, and Cassiope, though the editor cautions the pundit became much suspected.

A long description of Egyptian zodiacs follows. At Dendera, the great temple portico faces north, its ceiling showing the zodiac in two bands embraced by a long female figure. The western band begins with the Lion marching north; the eastern runs opposite, beginning with Aquarius. The division falls between Lion and Cancer, or within the Crab itself. An inner hall held a circular planisphere brought to Paris by M. Lelorrain, where the signs form a somewhat spiral line, the Crab marching contrary to the others. At Esne, two temples have zodiacs; the great temple’s band presents the Lion, Scarabæus, Twins, Bull, Ram, and Fishes, while the small temple’s south band begins with the Lion preceded by the Scarabæus and Gemini. It was first thought the divisions fell between Virgin and Lion, but Mr Hamilton and MM. de Jollois and Villiers supposed the Sphinx preceding the Virgin repeats the Lion, placing the division there.

Main Arguments

The central argument of the essay is that the present state of the earth’s surface is the product of a series of revolutions, and that these revolutions were sudden rather than gradual. Cuvier argues that the sea, before the horizontal strata were deposited, had formed other strata that were broken, raised, and overturned in countless ways by problematical causes. Some inclined strata rise higher than the horizontal strata succeeding and surrounding them, proving that the causes of their inclination also made them project above sea level as islands, shoals, or inequalities. This is the second result, as clearly demonstrated as the first.

A second argument concerns the succession of living beings. Comparing strata and their animal remains shows that the ancient sea did not always deposit the same minerals or the same species, and that each deposit did not cover the whole surface. Older strata are more uniform over great extents; newer ones are more limited and variable. Aquatic animals changed with the strata: shells of ancient strata have peculiar forms and gradually disappear; recent strata shells resemble present-day genera; the latest, least consolidated strata contain species indistinguishable from neighbouring seas. A succession of variations in organic nature thus led aquatic classes to their present state; when the sea last retired from the continents, its inhabitants differed little from today’s.

A third argument concerns the suddenness of catastrophes. Most catastrophes were sudden, especially the last, which inundated and then laid dry the present continents. In northern regions it left carcases of large quadrupeds enveloped in ice, preserved with skin, hair, and flesh—impossible had they not frozen immediately upon death, and impossible had the eternal frost previously occupied those places, since the animals could not have lived in such temperatures. Thus animals were destroyed and their country covered with ice at one and the same moment—sudden, instantaneous, without gradation. The breaking, raising, and overturning of older strata likewise prove sudden, violent causes; heaps of debris and rounded pebbles between solid strata attest the force of motions in the waters. Life has often been disturbed by terrible events: land animals swallowed by inundations, aquatic ones laid dry by sudden elevation of the sea bottom; races extinguished forever, leaving only fragments scarcely recognizable.

A fourth argument is that life has not always existed on the globe. Ascending toward great ridges and craggy summits, marine remains become rarer and disappear; strata of different nature contain no vestiges of living beings. Their crystallization and stratification show they were liquid at formation; their inclined position and broken cliffs show forcible movement; their dipping under shelly strata shows they were formed earlier; their height above shelly strata shows their summits had emerged when shelly strata formed. These are the Primitive Mountains traversing continents, rising above clouds, separating river basins, feeding springs with perpetual snows, forming the Earth’s skeleton. Their indentations and sharp peaks indicate violent elevation, unlike rounded hills quietly deposited by more recent seas.

A fifth argument concerns the order of succession among quadrupeds. Almost all known bones of viviparous quadrupeds occur either in fresh-water formations or in alluvial formations, so the quadrupeds likely began to exist, or at least to leave remains in the strata, only after the last retreat of the sea but one and during the state preceding its last irruption. The bones also show an order among themselves, indicating a remarkable succession of species. All now-unknown genera, such as the Palæotheria and Anaplotheria, belong to the oldest of these formations, resting immediately on coarse limestone. The most celebrated unknown species belonging to known or closely allied genera—fossil elephants, rhinoceroses, hippopotami, and mastodons—do not occur with those more ancient genera. Bones of species apparently identical with living ones occur only in the last alluvial deposits on river sides, dried pool or marsh bottoms, peat beds, rock fissures and caverns, or at small depths where buried by debris or human hands.

A sixth argument addresses the objection that extinct species might be varieties of existing ones. Cuvier answers from the system of those who believe in indefinite alteration of organized forms: if species changed by degrees, traces of gradual modification should be found—intermediate forms between palæotheria and present species—yet none has ever been discovered. Why have the earth’s bowels not preserved monuments of so strange a genealogy, unless former species were as constant as ours, or the catastrophe destroying them left insufficient time for alleged variation? To reply to naturalists who acknowledge varieties are restrained within limits fixed by nature, one must examine how far these limits extend. Differences constituting variety depend on determinate circumstances and increase with their intensity. Most superficial characters vary most: colour depends on light, fur thickness on heat, size on abundance of food. In wild animals even these are greatly limited by natural habits. Cuvier compared skulls of foxes from northern countries and from Egypt with those of France, finding no difference beyond what might be expected in different individuals.

