 Preface to the ninth edition of Principles of Geology. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Larry Wilson. Principles of Geology by Charles Lyon. The Principles of Geology in the first five editions embraced not only a view of the modern changes of the earth and its inhabitants, as set forth in the present work, but also some account of those monuments of analogous changes of ancient date, both in the organic and inorganic world, which it is the business of the geologists to interpret. The subject last mentioned, or geology proper, constituted originally a fourth book, now omitted, the same having been enlarged into a separate treatise. First published in 1838 in one volume, 12 Do Decemo, and called the Elements of Geology. Afterwards, recast in two volumes, 12 Do Decemo, in 1842, and again re-edited under the title of Manual of Elementary Geology in one volume, 8 Octavo, in 1851. The Principles of Manual, thus divided, occupy with one exception to which I shall presently elude, very different ground. The Principles treat of such portions of the economy of existing nature, animate and inanimate, as are illustrative of geology, so as to comprise an investigation of the permanent effects of causes now in action, which may serve as records to after-ages of the present condition of the globe and its inhabitants. Such effects are the enduring monuments of the ever-varying state of the physical geography of the globe, the lasting signs of its destruction and renovation, and the memorials of the equally fluctuating condition of the organic world. They may be regarded in short as a symbolical language in which the Earth's autobiography is written. In the Manual of Elementary Geology, on the other hand, I have treated briefly of the component materials of the Earth's crust, their arrangement and relative position, and their organic contents, which, when deciphered by Adu-the-Keys supplied by the study of the modern changes above alluded to, reveal to us the annals of a grand succession of past events, a series of revolutions which the solid exterior of the globe and its living inhabitants have experienced in times antecedent to the creation of man. And thus separating the two works, however, I have retained the principles, Book One, the discussion of some matters which might fairly be regarded as common to both treatises. As, for example, an historical sketch of the early progress of geology, followed by a series of preliminary essays to explain the facts and arguments which lead me to believe that the forces now operating upon and beneath the Earth's surface may be the same, both in kind and degree, as those which at remote epochs have worked out geological changes. See analysis of contents of this work, Page 9. If I am asked whether the principles or the manual should be studied first, I feel much the same difficulty in answering the question as if a student should inquire whether he ought to take up first a treatise on chemistry or one on natural philosophy, subjects sufficiently distinct yet inseparably connected. On the whole, while I have endeavored to make each of the two treatises in their present form quite independent of the other, I would recommend the reader to study first the modern changes of the Earth and its inhabitants as they are discussed in the present volume, proceeding afterwards to the classification and interpretation of the monuments of more remote ages. Charles Lyle, 11 Harley Street, London, May 24th, 1853. End of Preface to the 9th edition of Principles of Geology. Chapter 1 of Principles of Geology. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Principles of Geology by Charles Lyle. Book 1, Chapter 1. Geology is the science which investigates the successive changes that have taken place in the organic and inorganic kingdoms of nature. It inquires into the causes of these changes and the influence which they have exerted in modifying the surface and external structure of our planet. By these researches into the state of the Earth and its inhabitants at former periods, we acquire a more perfect knowledge of its present condition and more comprehensive views concerning the laws now governing its animate and inanimate productions. When we study history, we obtain a more profound insight into human nature by instituting a comparison between the present and former states of society. We trace the long series of events which have gradually led to the actual posture of affairs, and by connecting effects with their causes, we are unable to classify and retain in the memory a multitude of complicated relations. The various peculiarities of national character, the different degrees of moral and intellectual refinement, and numerous other circumstances which, without historical associations, would be uninteresting or imperfectly understood. As the present condition of nations is the result of many antecedent changes, some extremely remote, and others recent, some gradual, others sudden and violent, so the state of the natural world is the result of a long succession of events, and if we would enlarge our experience of the present economy of nature, we must investigate the effects of her operations in former epics. We often discover with surprise, on looking back into the chronicles of nations, how the fortune of some battle has influenced the fate of millions of our contemporaries, when it has long been forgotten by the mass of the population. With this remote event, we may find inseparably connected the geographical boundaries of a great state, the language now spoken by the inhabitants, their peculiar manners, laws, and religious opinions. But far more astonishing and unexpected are the connections brought to light when we carry back our researches into the history of nature. The form of a coast, the configuration of the interior of a country, the existence and extent of lakes, valleys, and mountains can often be traced to the former prevalence of earthquakes and volcanoes in regions which have long been undisturbed. To these remote convulsions, the present fertility of some districts, the sterile character of others, the elevation of land above the sea, the climate, and various peculiarities may be distinctly referred. On the other hand, many distinguishing features of the surface may often be ascribed to the operation at a remote era of slow and tranquil causes to the gradual deposition of sediment in a lake or in the ocean, or to the prolific increase of testacea and corals. To select another example, we find in certain localities subterranean deposits of coal, consisting of vegetable matter formerly drifted into seas and lakes. These seas and lakes have since been filled up. The lands whereon the forest grew have disappeared or changed their form. The rivers and currents which floated the vegetable masses can no longer be traced, and the plants belong to species which for ages have passed away from the surface of our planet. Yet the commercial prosperity and numerical strength of a nation may now be mainly dependent on the local distribution of fuel determined by that ancient state of things. Geology is intimately related to almost all the physical sciences, as history is to the moral. An historian should, if possible, be at once profoundly acquainted with ethics, politics, jurisprudence, the military art, theology, in a word with all branches of knowledge by which any insight into human affairs or into the moral and intellectual nature of man can be obtained. It would be no less desirable that a geologist should be well versed in chemistry, natural philosophy, mineralogy, zoology, comparative anatomy, botany, in short, in every science relating to organic and inorganic nature. With these accomplishments, the historian and geologist would rarely fail to draw correct and philosophical conclusions from the various monuments transmitted to them of former occurrences. They would know to what combination of causes analogous effects were referable. They would often be enabled to supply, by inference, information concerning many events unrecorded in the defective archives of former ages. But as such extensive acquisitions are scarcely within the reach of any individual, it is necessary that men who have devoted their lives to different departments should unite their efforts. And as the historian receives assistance from the antiquary and from those who have cultivated different branches of moral and political science, so the geologist should avail himself of the aid of many naturalists, and particularly of those who have studied the fossil remains of lost species of animals and plants. The analogy, however, of the monuments consulted in geology and those available in history extends no farther than to one class of historical monuments, those which may be said to be undesignedly commemorative of former events. The canoes, for example, and stone hatchets found in our peat bogs afford an insight into the rude arts and manners of the earliest inhabitants of our island. The buried coin fixes the date of the reign of some Roman emperor. The ancient encampment indicates the districts once occupied by invading armies, and the former method of constructing military defenses. The