 CHAPTER VIII. PART ONE. ON FORMER CHANGES IN PHYSICAL GEOGRAPHY AND CLIMATE Geographical features of the northern hemisphere at the period of the oldest fossiliferous strata. State of the surface when the mountain limestone and coal were deposited. Changes in physical geography between the Carbinoferris period and the Chalk. Abrupt transition from the secondary to the tertiary fossils. Descending of land and elevation of mountain chains after the consolidation of the secondary rocks. Explanation of map showing the area covered by sea since the commencement of the tertiary period. Astronomical theories of the causes of variations in climate. Theory of the diminution of the supposed primitive heat of the globe. In the sixth chapter I stated the arguments derived from organic remains for concluding that in the period when the Carbinoferris strata were deposited, the temperature of the ocean and the air was more uniform in the different seasons of the year and in different latitudes than at present, and that there was a remarkable absence of cold as well as great moisture in the atmosphere. It was also shown that the climate had been modified more than once since that epoch and that it had been reduced by successive changes, more and more nearly to that now prevailing in the same latitudes. Father, I endeavored in the last chapter to prove that vicissitudes in climate of no less importance may be expected to recur in future, if it be admitted that causes now active in nature have power in the laps of ages to produce considerable variations in the relative position of land and sea. It remains to inquire whether the alterations, which the geologist can prove to have actually taken place at former periods in the geographical features of the northern hemisphere coincide in their nature and in the time of their occurrence with such revolutions in climate as might naturally have resulted according to the meteorological principles already explained. Period of the primary fossiliferous rocks. The oldest system of strata which afford by their organic remains any evidence as to climate or the former position of land and sea are those formerly known as the transition rocks or what have since been termed lower Silurian or primary fossiliferous formations. These have been found in England, France, Germany, Sweden, Russia and other parts of Central and Northern Europe as also in the Great Lake District of Canada and the United States. The multi-locular or chambered univalves including the nautilus and the corals obtained from the limestones of these ancient groups have been compared to forms now most largely developed in tropical seas. The corals however have been shown by Mr. Milne Edwards to differ generally from all living zoophytes, so that conclusions as to a warmer climate drawn from such remote analogies must be received with caution. Hitherto few, if any, contemporaneous vegetable remains have been noticed, but such as I mentioned agree more nearly with the plants of the carboniferous era than any other and would therefore imply a warm and humid atmosphere entirely free from intense cold throughout the year. This absence or great scarcity of plants as well as of freshwater shells and other indications of neighboring land, coupled with the wide extent of marine strata of this age in Europe and North America, are facts which imply such a state of physical geography, so far at least as regards the northern hemisphere, as would, according to the principles before explained, give rise to such a moist and equitable climate. Carboniferous group. This group comes next in the order of succession and one of its principal members, the mountain limestone, was evidently a marine formation, as is shown by the shells and corals which it contains. That the ocean of that period was of considerable extent in our latitudes we may infer from the continuity of these calcareous strata over large areas in Europe, Canada and the United States. The same group has also been traced in North America towards the borders of the Arctic sea. There are also several regions in Scotland and in the central and northern parts of England as well as in the United States, where marine carboniferous limestones alternate with strata containing coal in such a manner as to imply the drifting down of plants by rivers into the sea and the alternate occupation of the same space by fresh and salt water. Since the time of the earlier writers, no strata have been more extensively investigated, both in Europe and North America than those of the ancient carboniferous group, and the progress of science has led to a general belief that a large portion of the purest coal has been formed, not as was once imagined by vegetable matter floated from a distance, but by plants which grew on the spot, and somewhat in the manner of peat on the spaces now covered by the beds of coal. The former existence of land in some of these spaces has been proved, as already stated, by the occurrence of numerous upright fossil trees, with their roots terminating downwards in seams of coal, and still more generally by the roots of trees, Stigmarier, remaining in their natural position in the clays which underlie almost every layer of coal. As some nearly continuous beds of such coal have of late years been traced in North America over areas one hundred or two hundred miles and upwards in diameter, it may be asked whether the large tracts of ancient land implied by this fact are not inconsistent with the hypothesis of the general prevalence of islands at the period under consideration. In reply, I may observe that the coal fields must originally have been low alluvial grounds, resembling in situation the cypress swamps of the Mississippi or the Sunderbunds of the Ganges, being liable like them to be inundated at certain periods by a river or by the sea if the land should be depressed a few feet. All the phenomena, organic and inorganic, imply conditions nowhere to be met with except in the deltas of large rivers. We have to account for an abundant supply of flu-viotile sediment carried for ages towards one and the same region and capable of forming strata of mud and sand thousands of feet or even fathoms in thickness, many of them consisting of laminated shale, enclosing the leaves of ferns and other terrestrial plants. We have also to explain the frequent intercalations of root beds and the interposition here and there of brackish and marine deposits, demonstrating the occasional presence of the neighboring sea. But these forest-covered deltas could only have been formed at the termination of large hydrographical basins, each drained by a great river and its tributaries, and the accumulation of sediment bears testimony to contemporaneous denudation on a large scale, and therefore to a wide area of land, probably containing within it one or more mountain chains. In the case of the Great Ohio or Appalachian Coal Field, the largest in the world, it seems clear that the uplands drained by one or more great rivers were chiefly to the eastward, or they occupied a space now filled by part of the Atlantic Ocean, for the mechanical deposits of mud and sand increased greatly in thickness and coarseness of material as we approach the eastern borders of the Coal Field, or the southeast flanks of the Allegani Mountains near Philadelphia. In that region, numerous beds of pebbles, often of the size of a hen's egg, are seen to alternate with beds of pure coal. But the American Coal Fields are all comprised within the 30th and 50th degrees of North latitude, and there is no reason to presume that the lands at the borders of which they originated ever penetrated so far or in such masses into the colder and arctic regions, so as to generate a cold climate. In the southern hemisphere, where the predominance of sea over land is now the distinguishing geographical feature, we nevertheless find a large part of the continent of Australia as well as New Zealand, placed between the 30th and 50th degrees of southern latitude. The two islands of New Zealand taken together are between 800 and 900 miles in length, with a breadth in some parts of 90 miles, and they stretch as far south as the 46th degree of latitude. They afford, therefore, a wide area for the growth of a terrestrial vegetation, and the botany of this region is characterized by abundance of ferns, 140 species of which are already known, some of them attaining the size of trees. In this respect, the southern shores of New Zealand in the 46th degree of latitude almost by with tropical islands. Another point of resemblance between the flora of New Zealand and that of the ancient Carbinoferus period is the prevalence of the fur tribe or of coniferous wood. An argument of some weight in corroboration of the theory above explained, respecting the geographical condition of the temperate and arctic latitudes of the northern hemisphere in the Carbinoferus period, may also be derived from an examination of those groups of strata which immediately preceded the Coal. The fossils of the Devonian and Silurian strata in Europe and North America have led to the conclusion that they were formed for the most part in deep seas far from land. In those older strata, land plants are almost as rare as they are abundant or universal in the Coal measures. Those ancient deposits, therefore, may be supposed to have belonged to an epoch when dry land had only just begun to be upraised from the deep, a theory which would imply the existence during the Carbinoferus epoch of islands instead of an extensive continent in the area where the Coal was formed. Such a state of things prevailing in the north, from the pole to the 30th parallel of latitude, if not neutralized by circumstances of a contrary tendency in corresponding regions south of the line, would give rise to a general warmth and uniformity of climate throughout the globe. Changes in physical geography between the formation of the Carbinoferus strata and the troch. We have evidence in England that the strata of the ancient Carbinoferus group, already adverted to, were in many instances fractured and contorted and often thrown into a vertical position before the deposition of some even of the oldest known secondary rocks such as the new red sandstone. Fragments of the older formations are sometimes included in the conglomerates of the more modern and some of these fragments still retain their fossil shells and corals, so as to enable us to determine the parent rocks from whence they were derived. There are other proofs of the disturbance at successive epochs of different secondary rocks before the deposition of others, and satisfactory evidence that, during these reiterated convulsions, the geographical features of the northern hemisphere were frequently modified, and that from time to time new lands emerged from the deep. The vegetation, during some parts of the period in question, from the liais to the troch inclusive, when De Nera allied to Sykes and Zemia were abundant, appears to have approached to that of the larger islands of the equatorial zone, such, for