A seventh argument concerns the newness of the present continents as confirmed by the history of nations. Cuvier examines the traditions of nations and the evidence of monuments, and concludes that nature uniformly speaks the same language, everywhere informing us that the present order of things cannot have commenced at a very remote period. Remarkably, mankind everywhere speaks as nature, whether we consult received traditions of nations or examine the monuments they have left. The essay then dismantles the alleged astronomical proofs of extreme antiquity, showing that the zodiacs of Upper Egypt were sculptured when Egypt was subject to the Romans, and that the inferences drawn from them rest on a chain of uncertain suppositions.

Key Concepts

The concept of revolution is central to the essay. Cuvier uses the term to describe the sudden changes that have affected the earth’s surface and its inhabitants. These revolutions were not gradual processes but violent events: the breaking, raising, and overturning of strata, the irruption and retreat of waters, the extinction of races. The essay distinguishes between the slow, everyday causes that can be observed in operation—rivers raising their beds, the sea advancing on low coasts, downs overwhelming cultivated land—and the catastrophic causes that have left their mark in the geological record. The present order of things cannot have commenced at a very remote period, and the agents now at work, though real, are insufficient to explain the great features of the earth’s surface.

The concept of succession is equally important. Cuvier traces a sequence of organic forms from the primitive mountains, which contain no vestiges of living beings, through the transition rocks, where the first productions of mollusca and zoophytes appear, to the secondary formations, where reptiles reach full development, and finally to the alluvial deposits, where the bones of large quadrupeds are found. This succession is not merely a sequence of rock types but a sequence of living beings: the shells of ancient strata have peculiar forms and gradually disappear; recent strata shells resemble present-day genera; the latest strata contain species indistinguishable from neighbouring seas. Among quadrupeds, the oldest formations contain the Palæotheria and Anaplotheria; the alluvial formations contain fossil elephants, rhinoceroses, hippopotami, and mastodons; the most recent deposits contain species identical with living ones.

The concept of the problematical cause recurs throughout the essay. Cuvier uses this phrase to describe the forces responsible for the inclination, elevation, and overturning of strata—forces whose nature cannot be fully determined from the evidence available. He does not pretend to explain these causes; he insists only that the facts demonstrate their operation. This methodological restraint is one of the essay’s distinguishing features. Cuvier is willing to describe what has happened without claiming to know how it happened, and he criticizes those who substitute conjecture for observation.

The concept of the species and its limits is developed at length. Cuvier defines a species as individuals descending from each other or common parents, and those resembling them as much as they resemble each other. Varieties are races more or less different sprung from it by generation. Observations of differences between ancestors and descendants afford the only certain rule; all other considerations yield hypothetical conclusions without proof. Differences constituting variety depend on determinate circumstances and increase with their intensity. Most superficial characters vary most: colour depends on light, fur thickness on heat, size on abundance of food. In wild animals even these are greatly limited by natural habits. This analysis serves to show that the differences between fossil species and living species cannot be explained as mere varieties.

The concept of the natural chronometer appears in the later sections. Cuvier describes several processes whose rates can be measured and whose cumulative effects can be used to estimate the age of the present order of things. The alluvial deposits of the Po have advanced into the sea so rapidly that the shore has gained more than six thousand fathoms since 1604—an average of 150 to 180 feet yearly, and in places 200 feet. The downs or sand hillocks thrown up by the sea on low sandy coasts advance irresistibly upon the land; the late M. Bremontier estimated their progress at sixty feet yearly, in places seventy-two. The peat-mosses of northern Europe increase in height in determinate proportions for each place. These chronometers all point to the same conclusion: the present order of things cannot have commenced at a very remote period.

The concept of the monument and the document is also important. Cuvier treats geological formations as documents that can be read, and he treats ancient monuments as documents that must be interpreted with the same care. He warns against the tendency to read into monuments meanings that they do not bear, and he insists on the need to distinguish between authentic records and the productions of ignorance and superstition. The zodiacs of Upper Egypt, the lists of kings preserved by Manetho and Herodotus, the inscriptions on temples—all these are subjected to critical scrutiny, and the result is a radical reduction of the antiquity that had been claimed for them.

Themes

One of the essay’s deepest themes is the instability of the earth and its inhabitants. The reflection on fossil remains that stands near the opening sets the tone: fossil organic remains are relics of a primeval world, proclaiming the instability of earthly affairs and inspiring piety. The essay returns to this theme repeatedly. Life has often been disturbed by terrible events: land animals swallowed by inundations, aquatic ones laid dry by sudden elevation of the sea bottom; races extinguished forever, leaving only fragments scarcely recognizable. The present order of things is not permanent; it is the latest in a series of states, and it too will pass.

A second theme is the relationship between observation and speculation. Cuvier presents himself as a defender of careful observation against the builders of systems. He reviews the earlier systems of Leibnitz and Buffon, the more recent systems that revive Demaillet’s ideas, the vitalist cosmologies that treat the globe as a living body, and the pantheistic philosophies that reduce all phenomena to polarization. He catalogues the diversities of systems among more cautious geologists, and he asks why so much contrariety prevails among men proceeding on the same principles. His answer is that the conditions of the problem were never all taken into consideration at once, leaving it indeterminate and susceptible of many solutions. The essay’s method is to insist on the whole range of phenomena, and to refuse to abstract from inconvenient facts.

