Chapter VI: Part 6

The conversion of the igneous liquid surface into solid matter, could only have taken place in successive shells or concentric layers; hence would arise a stratified character. And as the cooling proceeded, lowering the mean temperature of the whole mass, a consequent diminution of bulk must have taken place, according to the well known law of expansion by heat and contraction on cooling. Such diminution in bulk must have broken the strata into fragments, through the fissures of which, according to the laws of hydrostatics, the fluid mass beneath would rise until the equilibrium of rotation would have been obtained, and the strata, originally concentric, would be dislocated and turned in every possible direction, pierced with veins and dikes of all possible magnitude, from slender threads to mountain masses, caused by the cooling and consolidation of the rising fluid, and occasionally spreading in overlying currents, congealed and fixed in ridges and chains. These veins and dykes would present different characters, according to the dates of their elevation. If raised at a period when the surface was still of high temperature, they must have crystallized slowly, and in a perfect manner; at diminished temperatures, the crystallization would be less complete; if raised into the mass of ocean, they would assume one character; if coming in contact with air, another. A breaking of the bed of the ocean, and bringing its waters in contact with the liquid mass beneath, might produce consequences extending in their action to districts of the globe, the most remote from those in which the convulsion occurred; for the water, rising into vapour, would tend to extend itself in one uniform atmosphere over the whole surface of the globe, and might be precipitated in unusual abundance wherever causes of condensation existed. Thus, partial, or even total deluges, may have occurred, great portions of the ocean being hurried in vapour from its bed, and precipitated upon the land whose temperature is not affected by the distant catastrophe.

The waters might, in some cases, flow directly back to the ocean, in others might accumulate in basins and form lakes, fresh at first, and gradually becoming saline. These in turn might burst their bounds, carrying ruin and devastation in their course, or might by evaporation be dried up, and be again filled by a recurrence of the original cause of supply.

Such violent and rapid action would finally be exhausted by the gradual cooling of the earth, but the outer crust would still press on the igneous fluid beneath, and although far less liable to rupture, its fluid action might yet enable it to force its way occasionally to the surface, but at distant intervals, and with diminished energy. Now, a new series of phenomena must occur, similar to the more familiar of those we see acting at present; at first more intense, but finally, when the state of equilibrium of temperature is reached, exactly such as we now find them both in kind and in energy.

To see how far such a view of what might have occurred, under the action of well known causes, in case of a certain original order of things, is correct, let us examine the appearances our globe actually presents.

To a systematized and general examination, it presents the appearance of a great ocean, covering about three-fourths of its whole surface, and surrounding two great, and a number almost infinite of smaller islands. The two great islands are the old and the new continents; the largest of those that remain is New-Holland. To exhibit this great ocean in its most general aspect, take an artificial globe, raise the south pole 50 deg. above the horizon, and bring New-Zealand to the meridian. The hemisphere above the horizon will now be wholly of water, with the exception of the southern part of South America on the one side, and New-Holland, with the Indian archipelago, on the other. These bear, when united, but a small proportion to the entire hemisphere. The opposite hemisphere contains more land than water; and when it is in its turn placed above the horizon, the Atlantic will be seen lying almost wholly on the western side of the meridian, and forming, with the Arctic ocean, a species of channel, narrowing from the latitude of the Cape of Good Hope towards the northern pole, and communicating with the great ocean which lies principally in the opposite hemisphere by Behring's straits. On this hemisphere are also seen parts of the Pacific and Indian oceans, which are considerably more than equal in surface to the lands which project into the opposite one.

If we turn our attention to the land, we find it unequal in its surface; and although compared with the whole diameter of the earth, the inequalities be very small, yet, compared with our own stature, they often present an imposing magnitude. These greater elevations are mountains; and we find them sometimes united in chains, sometimes isolated, and at other times uniting to form elevated plains or table lands. These table lands sometimes slope outwards, at others they are surrounded by eminences that prevent the efflux of the waters, or only admit them to pass through apertures made by their own action. Upon our continent, table lands of the latter description are to be found of great magnitude, entering as parts of the great system of the Cordilleras or Andes; in Europe they are rare, but in Tartary, Persia, and in central Africa, they occur, forming regions of great extent. In general, the greater part of the mountains of a continent appear to have a connexion more or less obvious; it has even been conceived that they form the skeleton upon which the rest of the land has been deposited, and which has determined the form of the continent. Thus we speak habitually of chains of mountains. Mountains, however, do not always present a continuous ridge, from which the peaks or more elevated summits rise, but occasionally, the groups we call chains, are composed of separate mountains divided by valleys; such are the mountains of Scotland, of Sweden, and Norway; and such is the general structure of the chain of mountains called in the state of New-York the Highlands, of whose connexion and grouping we shall hereafter speak.

This being understood, namely, that by a chain or ridge of mountains we do not necessarily intend a continuous elevation, the term may be conveniently used in order to express the configuration of mountains. These chains surround or border upon greater or less basins, which are each distinguished by the name of the principal stream that conveys its surface waters to the ocean, or they may, as has been stated, envelop a table land, whence there is no issue for the waters, or no more than a mere passage sufficient to afford them an outlet. Even if a map contain no expression of the position of mountains, we can, by mere inspection of the courses of rivers, determine the lines in which the chains are directed, and, from the size of the rivers, judge in some measure of the elevation of the district. Thus, on inspection of the map of Europe, we find four of its greatest rivers rising at no great distance from each other, the Rhine, the Rhone, the Danube, and the Po; here, then, we might infer a great elevation, and here we accordingly find its highest mountains, the Alps. In another part of this continent, we see the Dwina, the Nieper, and the Volga, diverge from points not far distant from each other, and here accordingly we find an elevated table land, two hundred miles in length by fifty in breadth, marked however by no mountain summits. In central Asia, we see a vast space inclosed by lines joining the sources of a number of mighty rivers, the Indus, the Ganges, the Barrampooter, the Irrawaddy, the Houng Ha, and Kiang Ku, the Amour, the Lena, the Yermisir, and the Oby; accordingly, here we find the greatest table land surrounded by the highest mountains of the globe. Still, however, the instance we have cited of the rivers of Russia shows, that the land whence great rivers take their rise, is not necessarily mountainous; in this case the ascent is almost imperceptible, and the summit offers the aspect of a level and marshy plain. Such also occurs in the famous boundary between the United States and Canada, where the highlands that figured in two successive treaties have disappeared, and in their supposed place has been found a series of swamps.