example, as we now find in the West Indian Archipelago. These islands appear to have been drained by rivers of considerable size, which were inhabited by crocodiles and gigantic oviparas reptiles, both herbivorous and carnivorous, belonging for the most part to extinct De Nera. Of the contemporary inhabitants of the land, we have as yet acquired but scanty information, but we know that there were flying reptiles, insects and small mammifers, allied to the marsupial tribes. A freshwater deposit, called the Wielden, occurs in the upper part of the secondary series of the south of England, which, by its extent and fossils, attests the existence in that region of a large river draining a continent or island of considerable dimensions. We know that this land was clothed with wood and inhabited by huge terrestrial reptiles and birds. Its position so far to the north as the counties of Surrey and Sussex, at a time when the mean temperature of the climate is supposed to have been much hotter than at present, may at first sight appear inconsistent with the theory before explained that the heat was caused by the gathering together of all the great masses of land in low latitudes, while the northern regions were almost entirely sea. But it must not be taken for granted that the geographical conditions already described as capable of producing the extreme of heat wherever combined at any geological period of which we have yet to obtain the information. It is more probable, from what has been stated in the preceding chapters, that a slight approximation to such an extreme state of things would be sufficient. In other words, if most of the dry land were tropical, and scarcely any of it arctic or Antarctic, a prodigious elevation of temperature must ensue, even though a part of some continents should penetrate far into the temperate zones. Changes during the tertiary periods. The secondary and tertiary formations of Europe, when considered separately, may be contrasted as having very different characters. The secondary appearing to have been deposited in open seas. The tertiary in regions were dry land, lakes, bays, and perhaps inland seas, abounded. The secondary series is almost exclusively marine. The tertiary, even the oldest part, contains lacustrine strata, and not unfrequently freshwater and marine beds alternating. In fact, there is evidence of important geographical changes, having occurred between the deposition of the Cretaceous system, or uppermost of the secondary series, and that of the oldest tertiary group, and still more between the era of the latter and that of the newer tertiary formations. This change in the physical geography of Europe and North America was accompanied by an alteration no less remarkable in organic life, scarcely any species being common both to the secondary and tertiary rocks, and the fossils of the latter affording evidence of a different climate. On the other hand, when we compare the tertiary formations of successive ages, we trace a gradual approximation in the embedded fossils from an assemblage in which extinct species predominate, to one where the species agree for the most part with those now existing. In other words, we find a gradual increase of animals and plants fitted for our present climates, in proportion as the strata which we examine are more modern. Now, during all these successive tertiary periods, there are signs of a great increase of land in European and North American latitudes. By reference to the map and its description, page 121, the reader will see that about two-thirds of the present European lands have emerged since the earliest tertiary group originated. Nor is this the only revolution which the same region has undergone within the period alluded to. Some tracts which were previously land have gained in altitude, others on the contrary having sunk below their former level. That the existing lands were not all upheaved at once into their present position is proved by the most striking evidence. Several Italian geologists, even before the time of Brocchi, had justly inferred that the Apennines were elevated several thousand feet above the level of the Mediterranean before the deposition of the modern sub-Apennine beds which flanked them on either side. What now constitutes the central calciferous chain of the Apennines must for a long time have been a narrow, ridgy peninsula branching off at its northern extremity from the Alps near Savona. This peninsula has since been raised from one to two thousand feet, by which movement the ancient shores and for a certain extent the bed of the contiguous sea have been laid dry, both on the side of the Mediterranean and the Adriatic. The nature of these vicissitudes will be explained by the accompanying diagram which represents a transverse section across the Italian peninsula. The inclined strata capital A are the disturbed formations of the Apennines into which the ancient igneous rocks A are supposed to have intruded themselves. At a lower level on each flank of the chain are the more recent Shelley beds B, which often contain rounded pebbles derived from the waste of contiguous parts of the older Apennine limestone. These it will be seen are horizontal and lie in what is termed uncomfortable stratification on the more ancient series. They now constitute a line of hills of moderate elevation between the sea and the Apennines, but never penetrate to the higher and more ancient valleys of that chain. The same phenomena are exhibited in the Alps on a much grander scale. Those mountains being composed in some even of their higher regions of the newer secondary and oldest tertiary formations, while they are encircled by a great zone of more modern tertiary rocks, both on their southern flanks towards the plains of the Poe and on the side of Switzerland and Austria, and at their eastern termination towards Styria and Hungary. This newer tertiary zone marks the position of former seas or gulfs, like the Adriatic, wherein masses of strata accumulated, some single groups of which are not inferior in thickness to the most voluminous of our secondary formations in England. Some even of these newer groups have been raised to the height of three or four thousand feet, and in proportion to their antiquity they generally rise to greater heights, the older of them forming interior zones nearest to the central ridges of the Alps. We have already ascertained that the Alps gained accessions to their height and width at several successive periods, and that the last series of improvements occurred when the seas were inhabited by many existing species of animals. We may imagine some future series of convulsions once more to heave up this stupendous chain, together with the adjoining bed of the sea, so that the mountains of Europe may rival the Andes in elevation, in which case the deltas of the Poe, Adice and the Brenta, now encroaching upon the Adriatic, might be uplifted, so as to form another exterior belt of considerable height around the south-eastern flank of the Alps. The Pyrenees also have acquired their present altitude, which in Mont-Perdue exceeds eleven thousand feet, since the deposition of the Namaltic or Eocene division of the tertiary series. Some of the tertiary strata at the base of the chain are raised to the height of only a few hundred feet above the sea, and retain a horizontal position without partaking in general in the disturbance to which the older series has been subjected, so that the great barrier between France and Spain was almost entirely upheaved in the interval between the deposition of certain groups of tertiary strata. The remarkable break between the most modern of the known secondary rocks and the oldest tertiary may be apparent only, and ascribable to the present deficiency of our information. Already the mulls and green sand of hairs near Tongre in Belgium, observed by Monsieur Dumont, and the piezolytic limestone of the neighborhood of Paris, both intermediate in age between the Maastricht-Torque and the lower Eocene strata, begin to afford us signs of a passage from one state of things to another. Nevertheless, it is far from impossible that the interval between the chalk and tertiary formations constituted an era in the Earth's history, when the transition from one class of organic beings to another was, comparatively speaking, rapid. For if the doctrines above explained in regard to vicissitudes of temperature are sound, it will follow that changes of equal magnitude in the geographical features of the globe may at different periods produce very unequal effects on climate, and so far as the existence of certain animals and plants depends on climate, the duration of species would be shortened or protracted according to the rate at which the change of temperature proceeded. For even if we assume that the intensity of the subterranean disturbing forces is uniform and capable of producing nearly equal amounts of alteration on the surface of the planet during equal periods of time, still the rate of alteration in climate would be by no means uniform. Let us imagine the quantity of land between the equator and the tropic in one hemisphere to be to that in the other as 13 to 1, which as before stated, represents the unequal proportion of the extra tropical lands in the two hemispheres at present. Then, let the first geographical change consist in the shifting of this preponderance of land from one side of the line to the other from the southern hemisphere for example to the northern. Now this need not affect the general temperature of the earth. But if, at another epoch, we suppose a continuance of the same agency to transfer an equal volume of land from the torrid zone to the temperate and arctic regions of the northern and southern hemispheres or into one of them, there might be so great a refrigeration of the mean temperature in all latitudes that scarcely any of the pre-existing races of animals would survive. And, unless it pleased the author of nature that the planet should be uninhabited, new species and probably of widely different forms would then be substituted in the room of the extinct. We ought not, therefore, to infer that equal periods of time are always attended by an equal amount of change in organic life. Since a great fluctuation in the mean temperature of the earth, the most influential cause which can be conceived in exterminating whole races of animals and plants must, in different epochs, require unequal proportions of time for its completion. This map will enable the reader to perceive at a glance the great extent of change in the physical geography of Europe which can be proved to have taken place since some of the older tertiary strata began to be deposited. The proofs of submergence, during some part or other of this period, in all the districts distinguished by ruled lines, are of a most unequivocal character, for the area thus described is now covered by deposits containing the fossil remains of animals which could only have lived in salt water. The most ancient part of the period referred to cannot be