A third theme is the relationship between the history of the earth and the history of nations. Cuvier argues that the newness of the present continents is confirmed by the history of nations, and he examines the traditions of the Egyptians, the Indians, the Chinese, and the Babylonians. He finds that the alleged antiquity of these nations is not supported by the evidence. The Egyptian priests possessed no real history—inferior even to India’s, lacking connected fables—preserving only defective king-lists and confused remembrances of distinguished kings. The Chinese astronomers, though they kept registers of phenomena, did not know how to calculate shadows in 1629 of our era. The inferences drawn from alleged astronomical perfection among ancient nations do not support their excessive antiquity. The essay thus brings geology and history into a single frame, arguing that the evidence of the rocks and the evidence of the monuments point to the same conclusion.

A fourth theme is the relationship between science and piety. The reflection on fossil remains speaks of piety, and the essay as a whole is written in a spirit of reverence for the works of Nature. Cuvier does not present his conclusions as a threat to religion; on the contrary, he presents them as a demonstration of the instability of earthly affairs and a summons to piety. The essay’s tone is one of awe before the vastness of the changes that have occurred, and of humility before the limits of human knowledge. This combination of scientific rigor and moral seriousness is one of the book’s most distinctive features.

A fifth theme is the problem of extinction. Cuvier’s argument requires that species have been extinguished, and he returns to this point repeatedly. Races have been extinguished forever, leaving only fragments scarcely recognizable. The Palæotheria and Anaplotheria are unknown genera; the fossil elephants, rhinoceroses, hippopotami, and mastodons are unknown species; the ichthyosaurus, the plesiosaurus, the megalosaurus, and the pterodactyli are forms that no longer exist. The essay does not treat extinction as a problem to be explained away; it treats it as a fact to be established and its implications to be followed out. This is one of the ways in which the essay marks a departure from earlier natural history, which had often assumed that all species were still living somewhere on the globe.

The Author’s Conclusions

Cuvier’s conclusions are stated with a mixture of confidence and caution. He is confident that the facts demonstrate a succession of revolutions and a succession of organic forms. He is cautious about the causes of these revolutions, which he calls problematical, and about the precise intervals between them, which he says cannot be precisely defined. The essay ends not with a grand system but with a series of fixed points regulating inquiry into ancient chronology.

The first conclusion is that the present continents are new. Nature uniformly speaks the same language, everywhere informing us that the present order of things cannot have commenced at a very remote period. The natural chronometers—the alluvial deposits of rivers, the advance of the downs, the growth of peat-mosses—all point to the same conclusion. The history of nations confirms this: the traditions of the Egyptians, the Indians, the Chinese, and the Babylonians do not support the extreme antiquity that had been claimed for them. The zodiacs of Upper Egypt were sculptured when Egypt was subject to the Romans; the alleged astronomical proofs of national antiquity are dissipated.

The second conclusion is that there have been at least one and probably two successions in the class of quadrupeds before the present population of the earth’s surface. Cuvier remains satisfied that a comprehensive view of phenomena will lead others, as it led him, to conclude this. The oldest formations contain the Palæotheria and Anaplotheria; the alluvial formations contain fossil elephants, rhinoceroses, hippopotami, and mastodons; the most recent deposits contain species identical with living ones. The differences between these faunas cannot be explained as mere varieties, because no intermediate forms have been discovered, and because the limits of variation in wild animals are narrow.

The third conclusion is that the last catastrophe was sudden and recent. In northern regions it left carcases of large quadrupeds enveloped in ice, preserved with skin, hair, and flesh—impossible had they not frozen immediately upon death. Animals were destroyed and their country covered with ice at one and the same moment—sudden, instantaneous, without gradation. The breaking, raising, and overturning of older strata likewise prove sudden, violent causes. The present order of things began with a catastrophe, and the agents now at work, though real, are insufficient to explain the great features of the earth’s surface.

The fourth conclusion is that the causes of these revolutions are problematical. Cuvier does not pretend to explain them. He describes what has happened without claiming to know how it happened. This methodological restraint is itself a conclusion: the essay argues that the proper response to the evidence is not to construct a system but to establish the facts and to recognize the limits of our knowledge. The essay’s final movement is toward the appendix on the ibis, which brings the argument back to the natural history of a single species and its place in the ancient world. The book concludes with this return to the particular, after the vast sweep of its geological and historical argument.

Significance

The essay’s significance lies in several directions. For the history of geology, it represents a powerful statement of the catastrophic view of earth history, and a sustained critique of the speculative systems that had dominated the subject. Cuvier’s insistence on the suddenness of revolutions, on the succession of organic forms, and on the newness of the present continents shaped the terms of geological debate for decades. His use of natural chronometers—the alluvial deposits of rivers, the advance of the downs, the growth of peat-mosses—provided a model for estimating the age of the present order of things from observable processes.

For the history of natural history, the essay is a landmark in the study of fossil vertebrates.