Egyptian mummies throw light on the art of embalming, the rites of sepulcher, or the average stature of the human race in ancient Egypt. This class of memorials yields to no other in authenticity, but it constitutes a small part only of the resources on which the historian relies, whereas in geology it forms the only kind of evidence which is at our command. For this reason, we must not expect to obtain a full and connected account of any series of events beyond the reach of history, but the testimony of geological monuments, if frequently imperfect, possesses at least the advantage of being free from all intentional misrepresentation. We may be deceived in the inferences which we draw in the same manner as we often mistake the nature and import of phenomena observed in the daily course of nature, but our liability to err is confined to the interpretation, and if this be correct, our information is certain. It was long before the distinct nature and legitimate objects of geology were fully recognized, and it was at first confounded with many other branches of inquiry, such as the limits of history, poetry, and mythology were ill-defined in the infancy of civilization. Even in Werner's time, or at the close of the 18th century, geology appears to have been regarded as little other than a subordinate department of mineralogy, and Desma rest included it under the head of physical geography. But the most common and serious source of confusion arose from the notion that it was the business of geology to discover the mode in which the earth originated, or as some imagined, to study the effects of those cosmological causes which were employed by the author of Nature to bring this planet out of a nascent and chaotic state into a more perfect and habitable condition. Hutton was the first to endeavor to draw a strong line of demarcation between his favorite science and cosmogony, for he declared that geology was in no wise concerned, quote, with questions as to the origin of things, unquote. An attempt will be made in the sequel of this work to demonstrate that geology differs as widely from cosmogony as speculations concerning the mode of the first creation of man differ from history. But before entering more at large on this contraverted question, it will be desirable to trace the progress of opinion on this topic from the earliest ages to the commencement of the present century. Chapter 2. Historical Sketch of the Progress of Geology Oriental cosmogony, hymns of the Vedas, institutes of menu, doctrine of the successive destruction and renovation of the world, origin of this doctrine, common to the Egyptians adopted by the Greeks, system of Pythagoras of Aristotle, dogmas concerning the extinction and reproduction of genera and species, Strabo's theory of elevation by earthquakes, Pliny, concluding remarks on the knowledge of the ancients. Oriental cosmogony, the earliest doctrines of the Indian and Egyptian schools of philosophy agreed in ascribing the first creation of the world to an omnipotent and infinite being. They concurred also in representing this being who had existed from all eternity as having repeatedly destroyed and reproduced the world and all its inhabitants. In the sacred volume of the Hindus called the Ordinances of Menu, comprising the Indian system of duties, religious, and civil, we find a preliminary chapter treating of the creation in which the cosmogony is known to have been derived from earlier writings and traditions and principally from certain hymns of high antiquity called the Vedas. These hymns were first put together according to Mr. Colbrook in a connected series about 13 centuries before the Christian era, but they appear from internal evidence to have been written at various antecedent periods. In them, as we learn from the researches of Professor Wilson, the eminent Sanskrit scholar, two distinct philosophical systems are discoverable. According to one of them, all things were originally brought into existence by the sole will of a single first cause, which existed from eternity. According to the other, there have always existed two principles, the one material but without form, the other spiritual and capable of compelling, quote, inert matter to develop its sensible properties, end quote. This development of matter into, quote, individual and visible existences, end quote, is called creation and is assigned to a subordinate agent or the creative faculty of the supreme being embodied in the person of Brahma. In the first chapter of the ordinances of Menuh above alluded to, we meet with the following passages relating to former destructions and renovations of the world, quote, the being whose powers are incomprehensible, having created me, Menuh, and this universe again became absorbed in the supreme spirit, changing the time of energy for the hour of repose. When the power awakes, then has this world its full expansion, but when he slumbers with the tranquil spirit, then the whole system fades away. For while he reposes, as it were, embodied spirits endowed with principles of action, depart from their several acts, and the mind itself becomes inert, end quote. The absorption of all beings into the supreme essences then described, and the divine soul itself is said to slumber, and to remain for a time immersed in, quote, the first idea or in darkness, end quote. After which the text thus proceeds, verse 57, quote, thus that immutable power by waking and reposing alternatively revivifies and destroys in eternal succession this whole assemblage of locomotive and immovable creatures, end quote. It is then declared that there has been a long succession of Manwantaras, or periods, each of the duration of many thousand ages, end quote. There are creations also and destructions of worlds innumerable. The being supremely exalted performs all this with as much ease as if in sport, again and again for the sake of conferring happiness, end quote. No part of the eastern cosmogony from which these extracts are made is more interesting to the geologist than the doctrine so frequently alluded to of the reiterated submersion of the land beneath the waters of a universal ocean. In the beginning of things we are told the first sole cause, quote, with a thought created the waters, end quote, and then moved upon their surface in the form of Brahma the Creator, by whose agency the emergence of the dry land was affected and the peopling of the earth with plants, animals, celestial creatures, and man. Afterwards, as often as a general conflagration at the close of each Manwantara had annihilated every visible and existing thing, Brahma, unawakening from his sleep, finds the whole world a shapeless ocean. Accordingly, in the legendary poems called the Puranas, composed at a later date than the Vedas, the three first avatars or descents of the deity upon earth have for their object to recover the land from the waters. For this purpose Vishnu is made successively to assume the form of a fish, a tortoise, and a boar. Extravagant as may be some of the conceits and fictions which disfigure these pretended revelations, we can by no means look upon them as a pure effort of the unassisted imagination or believe them to have been composed without regard to opinions and theories founded on the observation of nature. In astronomy, for instance, it is declared that at the North Pole the year was divided into a long day and night, and that their long day was the northern and their night the southern course of the sun, and to the inhabitants of the moon it is said one day is equal in length to one month of mortals. If such statements cannot be resolved into mere conjectures, we have no right to refer to mere chance, the prevailing notion that the earth and its inhabitants had formerly undergone a succession of revolutions and aqueous catastrophes interrupted by long intervals of tranquility. Now there are two sources in which such a theory may have originated. The marks of former convulsions on every part of the surface of our planet are obvious and striking. The remains of marine animals embedded in the solid strata are so abundant that they may be expected to force themselves on the attention of every people who have made some progress in refinement, and especially where one class of men are expressly set apart from the rest, like the ancient priesthoods of India and Egypt, for study in contemplation. If these appearances are once recognized, it seems natural that the mind should conclude in favor not only of mighty changes in past ages, but of alternate periods of repose and disorder. Of repose when the animals now fossil, lived, grew, and multiplied of disorder when the strata in which they were buried becomes transferred from the sea to the interior of continents and were uplifted so as to form part of high mountain chains. Those modern writers who are disposed to disparage the former intellectual advancement and civilization of eastern nations may concede some foundation of observed facts for the curious theories now under consideration without indulging in exaggerated opinions of the progress of science, especially as universal catastrophes of the world and exterminations of organic beings in the sense in