deemed very remote, considered geologically, because the deposits of the Paris and London basins and many other districts belonging to the older tertiary epoch are newer than the greater part of the sedimentary rocks, those commonly called secondary and primary for syliferous or paleozoic, of which the crust of the globe is composed. The species, moreover, of marine testesia, of which the remains are found in these older tertiary formations, are not entirely distinct from such as now live. Yet, notwithstanding the comparatively recent epoch to which this retrospect is carried, the variations in the distribution of land and sea depicted on the map form only a part of those which must have taken place during the period under consideration. Some approximation has merely been made to an estimate of the amount of sea converted into land in parts of Europe best known to geologists, but we cannot determine how much land has become sea during the same period, and there may have been repeated interchanges of land and water in the same places, changes of which no account is taken in the map, and respecting the amount of which little accurate information can ever be obtained. I have extended the sea in some instances beyond the limits of the land now covered by tertiary formations and marine drift, because other geological data have been obtained for inferring the submergence of these tracts after the deposition of the Eocene strata had begun. Thus, for example, there are good reasons for concluding that part of the Chalk of England, the North and South Downs, for example, together with the intervening secondary tracts, continued beneath the sea until the oldest tertiary beds had begun to accumulate. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. A Strait of the Sea separating England and Wales has also been introduced, on the evidence afforded by shells of existing species found in the deposit of gravel, sand, loam and clay, called the Northern Drift, by Sir R. Murchison. And Mr. Trimmer has discovered similar recent marine shells on the northern coast of north Wales, and on Moyle Trefun near the Menai Straits at the height of 1,392 feet above the level of the sea. Some raised sea beaches and drift containing marine shells, which I examined in 1843 between Limerick and Dublin, and which have been traced over other parts of Ireland by different geologists, have required an extension of the dark lines so as to divide that island into several. In improving this part of my map, I have been especially indebted to the assistance of Mr. Oldham, who in 1843 announced to the British Association at Cork the fact that at the period when the drift or glacial beds were deposited, Ireland must have formed an archipelago, such as is here depicted. A considerable part of Scotland might also have been represented in a similar manner as underwater when the drift originated. A portion of Brittany is divided into islands because it is known to be covered with patches of marine tertiary strata chiefly Myocene. When I examined these in 1830 and 1843, I convinced myself that the sea must have covered much larger areas than are now occupied by these small and detached deposits. The former connection of the White Sea and the Gulf of Finland is proved by the fact that a multitude of huge erratic blocks extend over the intervening space, and a large portion of Norway, Sweden and Denmark, as well as Germany and Russia, are represented as sea on the same evidence, strengthened by the actual occurrence of fossil seashells of recent species in the drift of various portions of those countries. The submergence of considerable areas under large bodies of fresh water during the tertiary period, of which there are many striking geological proofs in Auverne and elsewhere, has not been expressed by ruled lines. They bear testimony to the former existence of neighboring lands and a certain elevation of the areas where they occur above the level of the ocean. They are therefore a left plank, together with all the space that cannot be demonstrated to have been part of the sea at some time or other since the commencement of the Eocene epoch. In compiling this map, which has been entirely recast since the first edition, I have availed myself of the latest geological maps of the British Isles and North of Europe, and of those published by the government surveyors of France, Messieurs de Beaumont and Dufres Noir, the map of Germany and part of Europe by von Dechen and that of Italy by Messieurs Tihacov. Lastly, Sir R. Murchison's important map of Russia and the enjoying countries has enabled me to mark out not only a considerable area, previously little known, in which tertiary formations occur, but also a still wider expanse over which the northern drift and erratic blocks with occasional marine shells are traceable. The southern limits of these glacial deposits in Russia and Germany indicate the boundary, so far as we can now determine it, of the northern ocean at a period immediately antecedent to that of the human race. I was anxious, even in the title of this map, to guard the reader against the supposition that it was intended to represent the state of the physical geography of part of Europe at any one point of time. The difficulty, or rather the impossibility, of restoring the geography of the globe as it may have existed at any former period, especially a remote one, consists in this, that we can only point out where part of the sea has been turned into land and are almost always unable to determine what land may have become sea. All maps, therefore, pretending to represent the geography of remote geological epochs, must be ideal. The map under consideration is not a restoration of a former state of things at any particular moment of time, but a synoptical view of a certain amount of one kind of change, the conversion of sea into land, known to have been brought about within a given period. It may be proper to remark that the vertical movements to which the land is subject in certain regions occasion alternately the subsidence and the uprising of the surface, and that, by such oscillations at successive periods, a great area may have been entirely covered with marine deposits, although the whole may never have been beneath the waters at one time, nay, even though the relative proportion of land and sea may have continued unaltered throughout the whole period. I believe, however, that since the commencement of the tertiary period, the dry land in the northern hemisphere has been continually on the increase, both because it is now greatly in excess beyond the average proportion which land generally bears to water on the globe, and because a comparison of the secondary and tertiary strata affords indications, as I have already shown, of a passage from the condition of an ocean interspersed with islands to that of a large continent. But supposing it were possible to represent all the vicissitudes in the distribution of land and sea that have occurred during the tertiary period, and to exhibit not only the actual existence of land where there was once sea, but also the extent of surface now submerged which may once have been land, the map would still fail to express all the important revolutions in physical geography which have taken place within the epoch under consideration. For the oscillations of level, as was before stated, have not merely been such as to lift up the land from below the water, but in some cases to occasion arise of many thousand feet above the sea. Thus the Alps have acquired an additional altitude of 4,000 and even in some places 10,000 feet, and the Apennines owe a considerable part of their present height to subterranean convulsions which have happened within the tertiary epoch. On the other hand, some mountain chains may have been lowered during the same series of ages in an equal degree, and shoals may have been converted into deep abysses. Since this map was recast in 1847, geologists have very generally come to the conclusion that the pneumolytic limestone, together with the overlying focoidal grit and shale, called flish in the Alps, belongs to the older tertiary or eocene group. As these pneumolytic rocks enter into the structure of some of the most lofty and disturbed parts of the Alps, Apennines, Carpatians, Pyrenees and other mountain chains, and form many of the elevated lands of Africa and Asia, their position almost implies the ubiquity of the post-eocene ocean, not indeed by the simultaneous but by the successive occupancy of the whole ground by its waters. Concluding remarks on changes in physical geography. The foregoing observations, it may be said, are confined chiefly to Europe, and therefore merely established the increase of dry land in a space which constitutes but a small portion of the northern hemisphere. But it was stated in the preceding chapter that the great low land of Siberia, lying chiefly between the latitudes 55 degrees and 75 degrees north, an area nearly equal to all Europe, is covered for the most part by marine strata, which, from the account given by Pallas, and more recently by Sir R. Murchison, belongs to a period when all, or nearly all, the shells were of a species still living in the north. The emergence, therefore, of this area from the deep is, comparatively speaking, a very modern event, and must, as before remarked, have caused a great increase in coal throughout the globe. Upon a review then of all the facts above enumerated, respecting the ancient geography of the globe as attested by geological monuments, there appear good grounds for inferring that changes of climate coincided with remarkable revolutions in the former position of sea and land. A wide expanse of ocean, interspersed with islands, seems to have pervaded the northern hemisphere at the periods when the Silurian and Carbinoferus rocks were formed, and a warm and very uniform temperature then prevailed. Subsequent modifications in climate accompanied the deposition of the secondary formations, when repeated changes were effected in the physical geography of our northern latitudes. Lastly, the refrigeration became most decided, and the climate most nearly assimilated to that now enjoyed, when the lands in Europe and northern Asia had attained their full extension, and the mountain chains their actual height. Soon after the first publication of this theory of climate, an objection was made by an anonymous German critic in 1833, that there are no geological proofs of the prevalence of any former period of a temperature lower than that now enjoyed. Whereas, if the causes above assigned were the true ones, it might reasonably have been expected that fossil remains would sometimes indicate colder as well as hotter climates than those now established. In answer to this objection, I may suggest that our present climates are probably far more distant from the extreme of possible heat than from its opposite extreme of cold. A glance at the map will show that all the existing lands might be placed between the thirtieth parallels of latitude on each side of the equator, and that even then they would by no means feel that space. In no other position would they give rise to so high a temperature. But the present geographical condition of the earth is so far removed from such a state of things that the land lying between the poles and the parallels of thirty is in great excess. So much so that, instead of being to the sea in the proportion of one to three, which is as near as possible the average general ratio throughout the globe, it is nine to twenty-three. Hence it ought not to surprise us if, in our geological retrospect, embracing perhaps a small part only of a complete cycle of change in the terrestrial climates, we should happen to discover everywhere the signs of a higher temperature. The strata Hitherto examined may have originated when the quantity of equatorial land was always decreasing and the land in regions nearer the poles augmenting in height and area until at length it attained its present excess in high latitudes. There is nothing improbable in supposing that the geographical revolutions of which we have Hitherto obtained proofs had this general tendency, and in that case the refrigeration must have been constant, although for reasons before explained the rate of cooling may not have been uniform. It may, however, be as well to recall the reader's attention to what was before said of the indication brought to light of late years of a considerable oscillation of temperature in the period immediately preceding the human era. We have seen that on examining some of the most northern deposits, those commonly called the Northern Drift in Scotland, Ireland and Canada, in which nearly all, in some cases perhaps all, the fossil shells are of recent species, we discover the signs of a climate colder than that now prevailing in corresponding latitudes on both sides the Atlantic. It appears that an arctic fauna specifically resembling that of the present seas extended farther to the south than now. This opinion is derived partly from the known habitations of the corresponding living species, and partly from the abundance of certain genera of shells and the absence of others. The date of the refrigeration thus inferred appears to coincide very nearly with the era of the dispersion of erratic blocks over Europe and North America, a phenomenon which will be ascribed in the sequel to the cold then prevailing in the northern hemisphere. The force, moreover, of the German critic's objection, has been since in a great measure destroyed by the larger and more profound knowledge acquired in the last few years of the ancient Carbinoferes flora, which has led the ablest botanists to adopt the opinion that the climate of the cold period was remarkable for its warmth, moisture, equability, and freedom from cold rather than the intensity of its tropical heat. We are therefore no longer entitled to assume that there has been a constant and gradual decline in the absolute amount of heat formerly contained in the atmosphere and waters of the ocean, such as it was conjectured might have emanated from the incandescent central nucleus of a new and nearly fluid planet before the interior had lost, by radiation into surrounding space, a great part of its original high temperature, astronomical causes of fluctuations in climate. Sir John Herschel has lately inquired whether there are any astronomical causes which may offer a possible explanation of the difference between the actual climate of the Earth's surface and those which formally appear to have prevailed. He has entered upon this subject, he says, impressed with the magnificence of that view of geological revolutions which regards them rather as regular and necessary effects of great and general causes than as resulting from a series of convulsions and catastrophes, regulated by no laws and reducible to no fixed principles. Geometers, he adds, have demonstrated the absolute invariability of the mean distance of the Earth from the Sun, whence it would at first seem to follow that the mean annual supply of light and heat derived from that luminary would be alike invariable. But a closer consideration of the subject will show that this would not be a legitimate conclusion, but that, on the contrary, the mean amount of solar radiation is dependent on the eccentricity of the Earth's orbit and therefore liable to variation. Now the eccentricity of the orbit, he continues, is actually diminishing and has been so for ages beyond the records of history. In consequence, the ellipse is in a state of approach to a circle, and the annual average of solar heat radiated to the Earth is actually on the decrease. So far, this is in accordance with geological evidence, which indicates a general refrigeration of climate, but the question remains whether the amount of diminution which the eccentricity may have ever undergone can be supposed sufficient to account for any sensible refrigeration. The calculations necessary to determine this point, though practicable, have never yet been made and would be extremely laborious, for they must embrace all the perturbations which the most influential planets, Venus, Mars, Jupiter and Saturn, would cause in the Earth's orbit and in each other's movements round the Sun. The problem is also very complicated, inasmuch as it depends not merely on the ellipticity of the Earth's orbit, but on the assumed temperature of the celestial spaces beyond the Earth's atmosphere, a matter still open to discussion, and on which Monsieur Fourier and Sir J. Herschel have arrived at very different opinions. But if, says Herschel, we suppose an extreme case, as if the Earth's orbit should ever become as eccentric as that of the planet Juno or Pallas, a great change of climate might be conceived to result, the winter and summer temperatures being sometimes mitigated and at others exaggerated in the same latitudes. It is much to be desired that the calculations alluded to were executed, as even if they should demonstrate, as Monsieur Aragault thinks highly probable, that the mean amount of solar radiation can never be materially affected by irregularities in the Earth's motion, it would still be satisfactory to ascertain the point. Such inquiries, however, can never supersede the necessity of investigating the consequences of the varying position of continents, shifted as we know them to have been during successive epochs, from one part of the globe to the other. Another astronomical hypothesis respecting the possible cause of secular variations in climate has been proposed by a distinguished mathematician and philosopher, Monsieur Poisson. He begins by assuming, first, that the Sun and our planetary system are not stationary, but carried onward by a common movement through space. Secondly, that every point in space receives heat as well as light from innumerable stars surrounding it on all sides, so that if a right line of indefinite length be produced in any direction from such a point, it must encounter a star either visible or invisible to us. Thirdly, he then goes on to assume that the different regions of space, which in the course of millions of years are traversed by our system, must be of very unequal temperature, inasmuch as some of them must receive a greater, others a less quantity of radiant heat from the great stellary enclosure. If the Earth, he continues, or any other large body, pass from a hotter to a colder region, it would not readily lose in the second all the heat which it has imbibed in the first region, but retain a temperature increasing downwards from the surface, as in the actual condition of our planet. Now the opinion originally suggested by Sir W. Herschel that our sun and its attendant planets were all moving onward through space, in the direction of the constellation Hercules, is very generally thought by eminent astronomers to be confirmed. But even if its reality be no longer matter of doubt, conjectures as to its amount are still vague and uncertain, and great indeed must be the extent of the movement before this cause alone can work any material alteration in the terrestrial climates. Mr. Hopkins, when treating of this theory remarked, that so far as we were acquainted with the position of the stars not very remote from the sun, they seem to be so distant from each other, that there are no points in space among them, where the intensity of radiating heat would be comparable to that which the Earth arrives from the sun, except at points very near to each star. Thus in order that the Earth should derive a degree of heat from stellar radiation comparable to that now derived from the sun, she must be in close proximity to some particular star, leaving the aggregate effect of radiation from the other stars nearly the same as at present. This approximation however to a single star could not take place consistently with the preservation of the motion of the Earth about the sun according to its present laws. Suppose our sun should approach a star within the present distance of Neptune. That planet could no longer remain a member of the solar system, and the motions of the other planets would be disturbed in a degree which no one has ever contemplated as probable since the existence of the solar system. But such a star, supposing it to be no larger than the sun and to emit the same quantity of heat, would not send to the Earth much more than one thousandth part of the heat which she derives from the sun, and would therefore produce only a very small change in terrestrial temperature. There is still another astronomical suggestion respecting the possible causes of secular variations in the terrestrial climates which deserves notice. It has long been known that certain stars are liable to great and periodical fluctuations in splendor, and so J. Herschel has lately ascertained, January 1840, that a large and brilliant star called Alpha Orionis sustained in the course of six weeks a loss of nearly half its light. This phenomenon, he remarks, cannot fail to awaken attention and revive those speculations which were first put forth by my father, Sir W. Herschel, respecting the possibility of a change in the luster of our sun itself. If there really be a community of nature between the sun and fixed stars, every proof that we obtain of the extensive prevalence of such periodical changes in those remote bodies adds to the probability of finding something of the kind nearer home. Referring then to the possible bearing of such facts on ancient revolutions in terrestrial climates, he says that it is a matter of observed fact that many stars have undergone in past ages within the records of astronomical history very extensive changes in a parent luster without a change of distance adequate to producing such an effect. If our sun were even intrinsically much brighter than at present, the mean temperature of the surface of our globe would, of course, be proportionally greater. I speak not now of periodical but of secular changes. But the argument is complicated with the consideration of the possibly imperfect transparency of the celestial spaces. And