which they were understood by the Brahmins are untenable doctrines. We know that the Egyptian priests were aware not only that the soil beneath the planes of the Nile, but that also the hills bounding the Great Valley contained marine shells, and Herodotus inferred from these facts that all lower Egypt and even the high lands above Memphis had once been covered by the sea. As similar fossil remains occur in all parts of Asia, hitherto explored, far in the interior of the continent, as well as near the sea, they could hardly have escaped detection by some eastern sages not less capable than the Greek historian of reasoning philosophically on natural phenomena. We also know that the rulers of Asia were engaged in very remote areas in executing great national works such as tanks and canals requiring extensive excavations. In the 14th century of our era, in the year 1360, the removal of soil necessary for such undertakings brought to light geological facts which attracted the attention of a people less civilized than were many of the older nations of the East. The historian Ferishta relates that 50,000 laborers were employed in cutting through a mound so as to form a junction between the rivers Selima and Sutlej. And in this mound were found the bones of elephants and men, some of them petrified and some of them resembling bone. The gigantic dimensions attributed to the human bones show them to have belonged to some of the larger Pachy Dermata. But although the Brahmins, like the priests of Egypt, may have been acquainted with the existence of fossil remains in the strata, it is possible that the doctrine of successive destructions and renovations of the world merely received corroboration from such proofs and that it may have been originally handed down, like the religious traditions of most nations, from a ruder state of society. The system may have had its source, in part at least in exaggerated accounts of those dreadful catastrophes which are occasioned by particular combinations of natural causes. Floods and volcanic eruptions, the agency of water and fire, are the chief instruments of devastation on our globe. We shall point out in the sequel the extent of many of these calamities recurring at distant intervals of time in the present course of nature, and shall only observe here that they are so peculiarly calculated to inspire a lasting terror and are so often fatal in their consequences to great multitudes of people, that it scarcely requires the passion for the marvelous, so characteristic of rude and half civilized nations, still less the exuberant imagination of Eastern writers to augment them into general cataclysms and conflagrations. The great flood of the Chinese, which their traditions carry back to the period of Ya'u, something more than 2,000 years before our era, has been identified by some persons with the universal deluge described in the Old Testament. But according to Mr. Davis, who accompanied two of our embassies to China and who has carefully examined their written accounts, the Chinese cataclysm is therein described as interrupting the business of agriculture rather than as involving a general destruction of the human race. The great Yu was celebrated for having, quote, opened nine channels to draw off the waters, end quote, which, quote, covered the low hills and bathed the foot of the highest mountains, end quote. Mr. Davis suggests that a great derangement of waters of the Yellow River, one of the largest in the world, might even now cause the flood of Ya'u to be repeated and lay the most fertile and populous plains of China under water. In modern times, the bursting of the banks of an artificial canal into which a portion of the Yellow River has been turned has repeatedly given rise to the most dreadful accidents and is a source of perpetual anxiety to the government. It is easy, therefore, to imagine how much greater may have been the inundation if this valley was ever convulsed by a violent earthquake. Humboldt relates the interesting fact that after the annihilation of a large part of the inhabitants of Kumana by an earthquake in 1766, a season of extraordinary fertility ensued in consequence of the great rains which accompanied the subterranean convulsions. The Indians, he says, celebrated after the ideas of an antique superstition by festivals and dancing, the destruction of the world, and the approaching epoch of its regeneration. The existence of such rites among the rude nations of South America is most important as showing what effects may be produced by local catastrophes recurring at distant intervals of time on the minds of a barbarous and uncultivated race. I shall point out in the sequel how the tradition of a deluge among the Arawkanian Indians may be explained by reference to great earthquake waves which have repeatedly rolled over part of Chile since the first recorded flood of 1590. The legend also of the ancient Peruvians of an inundation many years before the reign of the Incas in which only six persons were saved on a float relates to a region which has more than once been overwhelmed by inroads of the ocean since the days of Pizarro. I might refer the reader to my account of the submergence of a wide area in Cuch so lately as the year 1819 when a single tower only of the Fort of Sindri appeared above the waist of waters. If it were necessary to prove how easily the Catachphes of modern times might give rise to traditionary narratives among a rude people of floods of boundless extent. Nations without written records and who are indebted for all their knowledge of past events exclusively to oral tradition are in the habit of confounding in one legend a series of incidents which have happened at various epochs nor must we forget that the superstitions of a savage tribe are transmitted through all the progressive stages of society till they exert a powerful influence on the mind of the philosopher. He may find in the monuments of former changes on the earth's surface an apparent confirmation of tenets handed down through successive generations from the rude hunter whose terrified imagination drew a false picture of those awful visitations of floods and earthquakes whereby the whole earth as known to him was simultaneously devastated. Egyptian cosmogony. Respecting the cosmogony of the Egyptian priests we gather much information from writers of the Grecian sects who borrowed almost all their tenets from Egypt and amongst others that of the former successive destruction and renovation of the world. We learn from Plutarch that this was the theme of the hymns of Orpheus so celebrated in the fabulous ages of Greece. It was brought to him from the banks of the Nile and we even find in his verses as in the Indian systems a definite period assigned for the duration of each successive world. The returns of great catastrophes were determined by the period of the anus magnus or great year. A cycle composed of the revolutions of the sun, moon, and planets and terminating when these returned together to the same sign whence they were supposed at some remote epoch to have set out. The duration of this great cycle was variously estimated. According to Orpheus it was 120,000 years. According to others 300,000 and by Cassander it was taken to be 360,000 years. We learn particularly from the Timaeus of Plato that the Egyptians believed the world to be subject to occasional conflagrations and deluges whereby the gods rested the career of human wickedness and purified the earth from guilt. After each regeneration mankind were in a state of virtue and happiness from which they gradually degenerated again into vice and immorality. From this Egyptian doctrine the poets derived the fable of the decline from the golden to the iron age. The sect of Stoics adopted most fully the system of catastrophes destined at certain intervals to destroy the world. Those they taught were of two kinds the cataclysm or destruction by water which sweeps away the whole human race and annihilates all the animal and vegetable productions of nature and the echpirosis or destruction by fire which dissolves the globe itself. From the Egyptians also they derived the doctrine of the gradual debasement of man from a state of innocence. Towards the termination of each era the gods could no longer bear with the wickedness of men and a shock of the elements or a deluge overwhelmed them after which calamity astrea again descended on the earth to renew the golden age. The connection between the doctrine of successive catastrophes and repeated deteriorations in the moral character of the human race is more intimate and natural than might at first be imagined. Four in a rude state of society all great calamities are regarded by the people as judgments of God on the wickedness of man. Thus in our own time the priests persuaded a large part of the population of Chile and perhaps believed themselves that the fatal earthquake of 1822 was a sign of the wrath of heaven for the great political revolution just then consummated in South America. In like manner in the account given to Solon by the Egyptian priests of the submersion of the island of Atlantis under the waters of the ocean after repeated shocks of an earthquake we find that the event happened when Jupiter had seen the moral depravity of the inhabitants. Now when the notion had once gained ground whether from causes before suggested or not that the earth had been destroyed by several general catastrophes it would next be inferred that the human race had been as often destroyed and renovated. And since every extermination was assumed to be penal it could only be reconciled with divine justice by the supposition that man at each successive creation was regenerated in a state of purity and innocence. A very large portion of Asia inhabited by the earliest nations whose traditions have come down to us has been always subject to tremendous earthquakes. Of the geographical boundaries of these and their effects I shall speak in the proper place. Egypt has for the most part been exempt from this scourge and the Egyptian doctrine of great catastrophes was probably derived in part as before hinted from early geological observations and in part from eastern nations. End of chapter 2 part 1. Recording by Patrick McAfee, Chicago. Chapter 2 part 2 of Principles of Geology. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer please visit LibriVox.org. Recording by Patrick McAfee, Chicago. Principles of Geology by Charles Lyell. Chapter 2 part 2. Pythagorean doctrines. Pythagoras who resided for more than 20 years in Egypt and according to Cicero had visited the east and conversed with the Persian philosophers introduced into his own country on his return the doctrine of the gradual deterioration of the human race from an original state of virtue and happiness but if we are to judge of his theory concerning the destruction and renovation of the earth from the sketch given by Ovid we must concede it to have been far more philosophical than any known version of the cosmogonies of Oriental or Egyptian sex. Although Pythagoras is introduced by the poet as delivering his doctrine in person, some of the illustrations are derived from natural events which happened after the death of the philosopher. But notwithstanding these anachronisms we may regard the account as a true picture of the tenets of the Pythagorean school in the Augustan age and although perhaps partially modified it must have contained the substance of the original scheme. Thus considered it is extremely curious and instructive for we here find a comprehensive summary of almost all the great causes of change now in activity on the globe and these adduced in confirmation of a principle of a perpetual and gradual revolution inherent in the nature of our terrestrial system. These doctrines it is true are not directly applied to the explanation of geological phenomena or in other words no attempt is made to estimate what may have been in past ages or what may hereafter be the aggregate amount of change brought about by such never-ending fluctuations. Had this been the case we might have been called upon to admire so extraordinary an anticipation with no less interest than astronomers when they endeavour to define by what means the Sammian philosopher came to the knowledge of the Compertingen system. Let us now examine the celebrated passages to which we have been adverting. Nothing perishes in this world but things merely vary and change their form. To be born means simply that a thing begins to be something different from what it was before and dying is ceasing to be the same thing. Yet although nothing retains long the same image the sum of the whole remains constant. These general propositions are then confirmed by a series of examples all derived from natural appearances except the first which refers to the golden age giving place to the age of iron. The illustrations are thus consecutively adduced. 1. Solid land has been converted into sea. 2. Sea has been changed into land. Marine shells lie far distant from the deep and the anchor has been found on the summit of hills. 3. Valleys have been excavated by running water and floods have washed down hills into the sea. 4. Marshes have become dry ground. 5. Dry lands have been changed into stagnant pools. 6. During earthquakes some springs have been closed up and new ones have broken out. Rivers have deserted their channels and have been reborn elsewhere as the Erasinus in Greece and Mises in Asia. 7. The waters of some rivers formerly sweet have become bitter as those of the Onigree in Greece etc. 8. Islands have become connected with the mainland by the growth of deltas and new deposits as in the case of Antissa joined to Lesbos, Theros to Egypt etc. 9. Peninsulas have been divided from the mainland and have become islands as Lucadia and according to tradition Sicily the sea having carried away the Isthmus. 10. Land has been submerged by earthquakes. The Grecian cities of Helis and Buris for example are to be seen under the sea with their walls inclined. 11. Plains have been upheaved into hills by the confined air seeking vent as at Trezin in the Peloponnesus. 12. The temperature of some springs varies at different periods. The waters of others are inflammable. 13. There are streams which have a petrifying power and convert the substances which they touch into marble. 14. Extraordinary medicinal and deleterious effects are produced by the water of different lakes and springs. 15. Some rocks and islands after floating and having been subject to violent movements have at length become stationary and immovable as Delos and the Cyanian Isles. 16. Volcanic vents shift their position. There was a time when Etna was not a burning mountain and the time will come when it will cease to burn whether it be that some caverns become closed up by the movements of the earth and others opened or whether the fuel is finally exhausted etc etc. The various causes of change in the inanimate world having been thus enumerated the doctrine of equivocal generation is next propounded as illustrating a corresponding perpetual flux in the animate creation. In the Egyptian and Eastern cosmogonies and in the Greek version of them no very definite meaning can in general be attached to the term destruction of the world for sometimes it would seem almost to imply the annihilation of our planetary system and at others a mere revolution of the surface of the earth. 16. Opinions of Aristotle From the works now excellent of Aristotle and from the system of Pythagoras as above exposed we might certainly infer that these philosophers considered the agents of change now operating in nature as capable of bringing about in the lapse of ages a complete revolution and the stagurite even considers occasional catastrophes happening at distant intervals of time as part of the regular and ordinary course of nature. The deluge of Ducalian he says affected Greece only and principally the part called Helas and it arose from great inundations of rivers during a rainy winter but such extraordinary winters he says though after a certain period they return do not always revisit the same places. Censorinas quotes it as Aristotle's opinion that there were general inundations of the globe and that they alternated with conflagrations and that the flood constituted the winter of the great year or astronomical cycle while the conflagration or destruction by fire is the summer or period of greatest heat. If this passage as Lipsius supposes be an amplification by Censorinas of what is written in the meteorics it is a gross misrepresentation of the doctrine of the stagurite for the general bearing of his reasoning in that treatise tends clearly in an opposite direction. He refers to many examples of changes now constantly going on and insists emphatically on the great results which they must produce in the lapse of ages. He instances particular cases of lakes that had dried up and deserts that had at length become watered by rivers and fertilized. He points to the growth of the Nealotic Delta since the time of Homer to the shallowing of the Palus Metos within 60 years from his own time and although in the same chapter he says nothing of earthquakes yet in others of the same treatise he shows himself not unacquainted with their effects. He alludes for example to the upheaving of one of the Aeolian islands previous to a volcanic eruption. Quote the changes of the earth he says are so slow in comparison to the duration of our lives that they are overlooked and the migrations of people after great catastrophes and the removal to other regions cause the event to be forgotten. End quote. When we consider the acquaintance displayed by Aristotle in his various works with the destroying and renovating powers of nature the introductory and concluding passages of the twelfth chapter of his meteorics are certainly very remarkable. In the first sentence he says quote the distribution of land and sea in particular regions does not endure throughout all time but it becomes sea in those parts where it was land and again it becomes land where it was sea and there is reason for thinking that these changes take place according to a certain system and within a certain period. End quote. The concluding observation is as follows quote as time never fails and the universe is eternal neither the Taneas nor the Nile can have flowed forever. The places