with the cause of that imperfect transparency, which may be due to material non-luminous particles diffused irregularly in patches analogous to nebulae, but of greater extent to cosmical clouds in short, of whose existence we have, I think, some indication in the singular and apparently capricious phenomena of temporary stars, and perhaps in the recent extraordinary sudden increase and hardly less sudden diminution of Ita Argus. More recently, 1852, Schwabe has observed that the spots on the sun alternately increase and decrease in the course of every ten years, and Captain Sabine has pointed out that this variable obscuration coincides in time both as to its maximum and minimum with changes in all those terrestrial magnetic variations which are caused by the sun. Hence, he infers that a period of alteration in the spots is a solar magnetic period. Assuming such to be the case, the variable light of some stars may indicate a similar phenomenon, or they may be stellar magnetic periods, differing only in the degree of obscuration and its duration. And as hitherto we have perceived no fluctuation in the heat received by the earth from the sun coincident with the solar magnetic period, so the fluctuations in the brilliancy of the stars may not perhaps be attended with any perceptible alterations in their power of radiating heat. But before we can speculate with advantage in this new and interesting field of inquiry, we require more facts and observations. Supposed gradual diminution of the earth's primitive heat. The gradual diminution of the supposed primitive heat of the globe has been resorted to by many geologists as the principal cause of alterations of climate. The matter of our planet is imagined, in accordance with the conjectures of Leibniz, to have been originally in an intensely heated state, and to have been parting ever since with portions of its heat and at the same time contracting its dimensions. There are undoubtedly good grounds for inferring from recent observation and experiment that the temperature of the earth increases as we descend from the surface to that slight depth to which man can penetrate, but there are no positive proofs of a secular decrease of internal heat accompanied by contraction. On the contrary, Laplace has shown, by reference to astronomical observations made in the time of Hipparchus, that in the last two thousand years at least there has been no sensible contraction of the globe by cooling, for had this been the case even to an extremely small amount, the day would have been shortened, whereas its length has certainly not diminished during that period by one-three-hundredth of a second. Baron Fourier, after making a curious series of experiments on the cooling of incandescent bodies, considers it to be proved mathematically that the actual distribution of heat in the earth's envelope is precisely that which would have taken place if the globe had been formed in a medium of a very high temperature and had afterwards been constantly cooled. He contends that although no contraction can be demonstrated to have taken place within the historical period, the operation being slow at the time of observation limited, yet it is no less certain that heat is annually passing out by radiation from the interior of the globe into the planetary spaces. He even undertook to demonstrate that the quantity of heat thus transmitted into space in the course of every century through every square meter of the earth's surface would suffice to melt a column of ice having a square meter for its space and being three meters, or nine feet ten inches, high. It is at the same time denied that there is any assignable mode in which the heat thus lost by radiation can be again restored to the earth and consequently the interior of our planet must, from the moment of its creation, have been subject to refrigeration and is destined together with the sun and stars forever to grow colder. But I shall point out in the sequel, chapter 31, many objections to these views and to the theory of the intense heat of the earth's central nucleus until then inquire how far the observed augmentation of temperature, as we descend below the surface, may be referable to other causes unconnected with the supposed pristine fluidity of the entire globe. Principles of Geology by Charles Lyle Theory of the Progressive Development of Organic Life at Successive Geological Periods Theory of the Progressive Development of Organic Life Evidence in its support inconclusive were tabulated animals and plants of the most perfect organization in strata of very high antiquity, differences between the organic remains of successive formations, comparative modern origin of the human race, the popular doctrine of successive development not established by the admission that man is of modern origin, introduction of man to what extent a change in the system, progressive development of organic life. In the preceding chapters, I have considered whether revolutions in the general climate of the globe afford any just ground of opposition to the doctrine that the former changes of the earth which are treated of in geology belong to one uninterrupted series of physical events governed by ordinary causes. Against this doctrine, some popular arguments have been derived from the great vicissitudes of the organic creation in times past. I shall therefore proceed to the discussion of such objections which have been thus formally advanced by the late Sir Humphrey David. It is impossible, he affirms, to defend the position that the present order of things is the ancient and constant order of nature, only modified by existing laws. In those strata which are deepest and which must consequently be supposed to be the earliest deposited, forms even of vegetable life are rare. Shells and vegetable remains are found in the next order. The bonds of fishes and oviparous reptiles exist in the following class. The remains of birds with those of the same genre mentioned before in the next order. Those of quadrupeds of extinct species in a still more recent class. And it is only in the loose and slightly consolidated strata of gravel and sand and which are usually called diluvian formations that the remains of animals such as now people the globe are found with others belonging to extinct species. But in none of those formations whether called secondary, trietyary or diluvian have the remains of men or any of his works been discovered. And whoever dwells upon this subject must be convinced that the present order of things and the comparatively recent existence of men as the master of the globe is as certain as the destruction of a former and a different order and the extinction of a number of living forms which have no types in being. In the oldest secondary strata there are no remains of such animals as now belong to the surface. And in the rocks which may be regarded as more recently deposited those remains occur but rarely and with abundance of extinct species. There seems as it were a gradual approach to the present system of things and the succession of distractions and creations preparatory to the existence of men. In the above passage the author deduces two important conclusions from geological data. First that in the successive groups of strata from the oldest to the most recent there is a progressive development of organic life from the simplest to the most complicated forms. Secondly that man is of comparatively recent origin and those conclusions he regards as inconsistent with the doctrine that the present order of things is the ancient and constant order of nature only modified by existing laws. With respect then to the first of those propositions we may ask whether the theory of the progressive development of animal and vegetable life and their successive advancement from a simple to a more perfect state has any secure foundation in fact. No geologist who are in possession of all the data now established respecting fossil remains will for a moment content for the doctrine in all its detail as laid down by the distinguished philosopher to whose opinions we have referred but naturalists who are not unacquainted with recent discoveries continue to defend it in a modified form. They say that in the first period of the world by which they mean the earliest of which we have yet brought to light any memorials the vegetation was characterized by a predominance of cryptogamic plants while the animals which coexisted were almost entirely confined to zoophytes, testesia and a few fish. Plants of a less simple structure conifery and circady flourished largely in the next epoch when oviparous reptiles began also to abound. Lastly the terrestrial flora became most diversified and most perfect when the highest orders of animals the mammalia and birds were called into existence. Now in the first place it may be observed that many naturalists are guilty of no small inconsistency in endeavoring to connect the phenomena of the earliest vegetation with the nascent condition of organic life and the same time to deduce from the numerical predominance of certain forms the greater heat of uniformity of the ancient climate. The arguments in favor of the later conclusions are without any force unless we can assume that the rules followed by author of nature in the creation and distribution of organic beings were the same formally as now and that as certain families of animals and plants are now most abundant in or exclusively confined to regions where there is a certain temperature a certain degree of humidity a certain intensity of life and other conditions so also analogous phenomena were exhibited at every former era. If the postulate be denied and the prevalence of particular families be declared to depend on a certain order of precedence in the introduction of different classes into the earth and if it be maintained that the standard of organization was raised successively we must then ascribe the numerical preponderance in the earlier ages of plants or simpler structure not to the heat or other climatal conditions but to those different laws which regulate organic life in newly created worlds. Before we can infer a warm and uniform temperature in high latitudes from the presence of 250 species of ferns some of them are borescent accompanied by lycopodiasis of large size and arachnid we must be permitted to assume that at all times past present and future a heated and moist atmosphere pervading the northern hemisphere has a tendency to produce in the vegetation a predominance of analogous forms. It should moreover be borne in mind when we are considering the question of development from a botanical point of view the naturalists are by no means agreed as to the existence of ascending scale of organization in the vegetable world corresponding to that which is very generally recognized in animals from the sponge to man in the language of dubla wheel there may be a progressive chain of being although often broken and imperfect but if we seek to classify plants according to a linear arrangement ascending gradually from the lichen to the lily or the rose we encounter incomparably greater difficulties yet the doctrine of a more highly developed organization in the plants created at successive periods presupposes the admission of such a graduated scale we have as yet obtained but scant information respecting the state of terrestrial flora at periods antecedent to the call in the carboniferous epoch about 500 species of fossil plants are enumerated by adolf bronkneyard which we may safely regard as mere fragment of an ancient flora since in europe alone there are now no less than 11 000 living species i have already hinted that the plants which produce coal were not drifted from a distance but that nearly all of them grew on the spots where they became fossil they appear to have belonged as before explained page 150 to a peculiar class of stations to low level and swampy regions in the deltas of large rivers slightly elevated above the level of the sea from the study therefore of such vegetation we can derive but little insight into the nature of the contemporaneous upland flora still less of the plants of the mountainous or alpine country and if so we are unable to account for the apparent monotony of the vegetation although its uniform character was doubtless in part owing to a greater uniformity of climate than prevailing throughout the globe some of the commonest trees of this period such as the sigillaria which united the structure of ferns and of saikadi departed very widely from all known living types the conifery and ferns on the contrary were very closely allied to living genera it is remarkable that none of the exogenous of lindley dichotolidons angiosperms of bronchniart which comprise the four fifths of the living flora of the globe and include all the forest trees of europe except the third tribe have yet been discovered in the coal measures and a very small number 15 species only of monocotolidons if several of those last are true plants an opinion to which messes lindley, hunger, corda and other botanists of not incline the question whether any of the most highly organized plants are to be met with an ancient strata is at once answered in an affirmative but the determination of those palms being doubtful we have as yet in the coal no positive proofs either of the existence of the most perfect or of the most simple forms of flowering or flowerless vegetation we have no fungi, lichens, hepatici or mosses yet this later class may have been as fully represented then as now in the flora of the secondary eras all botanists agree that palms existed although in europe plants of the family of zemia and sycas together with conifery predeminated and must have given a peculiar aspect to the flora as only 200 or 300 species of plants are known in all the rocks ranging from the trios to the oolite inclusive our data are too scanty as yet to affirm whether the vegetation of this second epoch was or was not on the whole of a simpler organization than that of our own times in the lower cretaceous formation near ixley-chappelle the leaves of great many dichotolidonous trees have lately been discovered by dr debuie establishing the important fact of coexistence of a large number of angiosperms with saicady and with that rich reptilian fauna comprising the ichthyosaur, lysiosaur and pterodactyl which some had supposed to indicate a state of atmosphere unfavorable to dichotolidonous vegetation the number of plants either to obtain from tertiary strata of different ages is very limited but is rapidly increasing they're referable to a much greater variety of families and classes than an equal number of fossil species taken from secondary or primary rocks the angiosperms bearing the same proportion to the gymnosperms and acrogens as in the present flora of the globe this greater variety may doubt please be partly ascribed to the greater diversity of stations in which the plants grew as we have in this case an opportunity rarely enjoyed in studying the secondary fossils of investigating inland or lacustrine deposits accumulated at different heights above the sea and containing the memorials of plants washed down from adjoining mountains in regard then to the strata from cretaceous to the upper most tertiary inclusive we may affirm that we're finding them all the principle classes of living plants and during these vast laps of time four or five complete changes in the vegetation occurred yet no step whatever was made in advance to any of those periods by the addition of more highly organized species if we next turn to the fossils of the animal kingdom we may inquire whether when they are arranged by the geologists in a chronological series they imply that beings of more highly developed structure and greater intelligence enter upon the earth at successive epochs those of the simplest organization being the first created and those more highly organized being the last our knowledge of the silurian fauna is at present derived entirely from rocks of marine origin no fresh water strata of such high antiquity heaven yet been met with the fossils however of those ancient rocks at once reduced the theory of progressive development to within very narrow limits for already they comprise a very full representation of the radiata malaska and articulata proper to the sea thus in the great division of radiata we find a steariot and heliandsoid theophytes besides grinoid and cystidian echinoderms in the malaska between 200 and 300 species of cephalopoda are enumerated in the articulata we have the crustaceans represented by more than 200 species of trilobites besides other genera of the same class the remains of fish are as yet confined to the upper part of the silurian series but some of those belong to placoid fish which occupy a high grade in the scale of organization some naturalists have assumed that the earliest fauna was exclusively marine because we have not yet found a single silurian helix insect birth terrestrial reptile or mummifier but when we carry back our investigation to a period so remote from the present we ought not to be surprised if the only accessible strata should be limited to deposits formed far from land because the ocean probably occupied then as now the greater part of the earth's surface after so many entire geographical revolutions the chances are nearly three to one in favor of our finding that such small portions of the existing continents and islands as exposed silurian strata to view should coincide in position with the ancient ocean rather than the land we must not therefore too hastily infer from the absence of fossil bonds of mammalia in the older rocks that the highest class of vertebrated animals did not exist in remotor ages there are regions at present in the indian and pacific oceans co extensive in area with the continents of europe and north america where we might dredge the bottom and draw up thousands of shells and corals without obtaining one bone of a land quadruped suppose our mariners were to report that on sounding in the indian ocean near some coral reefs and at some distance from the land they drew up on hooks attached to their line portions of their part elephant or taper should we not be skeptical as to the accuracy of their statements and if we had no doubt of their veracity might we not suspect them to be unskillful naturalists or if the fact were unquestioned should we not be disposed to believe that some vessel had been wrecked on the spot the casualties must always be rare by which land quadrupeds are swept by rivers far out into the open sea and still rarer the contingency of such a floating body not being devoured by sharks or other predatious fish such as where those of which we find the teeth preserved in some of the carboniferous strata but if the carcass should escape and should happen to sink where sediment was in the act of accumulating and if the numerous causes of subsequent disintegration should not face all the traces of the body included for countless ages in solid rock is it not contrary to all calculation of chances that we should not hit upon the exact spot that mere point in the bed of an ancient ocean where the precious relic was entombed can we expect for a moment when we have only succeeded amidst several thousand fragments of corals and shells in finding a few bones of aquatic or amphibious animals that we should meet with a single skeleton of an inhabitant of the land clarence in his dream saw in the slimy bottom of the deep a thousand fearful wrecks a thousand men that fishes gnawed upon wedges of gold great anchors heaps of pearl had he also beheld amid the dead bones that lay scattered by the carcasses of lions deer and the other wild tenons of the forest and the plane the fiction would have been deemed unworthy of the genius of Shakespeare so daring disregard of probability and violation of analogy would have been condemned as unpardonable even where the poet was painting those in congress images which present themselves to a disturbed imagination during the visions of the night until lately it was supposed that the old red sandstone or devonian rocks contained no vertebrate remains except those of fish but in 1950 the footprints of a chelonian and in 1951 the skeleton of reptile allied both to the battrations and lizards were found in the sandstone of that age near Elgin in Scotland up to the year 1844 it was laid down as a received dogma in many works of high sovereignty in geology that reptiles were not created until after the close of the carboniferous epoch in the course of the year however hermon one mayor announced the discovery in the coal measures of range bavaria of a reptile called by him apotheon related to the salamanders and in the 1847 three species of another genus called archiosaurus by gold fuzz were obtained from the coal of sasburg between rivers and sasburg the footprints of a large quadruped probably but racian had also been observed by dr king the carboniferous rocks of pennsylvania in 1844 the first example of the bones of a reptile in the coal of north america was detected so lately as september 1852 by mr g w doson and myself in nova scoscia those remains referred by masses weyman and owen to a perinebran chiate but racian were met with in the interior of an erect fossil tree apparently a sagillaria they seem clearly to have been introduced together with the sediment into the tree during its submergence and after it had decayed and was standing as a hollow cylinder of a bark this bark being now converted into coal when agassi in his great work on fossil fish described 152 species of ichthyolites from the coal he found them to consist of 94 placoids belonging to the families of shark and ray and 58 ganoids one family of the later he called suroid fish including the megalithus and halopticus often of great size and all predatious although true fish and not intermediate between that class and reptiles they seem to have been more highly organized than any living fish reminding us of the skeletons of psorians by the close suture of the cranial bones their large conical teeth