where they rise were once dry and there is a limit to their operations but there is none to time. So also of all other rivers they spring up and they perish and the sea also continually deserts some lands and invades others. The same tracts therefore of the earth are not some always sea and others always continents but everything changes in the course of time. End quote. It seems then that the Greeks had not only derived from preceding nations but had also in some slight degree deduced from their own observations the theory of periodical revolutions in the inorganic world. There is however no ground for imagining that they contemplated former changes in the races of animals and plants. Even the fact that marine remains were enclosed in solid rocks although observed by some and even made the groundwork of geological speculation never stimulated the industry or guided the inquiries of naturalists. It is not impossible that the theory of equivocal generation might have engendered some indifference on this subject and that a belief in the spontaneous production of living beings from the earth or corrupt matter might have caused the organic world to appear so unstable and fluctuating that phenomena indicative of former changes would not awaken intense curiosity. The Egyptians it is true had taught and the Stoics had repeated that the earth had once given birth to some monstrous animals which existed no longer but the prevailing opinion seems to have been that after each great catastrophe the same species of animals were created over again. This tenet is implied in a passage of Seneca where speaking of a future deluge he says quote every animal shall be generated anew and man free from guilt shall be given to the earth end quote. An old Arabian version of the doctrine of the successive revolutions of the globe translated by Abraham echelensis seems to form a singular exception to the general rule for here we find the idea of different genera and species having been created. The Germanites a sect of astronomers who flourished some centuries before the Christian era taught as follows quote that every period of 36,425 years there were produced a pair of every species of animal both male and female from whom animals might be propagated and inhabit this lower world but when a circulation of the heavenly orbs was completed which is finished in that space of years other genera and species of animals are propagated as also of plants and other things and the first order is destroyed and so it goes on forever and ever end quote. Theory of Strabo as we learn much of the tenets of the Egyptian and Oriental schools in the writings of the Greeks so many speculations of the early Greek authors are made known to us in the works of the Augustan and later ages Strabo in particular enters largely in the second book of his geography into the opinions of Eratosthenes and other Greeks on one of the most difficult problems in geology this by what causes marine shells came to be plentifully buried in the earth at such great elevations and distances from the sea he notices amongst others the explanation of Xanthus the Lydian who said that the seas had once been more extensive and that they had afterwards been partially dried up as in his own time many lakes rivers and wells in Asia had failed during a season of drought treating this conjecture with merited disregard Strabo passes on to the hypothesis of Straito the natural philosopher who had observed that the quantity of mud brought down by rivers into the Uxene was so great that its bed must be gradually raised while the rivers still continue to pour in an undiminished quantity of water he therefore conceived that originally when the Uxene was an inland sea its level had by this means become so much elevated that it burst its barrier near Byzantium and formed a communication with the propontus and this partial drainage he supposed had already converted the left side into marshy ground and thus at last the hole would be choked up with soil so it was argued the Mediterranean had once opened a passage for itself by the columns of Hercules into the Atlantic and perhaps the abundance of seashells in Africa near the temple of Jupiter Ammon might also be the deposit of some former inland sea which had at length forced a passage and escaped but Strabo rejects this theory as insufficient to account for all the phenomena and he proposes one of his own the profoundness of which modern geologists are only beginning to appreciate quote it is not he says because the lands were covered by seas were originally at different altitudes that the waters have risen or subsided or receded from some parts and inundated others but the reason is that the same land is sometimes raised up and sometimes depressed and the sea also is simultaneously raised and depressed so that it either overflows or returns into its own place again we must therefore ascribe the cause to the ground either to that ground which is under the sea or to that which becomes flooded by it but rather to that which lies beneath the sea for this is more movable and on account of its humidity can be altered with great celerity it is proper he observes in continuation to derive our explanations from things which are obvious and in some measure of daily occurrence such as deluges earthquakes and volcanic eruptions and sudden swellings of the land beneath the sea for the last raise up the sea also and when the same lands subside again they occasion the sea to be let down and it is not merely the small but the large islands also and not merely the islands but the continents which can be lifted up together with the sea and both large and small tracks may subside for habitations and cities like Bure, Bisona, and many others have been engulfed by earthquakes in another place this learned geographer in alluding to the tradition that Sicily had been separated by a convulsion from Italy remarks that at present the land near the sea in those parts was rarely shaken by earthquakes since there were now open orifices whereby fire and ignited matters and waters escape but formerly when the volcanoes of Etna the Lippari islands Isia and others were closed up the imprisoned fire and wind might have produced far more vehement movements the doctrine therefore that volcanoes are safety valves and that the subterranean convulsions are probably most violent when first the volcanic energy shifts itself to a new quarter is not modern we learn from a passage in Strabo that it was a dogma of the gallish druids that the universe was immortal but destined to survive catastrophes both of fire and water that this doctrine was communicated to them from the east with much of their learning cannot be doubted Caesar it will be remembered says that they made use of Greek letters in earth medical computations Pliny this philosopher had no theoretical opinions of his own concerning changes of the earth's surface and in this department as in others he restricted himself to the task of a compiler without reasoning on the facts stated by him or attempting to digest them into regular order but his enumeration of the new islands which had been formed in the Mediterranean and of other convulsions shows that the ancients had not been inattentive observers of the changes which had taken place within the memory of man such then appears to have been the opinions entertained before the Christian era concerning the past revolutions of our globe although no particular investigations had been made for the express purpose of interpreting the monuments of ancient changes they were too obvious to be entirely disregarded and the observation of the present course of nature presented too many proofs of alterations continually in progress on the earth to allow philosophers to believe that nature was in a state of rest or that the surface had remained and would continue to remain unaltered but they had never compared attentively the results of the destroying and reproductive operations of modern times with those of remote eras nor had they ever entertained so much as a conjecture concerning the comparative antiquity of the human race or of living species of animals and plants with those belonging to former conditions of the organic world they had studied the movements and positions of the heavenly bodies with laborious industry and made some progress in investigating the animal vegetable and mineral kingdoms but the ancient history of the globe was to them a sealed book and although written in characters of the most striking and imposing kind they were unconscious even of its existence end of chapter 2 part 2 recording by patrick mccaffey chicago chapter 3 part 1 of principles of geology this is a liberovox recording a liberovox recordings are in the public domain for more information or to volunteer please visit liberovox.org recording by dion giants salt lake city utah principles of geology by charles lial chapter 3 arabian writers of the 10th century avicenna omar cosmogony of the caran casuini early italian writers leonardo da vinci fracostoro controversy as to the real nature of fossils attributed to the mosaic deluge policy steno sila carini boil lister leibniz hoax theory of elevation by