striated longitudinally and the articulation of the spinos processes with vertebra among living species they are most nearly allied to the lapidosterous or bony pike of the north american rivers before the recent progress of discovery above alluded to had shown the fallacy of such ideas it was imagined by some geologists that this ichthyotic type was the more highly developed because it took the lead at the head of nature before the class of reptiles had been created the confident assumption indulged in till the year 1844 the reptiles were first introduced into the earth in the parameon period shows the danger of taking for granted that the date of the creation of any family of animals or plants in past time coincides with the age of the oldest stratified rock in which the geologist has detected its remains nevertheless after repeated disappointments we find some naturalist as much disposed as ever to rely on such negative evidence and to feel now as sure that reptiles were not introduced into the earth still after the salurian epoch as they were in 1844 that they appeared for the first time at an era subsequent to the carboniferous scanty as is the information here that obtained in regard to the articulator of the coal formation we have at least a certain that some insects winked their way through the ancient forests in the iron stone of colbrook dale two species of colioptera of the linean genus curculio have been met with and the neuropterous insect resembling a corridolus together with another of the same order related to pasmida as an example of insectivorous arachnida i may mention a scorpion of the bohemian coal figured by count sternberg in which even the ice skin and minut hires were preserved we need not despair therefore of obtaining eventually fossil representatives of all the principal orders of hexapods and arachnida in carboniferous strata end of chapter nine part one chapter nine part two of principles of geology this is the librae walks recording all rebrew walks recordings are in the public domain for more information or to volunteer please visit librae walks dot org principles of geology by char slyle chapter nine part two next in chronological order above the coal comes the allied magnesium limestone or permen group and the second reformations from the trios to the choc inclusive those rocks comprise the monuments of a long series of ages in which reptiles of every variety of size form and structure people to the earth so that the whole period and especially that of the lies and all light has been sometimes called the age of reptiles as there are now mammalia entirely confined to the land others which like the bat and vampire fly in the air others again of amphibious habits frequenting rivers like the hippopotamus otter and beaver others exclusively aquatic and marine like the seal whale or narwhal so in the early ages under consideration there were terrestrial winged and aquatic reptiles there were iguanodons walking on the land pterodactyl swinging their way through the air monitors and crocodiles in the rivers and ichthyosaurs and plesiosaurus in the ocean it appears also that some of those ancient soreans approximated more nearly in their organization to the type of living mammalia than do any of the reptiles now existing in the vast range of strata above alluded to comprising the permian the upper new red sandstone and mueshell calc the liais ore light wielding green sand and choc scarcely any well authenticated instances of the occurrence of fossil birds in europe are on record and only two or three of fossil mammalia in regard to the absence of birds they are usually wanting for reasons afterwards to be explained c chapter 47 in the deposits of all ages even in the tertiary periods where we know that birds as well as land quadruplets abounded some at least of the fossil remains formally referred to this class in the wilderness a great freshwater deposits below the choc have been recently shown by mr owen to belong to pterodactyls but in north america still more ancient indications of existence of the fissure tribe have been detected the fossil foot marks of a great variety of species of various sizes some larger than the ostrich others smaller than the plower haven't been observed those bipods have left marks of their footsteps on strata of an age decidedly intermediate between the liais and the coal figure eight shows silo chasirium prioste valencianus amphiserium owen lovogeo from the slate of stones filled near oxford the examples of mammalia above alluded to are confined to the trios and the ore light in the former the evidence is as yet limited to two small molar teas described by professor pleaning in 1847 under the generic name of microlastice they were found near stuttgart and possess the double fangs so characteristic of mammalia the other fossil remains of the same class were derived from one of the inferior members of the aulitic series in oxfordshire and afford more and full satisfactory evidence consisting of the lower joes of three species of small quadruplets about the size of a mole kuvye when he saw one of them during the visit to oxford in 1818 referred it to the marsupial order stating however that it differed from all known carnivora in having 10 molar teas in a row professor owen afterwards pointed out that the job belonged to an extinct genus having considerable affinity to a newly discovered australian mammalia the mermicobius of waterhouse which has nine molar teeth in the lower joe figure nine figure nine shows mermicobius fasiatus waterhouse recent from swan river lower joe of the natural size a more perfect specimen enabled mr. owen in 1846 to prove that the inflection of the angular process of the lower joe was not sufficiently marked to entitle the osteologist to infer that this quadrupet was marsupial as the process is not bent inward in a greater degree than in the mole or hedgehog hence the genus anphyserium of which there are two species from stonesfield must be referred to the ordinary or placental type of insectivorous mammals although it approximates in some points of structure of the mermicobius and a light marsupials of australia the other contemporary genus called fascholocerium agrees much more nearly in astrological character and precisely in the number of the teeth with the opossums and is believed to have been truly marsupial figure 10 figure 10 signed natural size shows fascholocerium booklandi owen seen d delphi booklandi brought lower joe from stonesfield first the joe magnified twice in lengths second the second molar tooth magnified six times the occurrence of those most ancient memorials of the mammiforus type in so low a member of the owelitic series while no other representatives of the same class if we accept the microlastice have yet been found in any other of the inferior or superior secondary strata is a striking fact and should serve as a warning to us against hasty generalizations founded solely on negative evidence so important an exception to a general rule may be perfectly consistent with the conclusion that a small number of only mml inhabited european latitudes when our secondary rocks were formed but it seems fatal to the theory of progressive development or to the notion that the order of precedence in the creation of animals considered chronologically has precisely coincided with the order in which they would be ranked according to perfection or complexity of structure it was for many years suggested that the marsupial order to which the fossil animals of stonesfield were supposed exclusively to belong constitutes the lowest grade in the class mammalia and that this order of which the brain is of more simple form wins an inferior degree of intelligence if therefore in the owelitic period the marsupial tribes were the only warm blooded quadrupeds which had as yet appeared upon our planet the fact it was said confirmed the theory which teaches that the creation of the more simple forms in each division of the animal kingdom preceded that of the more complex but on how slender a support even if the facts had continued to hold true did such important conclusions hang and australian continent so far as it has been hazard to explode contains no indigenous quadrupeds save those of the marsupial order with the exception of a few small rodents while some neighboring islands to the north and even southern africa in the same latitude as australia abound in mammalia of every tribe except the marsupial we are entirely unable to explain on what physiological or other laws this singular diversity in the habitations of living mammalia depends but nothing is more clear than that the causes which stem so peculiar a character on two different provinces of wide extent are wholly independent of time or the age or maturity of the planet the strata of the wilderness although of a later date than the owelite or stones filled and also filled with the remains of large reptiles both terrestrial and aquatic have not yielded as yet a single marsupial bone where we to assume on such scanty data that no warm blooded quadrupeds were then to be found throughout the northern hemisphere there would still remain a curious subject of speculation whether the entire suppression of one important class of vertebra such as the mammiferous and the great development of another such as reptilian implies a departure from fixed and uniform rules governing the fluctuation of the animal world such rules for example as appear for one century to another to determine the growth of certain tribes of plants and animals in arctic and of other tribes in tropical regions in australia new zealand and many other parts of the southern hemisphere where the indigenous land quadrupeds are comparatively few and of small dimensions the reptiles do not predominate in number or size the deposits formed at the mouth of an australian river within the tropics might contain the bones of only a few small marsupial animals which like those of stonesfield might thereafter be discovered with difficulty by geologists but there would at the same time be no megalosauri and other fossil remains showing that large surians were plentiful on the land and in the waters at a time when mammalia were scarce this example therefore would afford a very imperfect parallel to the state of the animal kingdom supposed to have prevailed during the secondary periods when a high temperature pervaded european latitudes it may nevertheless be advantageous to point to some existing anomalies in the geographical development of distinct classes of vertebra which may be comparable to form conditions of the animal creation brought to light by geology thus in the arctic regions at present reptiles are small and sometimes wholly wanting where birds large land quadrupeds and cetacea abound we meet with birds wolves foxes mask oxen and deer walruses seals whales and narwhals in regions of ice and snow where the smallest snakes afts and frogs are rarely if ever seen a still more anomalous state of things presents itself in the southern hemisphere even in the