earthquakes of lost species of animals ray physical theological writers woodwords deluvial theory bernette houston valis nary lazaro moro generally buffon his theory condemned by the sarban as unorthodox his declaration targioni arduino michel catcott raspe fuchel fortis testa whitehurst palace sasur arabian writers after the decline of the roman empire the cultivation of physical science was first revived with some success by the saracens about the middle of the eighth century of our era the works of the most eminent classic writers were purchased at great expense from the christians and translated into arabic and al mamoon son of the famous haroon al-rashid the contemporary of charlemagne received with marks of distinction at his court at bagdad astronomers and men of learning from different countries this caliph and some of his successors encountered much opposition and jealousy from the doctors of the muhammad and law who wished the muslims to confine their studies to the quran dreading the effects of the diffusion of a taste for the physical sciences avesena almost all the works of the early arabian writers are lost amongst those of the tenth century of which fragments are now extant is a short treatise on the formation and classification of minerals by avesena a physician in whose arrangement there is considerable merit the second chapter on the cause of mountains is remarkable for mountains he says are formed some by essential others by accidental causes in illustration of the essential he instances of violent earthquake by which land is elevated and becomes a mountain of the accidental the principle he says is excavation by water whereby cavities are produced and adjoining lands made to stand out and form eminences omar cosmogony of the quran in the same century also omar surnamed l alam or the learned wrote a work on the retreat of the sea it appears that on comparing the charts of his own time with those made by the indian and persian astronomers two thousand years before he had satisfied himself that important changes had taken place since the times of history in the form of the coasts of asia and that the extension of the sea had been greater at some former periods he was confirmed in this opinion by the numerous salt springs and marshes in the interior of asia a phenomenon from which palace in more recent times has drawn the same inference von hoff has suggested with great probability that the changes in the level of the caspian some of which there is reason to believe have happened within the historical era and the geological appearances in that district indicating the desertion by that sea of its ancient bed had probably led omar to his theory of a general subsidence but whatever may have been the proofs relied on his system was declared contradictory to certain passages in the quran and he was called upon publicly to recant his errors to avoid which persecution he went into voluntary banishment from samarkand the cosmological opinions expressed in the quran are few and merely introduced incidentally so that it is not easy to understand how they could have interfered so seriously with free discussion on the former changes of the globe the prophet declares that the earth was created in two days and the mountains were then placed on it and during these and two additional days the inhabitants of the earth were formed and in two more the seven heavens there is no more detail of circumstances and the deluge which is also mentioned is discussed with equal brevity the waters are represented to have poured out of an oven a strange fable said to be borrowed from the persian magi who represented them as issuing from the oven of an old woman all men were drowned save noah and his family and then god said oh earth swallow up thy waters and thou oh heaven withhold thy reign and immediately the waters abated we may suppose omar to have represented the desertion of the land by the sea to have been gradual and that his hypothesis required a greater lapse of ages than was consistent with muslim orthodoxy for it is to be inferred from the quran that man and this planet were created at the same time and although muhammad did not limit expressly the antiquity of the human race yet he gave an implied sanction to the mosaic chronology by the veneration expressed by him for the hebrew patriarchs a manuscript work entitled the wonders of nature is preserved in the royal library at paris by an arabian writer muhammad kazweeni who flourished in the seventh century of the hegera or at the close of the 13th century of our era besides several curious remarks on arolytes earthquakes and the successive changes of position which the land and sea have undergone we meet with the following beautiful passage which is given as the narrative of keyed's an allegorical personage i passed one day by a very ancient and wonderfully populous city and asked one of its inhabitants how long it had been founded it is indeed a mighty city replied he we know not how long it has existed and our ancestors were on this subject as ignorant as ourselves five centuries afterwards as i passed by the same place i could not perceive the slightest vestige of the city i demanded of a peasant who was gathering herbs upon its former site how long it had been destroyed in soothe a strange question replied he the ground here has never been different from what you now behold it was there not of old said i a splendid city here never answered he so far as we have seen and never did our father speak to us of any such on my return there 500 years afterwards i found the sea in the same place and on its shores were a party of fishermen of whom i inquired how long the land had been covered by the waters is this a question said they for a man like you this spot has always been what it is now i again returned 500 years afterwards and the sea had disappeared i inquired of a man who stood alone upon the spot how long ago this change had taken place and he gave me the same answer as i had received before lastly on coming back again after an equal lapse of time i found there a flourishing city more populous and more rich in beautiful buildings than the city i had seen the first time and when i would feign have informed myself concerning its origin the inhabitants answered me its rise is lost in remote antiquity we are ignorant how long it has existed and our fathers were on this subject as ignorant as ourselves early italian writers it was not till the earlier part of the 16th century that geological phenomenon began to attract the attention of the christian nations at that period a very animated controversy sprang up in italy concerning the true nature and origin of marine shells and other organized fossils found abundantly in the strata of the peninsula the celebrated painter Leonardo da Vinci who in his youth had planned and executed some navigable canals in the north of italy was one of the first who applied sound reasoning to these subjects the mud of rivers he said had covered and penetrated into the interior of fossil shells at a time when these were still at the bottom of the sea near the coast they tell us that these shells were formed in the hills by the influence of the stars but i ask where in the hills are the stars now forming shells of distinct ages and species and how can the stars explain the origin of gravel occurring at different heights and composed of pebbles rounded as if by the motion of running water or in what manner can such a cause account for the petrification in the same places of various leaves seaweeds and marine crabs the excavations made in 1517 for repairing the city of Verona brought to light a multitude of curious petrifications and furnished matter for speculation to different authors and among the rest two fracostoro who declared his opinion that fossil shells had all belonged to living animals which had formerly lived and multiplied where their exuvia are now found he exposed the absurdity of having recourse to a certain plastic force which it was said had power to fashion stones into organic forms and with no less cogent arguments demonstrated the futility of attributing the situation of the shells in question to the mosaic deluge a theory obstinately defended by some that inundation he observed was too transient it consisted principally of fluvia tile waters and if it had transported shells to great distances must have strewed them over the surface not buried them at vast depths in the interior of mountains his clear exposition of the evidence would have terminated the discussion forever if the passions of mankind had not been enlisted in the dispute and even though doubts should for a time have remained in some minds they would speedily have been removed by the fresh information obtained almost immediately afterwards respecting the structure of fossil remains and of their living analogues but the clear and philosophical views of fracostoro were disregarded and the talent and argumentative powers of the learned were doomed for three centuries to be wasted in the discussion of these two simple and preliminary questions first whether fossil remains had ever belonged to living creatures and secondly whether if this be admitted