tempered zone between the latitudes 52 and 56 degrees south as for example in tiara del fiego as well as in the woody regions immediately north of the straits of magellan and in the falkland islands no reptiles of any kind are met with not even a snake lizard or frog but in those same countries we find the guanaco a kind of llama a deer the puma a large species of fox many small rodentia besides the seal and otter together with spore poise whale and other cetacea on what grand laws in the animal physiology those remarkable phenomena depend cannot in the present state of science be conjectured not could we predict whether any opposite condition of the atmosphere in respect to heat moisture and other circumstances would bring about a state of animal life which might be called the converse of the above described namely a state in which reptiles of every size and order might abound and mammalia disappear the nearest approximation to such a fauna is found in the galapagos archipelago those islands situated under the equator and nearly 600 miles west of the coast of peru have been called the land of reptiles so great is the number of snakes large tortoises and lizards which they support among the lizards the first living species proper to the ocean has been discovered yet although some of those islands are from three to four thousand feet high and one of them 75 miles long they contain with the exception of small mouse no indigenous mammoth even here however it is true that in the neighboring sea there are seals and several kinds of cetacea it may be unreasonable to look for a near analogy between the fauna now existing in any part of the globe and that which we can show to have prevailed when our secondary strata were deposited because we must always recollect that a climate like that now experienced at the equator coexisting with the unequal days and nights of European latitudes was a state of things to which there is now no counterpart on the globe consequently the type of animal and vegetable existence required for such a climate might be expected to deviate almost as widely from that now established as do the flora and fauna of our tropical differ from those of our arctic regions in the tertiary strata the tertiary formations were deposited when the physical geography of the northern hemisphere had been entirely altered large inland lakes had become numerous as in central France and other countries there were gulfs of the sea into which considerable rivers emptied themselves and where strata like those of the Paris basin were accumulated there were also formations in progress in shallow seas not far from shore such as are indicated by portions of the phalons on the lawyer and the English crack the proximity the four of large tracts of dry land to the sea and lakes then existing may in great measure explain why the remains of land animals so rare in the older strata are not uncommon in those more modern deposits yet even those have sometimes proved entirely destitute of mammiferous relics for years after they had become celebrated for the abundance of their fossil estacia fish and reptiles thus the calcare glossier and marine limestone of the district drowned paris had afforded to collectors more than eleven hundred species of shells besides many though fights iconodermata and the teeth of fish before the bones of one or two land quadruplets were met with in the same rock the strata called London and plastic clay in England have been studied for more than half a century and about 400 species of shells 50 or more of fish besides several kinds of chelonian and sorean reptiles were known before a single mammifer was detected at length in the year 1839 there were found in this formation the remains of a monkey and a possum a bat and a species of the instinct genus hierococereum lie to the peccary or hawk tribe if we examine the strata above the London clay in England we first meet with mammiferous remains in the Isle of Wight in bats also belonging to the Iocene epoch such as remains of the paleocereum anoplasyrum and other extinct quadruplets agreeing very closely with those first found by Kovye near paris in strata of the same age and of similar freshwater origin in France we meet with another fauna both concological and mammalian in the myocene fallons of the lawyer above which in the sand and series in great britain we arrive in the coraline crack of saffolk a marine formation which has yielded three or four hundred species of shells very different from the eocene to stasia and of which a large proportion although a minority of the whole number are recent besides many corals acony for a minifera and fish but as yet no relic decidedly mammalian except the ear bone or whale in the shelly sand provincially term red crack in saffolk which immediately succeeds the coraline constituting a newer number of the same tertiary group about 250 species of shells have been recognized of which a still larger proportion are recent they are associated with numerous teeth of fish but no sign of a warm blooded quadruplet had been detected until 1839 when the teeth of leopard a bear a hawk and the species of ruminant were found at newburn in saffolk and since that time several other genera of mammalia have been met with in the same formation or in the red crack of a still newer date is the norwich crack a fluvia marine deposit of the paleocene epoch containing a mixture of marine fluvia tile and land shells of which 90 percent or more are recent those bats since the time of their first investigation have yielded a supply of mammalian bones of the genera mastodon elephant rhinoceros pig horse deer ox and others the bodies of which may have been washed down into the sea by rivers draining land of which contiguity is indicated by the occasional presence of terrestrial and freshwater shells our acquaintance with the new pleocene mammalia in europe south america and australia is derived chiefly from cavern deposits a fact which we ought never to forget if we desire to appreciate the superior facilities we enjoy for studying the more modern and compared to the more ancient terrestrial faunas we know nothing of the fossil bones which must have been enclosed in the stalagmite or caverns in the older pleocene or in the myocene or eocene epochs much less can we derive any information respecting the inhabitants of the land from a similar source when we carry back our inquiries to the wilden or carboniferous epochs we are as well assured that land and rivers then existed as that they exist now but it is evident that even a slight geographical revolution accompanied by the submergence and denudation of land would reduce to an extreme improbability the chance of our hitting on those minute points of space where caves may once have occurred in limestone rocks fossil quadrumina until within a few years 1836 8037 not a single bone of any quadruminous animal such as the oran ape baboon and monkey had been discovered in a fossil state although so much progress had been made in bringing to light the extinct mammalia of successive tertiary eras both carnivorous and herbivorous the total absence of those antrophomorphous stripes among the records of a former world had led some to believe that the type of organization most newly resembling the human came so late in the order of creation as to be scarcely if at all interior to that of man that such generalization was premature i endeavored to point out in the first edition of this work in which i stated that the bones of quadruplets he said to mad with in the tertiary deposits were chiefly those which frequent marshes rivers or the borders of lakes as the elephant rhinoceros hippopotamus taper hawk deer and ox while species which live in trees are extremely rare in a fossil state i also hinted that we had as yet no data for determining how great a number of one kind we ought to find before we have a right to expect a single individual of the other lastly i observed that the climate of the more modern or post-eocene tertiary periods in england was not tropical and that in regard to the london clay of which the crocodiles turtles and fossil fruits implied a climate hot enough for the quadrumana we had as yet made too little progress in ascertaining what were the eocene pachydermata of england to entitle us to expect to have discovered any quadrumana of the same date since those remarks were first written in 1829 a great number of extinct species have been added to our collection of tertiary mammalia from great britain and other parts of the world at lengths between the years 1836 and 1839 a few remains of quadrumana were found in france and england india and brazil those of india belonging to more than one extinct species of monkey were first discovered near a satellite in latitude 30 degree north in tertiary strata of which the age is not yet determined the brazilian fossil brought from the basin of the river thus well has about latitude 18 degree south is referable to a form now peculiar in america allied to the genus calisthrix the species being extinct the skull and other bones met with in the south of france belong to gibbon or one of the tailless apes which stand next in the scale of organization to the orn it occurred at san san about 50 miles west of the loose in latitude 43 degrees 40 minutes north in freshwater strata probably of the myosin or middle tertiary period lastly the england quadrumana first met with occurred in a more ancient stratum than the rest and at point more remote from equator it belongs to the genus macacos is an extinct species and was found in saffolk at latitude 52 degrees in the london clay the fossil of which such as crocodiles turtles shells of the genus nautilus and many curious fruits had already learned geologists to the conclusion that the climate of that era the iosin was warm and newly tropical some years later in 1846 the joe of another british species of fossil monkey macacos leosinus was announced by mr owen as having been met with in the new europe leosin strata on the banks of temps at grace in asex accompanying the remains of hippopotamus elephant and other quadrupeds and associated with fresh water and land shells most of which are now inhabitants of the british isles when we consider the small area of the earth's surface here to explore geologically and the new discoveries brought to light daily even in the environs of great european capitals we must feel that it would be rushed to assume that the lower iosin deposits mark the era of the first creation of quadrumena it would however be still more unphilosophical to infer as some writers have done from a single extinct species of this family obtained in latitude far from the tropics that the iosin quadrumena did not attain as high a grade of organization as they do in our own times what would the naturalist know of the apes and ornx now contemporary with men if our investigations were restricted to such northern latitudes as those where alone the geologist has hitherto found all the first quadrumena of europe end of the chapter nine part two