all the phenomena could not be explained by the deluge of noa it had been the general belief of the christian world down to the period now under consideration that the origin of this planet was not more remote than a few thousand years and that since the creation the deluge was the only great catastrophe by which considerable change had been wrought on the earth's surface on the other hand the opinion was scarcely less general that the final dissolution of our system was an event to be looked for at no distant period the era it is true of the expected millennium had passed away and for 500 years after the fatal hour when the annihilation of the planet had been looked for the monks remained in undisturbed enjoyment of rich grants of land bequeathed to them by pious donors who in the preamble of deeds beginning a propin quantae mundi termino a propin quantae magno judici dia left lasting monuments of the popular delusion but although in the 16th century it had become necessary to interpret certain prophecies respecting the millennium more liberally and to assign a more distant date to the future conflagration of the world we find in the speculation of the early geologists perpetual illusion to such an approaching catastrophe while in all that regarded the antiquity of the earth no modification whatever of the opinions of the dark ages had been affected considerable alarm was at first excited when the attempt was made to invalidate by physical proofs an article of faith so generally received but there was sufficient spirit of toleration and candor amongst the italian ecclesiastics to allow the subject to be canvassed with much freedom they even entered warmly into the controversy themselves often favoring different sides of the question and however much we may deplore the loss of time and labor devoted to the defense of untenable positions it must be conceded that they displayed far less polemic bitterness than certain writers who followed them beyond the alps two centuries and a half later end of chapter three part one chapter three part two of principles of geology this is a liberovox recording all liberovox recordings are in the public domain for more information or to volunteer please visit liberovox.org recording by dion giants salt lake city utah principles of geology by charles liel chapter three part two controversy as to the real nature of fossil organic remains mariole volopio the system of scholastic disputations encouraged in the universities of the middle ages had unfortunately trained men to habits of indefinite argumentation and they often preferred absurd and extravagant propositions because greater skill was required to maintain them the end and object of these intellectual combats being victory and not truth no theory could be so far-fetched or fantastical as not to attract some followers provided it fell in with popular notions and as cosmogeness were not at all restricted in building their systems to the agency of known causes the opponents of frost coutureau met his arguments by feigning imaginary causes which differed from each other rather in name than in substance andria madioli for instance and eminent botanists the illustrator of diaz scordais embraced the notion of agri-cola a skillful german miner that a certain materials pinguas or fatty matter set into fermentation by heat gave birth to fossil organic shapes yet madioli had come to the conclusion from his own observations that porous bodies such as bones and shells might be converted into stone as being permeable to what he termed the lapidifying juice in like manner falapio of padua conceived that petrified shells were generated by fermentation in the spots where they are found or that they had in some cases acquired their form from the tumultuous movements of terrestrial exhalations although celebrated as a professor of anatomy he taught that certain tasks of elephants dug up in his time in apulia were mere earthly concretions and consistently with these principles he even went so far as to consider it probable that the vases of monta tesca seo at rome were natural impressions stamped in the soil in the same spirit mercati who published in 1574 faithful figures of the fossil shells preserved by pope sixth as the fifth in the museum of the vatican expressed an opinion that they were mere stones which had assumed their peculiar configuration from the influence of the heavenly bodies and olivia of cremona who described the fossil remains of a rich museum at vorona was satisfied with considering them as mere sports of nature some of the fanciful notions of those times were deemed less unreasonable as being somewhat in harmony with the Aristotelian theory of spontaneous generation then taught in all the schools for men who had been taught in early youth that a large proportion of living animals and plants were formed from the fortuitous concourse of atoms or had sprung from the corruption of organic matter might easily persuade themselves that organic shapes often imperfectly preserved in the interior of solid rock owed their existence to causes equally obscure and mysterious cardano 1552 but there were not wanting some who during the progress of this century expressed more sound and sober opinions the title of a work of cardanos published in 1552 they subtelitate corresponding to what would now be called transcendental philosophy would lead us to expect in the chapter on minerals many far-fetched theories characteristic of that age but when treating of petrified shells he decided that they clearly indicated the former sojourn of the sea upon the mountains sassopino majoli 1597 sassopino a celebrated botanist conceived that fossil shells had been left on the land by the retiring sea and had concreted into stone during the consolidation of the soil and in the following year 1597 simion majoli went still farther and coinciding for the most part with the views of sassopino suggested that the shells and submarine matter of the varanese and other districts might have been cast up upon the land by volcanic explosions like those which gave rise in 1538 to monta nova near puzzoli this hint seems to have been the first imperfect attempt to connect the position of fossil shells with the agency of volcanoes a system afterwards more fully developed by hook lezaro moro hutton and other writers two years afterwards emperati advocated the animal origin of fossilized shells yet admitted that stones could vegetate by force of an internal principle and as evidence of this he referred to the teeth of fish and spines of akini found petrified policy 1580 policy of french writer on the origin of springs from rainwater and of other scientific works undertook in 1580 to combat the notions of many of his contemporaries in italy that petrified shells had all been deposited by the universal deluge he was the first said fontanel when in the french academy he pronounced his eulogy nearly a century and a half later who dared assert in paris that fossil remains of testicia and fish had once belonged to marine animals fabio colonna to enumerate the multitude of italian writers who advanced various hypotheses all equally fantastical in the early part of the 17th century would be unprofitably tedious but fabio colonna deserves to be distinguished for although he gave way to the dogma that all fossil remains were to be referred to the deluge of noa he resisted the absurd theory of stiluti who taught that fossil wood and ammonites were mere clay altered into such forms by sulfurious waters and subterranean heat and he pointed out the different states of shells buried in the strata distinguishing between first the mere mold or impression second the cast or nucleus and thirdly the remains of the shell itself he had also the merit of being the first to point out that some of the fossils had belonged to marine and some to terrestrial testicia steno 1669 but the most remarkable work of that period was published by steno adane once professor of anatomy at padua and who afterwards resided many years at the court of the grand duke of tuscany his treatise bears the quaint title of desolido intransolidum natural tier contento 1669 by which the author intended to express on gems crystals and organic petrifications enclosed within solid rocks this work attests the priority of the italian school in geological research exemplifying at the same time the powerful obstacles opposed in that age to the general reception of enlarged views in the science it was still a favorite dogma that the fossil remains of shells and marine creatures were not of animal origin an opinion adhered to by many from their extreme reluctance to believe that the earth could have been inhabited by living beings before a great part of the existing mountains were formed in reference to this controversy steno had dissected a shark recently taken from the mediterranean and had demonstrated that its teeth and bones were identical with many fossils found in tuscany he had also compared the shells discovered in the italian strata with living species pointed out their resemblance and traced the various gradations from shells merely calcined or which had only lost their animal gluten to those petrifications in which there was a perfect substitution of stony matter in his division of mineral masses he insisted on the secondary origin of those deposits in which the spoils of animals or fragments of older rocks were enclosed he distinguished between marine formations and those of a fluvia tile character the last containing reeds grasses or the trunks and branches of trees he argued in favor of the original horizontality of sedimentary deposits attributing their present inclined and vertical position sometimes to the escape of subterranean vapors heaving the crust of the earth from below upwards and sometimes to the falling in of masses overlying subterranean cavities he declared that he had obtained proof that tuscany must successively have acquired six distinct configurations having been twice covered by water twice laid dry with a level and twice with an irregular and uneven surface he displayed great anxiety to reconcile his new views with scripture for which purpose he pointed to certain rocks as having been formed before the existence of animals and plants selecting unfortunately as examples certain formations of limestone and sandstone in his own country now known to contain those sparingly the remains of animals and plants strata which do not even rank as the oldest part of our secondary series steno suggested that moses when speaking of the loftiest mountains as having been covered by the deluge meant merely the loftiest of the hills then existing which may not have been very high the diluvian waters he supposed may have issued from the interior of the earth into which they had retired when in the beginning the land was separated from the sea these and other hypotheses on the same subject are not calculated to enhance the value of the treatise and could scarcely fail to detract from the authority of those opinions which were sound and legitimate deductions from fact and observation they have served nevertheless as the germs of many popular theories of later times and in an expanded form have been put forth as original inventions by some of our contemporaries Silla 1670 Silla a Sicilian painter published in 1670 a treatise in Latin on the fossils of Calabria illustrated by good engravings this work proves the continued ascendancy of dogmas often refuted for we find the wit and eloquence of the author chiefly directed against the obstinate incredulity of naturalists as to the organic nature of fossil shells like many eminent naturalists of his day Silla gave way to the popular persuasion that all fossil shells were the effects and proofs of the mosaic deluge it may be doubted whether he was perfectly sincere and some of his contemporaries who took the same course were certainly not so but so eager were they to root out what they justly considered and absurd prejudice respecting the nature of organized fossils that they seem to have been ready to make any concessions in order to establish this preliminary point such a compromising policy was short sighted since it was too little purpose that the nature of the documents should at length be correctly understood if men were to be prevented from deducing fair conclusions from them deluvial theory the theologians who now entered the field in Italy Germany France and England were innumerable and hence forward they who refused to subscribe to the position that all marine organic remains were proofs of the mosaic deluge were exposed to the imputation of disbelieving the whole of the sacred writings scarcely any step had been made in approximating two sound theories since the time of frost Gatoro more than a hundred years having been lost in writing down the dogma that organized fossils were mere sports of nature an additional period of a century and a half was now destined to be consumed in exploding the hypothesis that organized fossils had all been buried in the solid strata by Noah's flood never did a theoretical fallacy in any branch of science interfere more seriously with accurate observation and the systematic classification of facts in recent times we may attribute our rapid progress chiefly to the careful determination of the order of succession in mineral masses by means of their different organic contents and their regular superposition but the old deluvialists were induced by their system to confound all the groups of strata together instead of discriminating to refer all appearances to one cause and to one brief period not to a variety of causes acting throughout a long succession of epochs they saw the phenomena only as they desired to see them sometimes misrepresenting facts and at other times deducing false conclusions from correct data under the influences of such prejudices three centuries were of as little avail as a few years in our own times when we are no longer required to propel the vessel against the force of an adverse current it may be well therefore to forewarn the reader that in tracing the history of geology from the close of the 17th to the end of the 18th century he must expect to be occupied with accounts of the retardation as well as of the advance of the science it will be necessary to point out the frequent revival of exploded errors and the relapse from sound to the most absurd opinions and to dwell on feudal reasoning and visionary hypothesis because some of the most extravagant systems were invented or controverted by men of acknowledged talent in short a sketch of the progress of geology is the history of a constant and violent struggle of new opinions against doctrines sanctioned by the implicit faith of many generations and supposed to rest on scriptural authority the inquiry therefore although highly interesting to one who studies the philosophy of the human mind is too often barren of instruction to him who searches for truths in physical science querini 1676 querini in 1676 contended in opposition to silla that the diluvian waters could not have conveyed heavy bodies to the summit of mountains since the agitation of the sea never as boil had demonstrated extended to great depths and still less could the testicia as some pretended have lived in these diluvian waters for the duration of the flood was brief and the heavy rains must have destroyed the saltness of the sea he was the first writer who ventured to maintain that the universality of the mosaic cataclysm ought not to be insisted upon as to the nature of petrified shells he conceived that as earthly particles united in the sea to form the shells of molusca the same crystallizing process might be affected on the land and that in the latter case the germs of the animals might have been disseminated through the substance of the rocks and afterwards developed by virtue of humidity visionary as was this doctrine it gained many proselytites even amongst the more sober reasoners of italy and germany for it conceded that the position of fossil bodies could not be accounted for by the diluvial theory plot lister 1678 in the meantime the doctrine that fossil shells had never belonged to real animals maintained its ground in england where the agitation of the question began at a much later period doctor plot in his natural history of oxfordshire 1677 attributed to a plastic virtue latent in the earth the origin of fossil shells and fishes and lister to his accurate account of british shells in 1678 added the fossil species under the appellation of turbinated and bivalve stones either said he these were terigenous or if otherwise the animals they so exactly represent have become extinct this writer appears to have been the first who was aware of the continuity over large districts of the principal groups of strata in the british series and who proposed the construction of regular geological maps leibniz 1680 the great mathematician leibniz published his protagia in 1680 he imagined this planet to have been originally a burning luminous mass which ever since its creation has been undergoing refrigeration when the outer crust had cooled down sufficiently to allow the vapors to be condensed they fell and formed a universal ocean covering the loftiest mountains and investing the whole globe the crust as it consolidated from a state of fusion assumed a vascular and cavernous structure and being rent in some places allowed the water to rush into the subterranean hollows whereby the level of the primeval ocean was lowered the breaking in of these vast caverns is supposed to have given rise to the dislocated and deranged position of the strata which stenow had described and the same disruptions communicated violent movements to the incumbent waters whence great inundations ensued the waters after they had been thus agitated deposited their sedimentary matter during intervals of quiescence and hence the various stony and earthy strata we may recognize therefore says leibniz a double origin of primitive masses the one by refrigeration from igneous fusion the other by concretion from aqueous solution by the repetition of similar causes the disruption of the crust and consequent floods alternations of new strata were produced until at length these causes were reduced to a condition of quiescent equilibrium and a more permanent state of things was established end of chapter three part two