Attempts have been made to arrange the chains of mountains into connected systems. Of these the most successful is that of Malte-Brun.

"If we draw a line from the centre of Thibet, across Chinese
Mongolia towards Ochotsk, and thence towards Cape Tchutscki,
the eastern promontory of Asia, this line will in general
coincide with a great chain of mountains which runs from the
south-west to the north-east, and which every where descends
rapidly towards the Indian and Pacific oceans, while on the
contrary, it extends itself towards the Frozen ocean in high
plains and secondary hills. It is probable that we may some day
refer to the same rule the chain of Lapata, called the backbone
of the world, in Africa; at any rate this chain runs from the
Cape of Good Hope to that of Gardafui, in a direction
south-east and north-west, and therefore in nearly the same
direction as the great chain of Asia, but we are ignorant of
the disposition of the slopes of these mountains. We may regard
the mountains of the Happy Arabia, which are both steep and
lofty, as the link that connects the mountains of Lapata with
the table lands and mountains of Persia, which proceed from the
mountains of Thibet.

"If we follow the western coasts of America, from Behring's
straits, which hardly form a sensible interruption, to Cape
Horn, we find an uninterrupted chain of mountains. From time to
time this chain retires a little into the interior, but more
frequently it immediately borders upon the great ocean, in
immense cliffs, and often by frightful precipices. On the other
side of it, the manner in which the lakes discharge themselves,
and the direction of the great rivers, show sufficiently, that
the surface of America inclines gently towards the Atlantic
ocean.

"It results from a combination of these observations, that the
greatest chains of mountains on our globe, are ranged in an arc
of a circle around the great ocean, and the sea of India; that
they seem to present rapid descents towards the immense basin
they surround, and gentle slopes on their opposite sides; in
fine, from the Cape of Good Hope to Behring's straits, and
thence to Cape Horn, the eye of the most timid observer cannot
fail to see some trace of an arrangement, as surprising from
its uniformity, as from the vast extent of ground which it
embraces.

"Let us pause for an instant to consider this great fact of
physical geography. If we conceive ourselves placed in New
South Wales, with our face turned towards the north, we have
America on our right hand, Africa and Asia on our left. These
continents, which we hardly before ventured to approach in our
imagination, considered in this point of view, form a
consistent system, whose structure, as far as we are acquainted
with it, presents in its great features an astonishing
symmetry. A chain of enormous mountains surrounds an enormous
basin; this basin, divided into two by a vast collection of
islands, often bathes with its waves the feet of this great
primary chain of the earth."

In this chain lie the greatest mountains of the globe. One peak of the Himmalayah rises nearly five miles above the level of the sea; another has a height of 25,500 feet; and a third of 22,217 feet. In South America are Soratu, in height 25,250 feet.

Illimani, 24,000
Chimborazo, 21,400

not to mention Antisana, Mauflos, Chillau, Cotopaxi, all of which exceed in height any mountains that do not lie in this great system. Nay, did not the great Volcano of Owyhee enter into the order with a height of 18,000 feet, the list of those surpassing the other mountains of the globe, might be very much extended.

We shall have occasion hereafter to speak of the volcanic energies still exerted in this vast stony girdle, and shall therefore confine ourselves strictly to mere external form.

The arms and branches of mountain chains enclose as has been seen, basins marked by rivers which convey their surface waters to the ocean. The rains which fall on the sides of mountains and hills, unite in torrents and streams, which follow the lines of most rapid slope in their course to the sea.

The greater rivers mark the lowest part of a principal basin, on each side of which, at a greater or less distance, are to be found rising grounds, themselves hollowed out into lateral secondary basins, containing courses of water less considerable than the first, into which they cast themselves, and whose branches they are. The borders of these secondary basins are again hollowed out into basins of a third order, whose slopes also contain water courses less considerable than the preceding, into which they in turn discharge themselves. This ramification continues until we reach the smallest ravines of the boundary mountains, and the map appears, as it were, covered with a net work of rivers and lesser streams. The great valley of the Mississippi and Missouri, forms perhaps the most striking instance of this sort, upon the surface of our globe.

Rivers and streams are constantly exerting a mechanical action on the surfaces over which they run; abrading and tearing off fragments even of the hardest rocks, they roll them in their course until the velocity becomes insufficient to transport them farther. At diminished velocities they move fragments of less size, down to the smallest pebbles; at still less velocities, they transport sand, and finally earthy matter, in the most minute division. These are deposited in succession in positions corresponding to the rapidity of the stream, and hence the beds of rivers present at each of their different sections, materials of magnitude and quality corresponding to the rate at which the stream usually flows. The increase in the magnitude of streams, due to violent rains and the melting of the snows, changes the position of the substances that compose their bed, and the more easily suspended materials are often held until the stream actually meets the ocean. In such sudden increases, the streams often overflow their usual banks, and make their deposits laterally, until the constant succession of such deposits raises the adjacent ground high enough to set bounds to the further spreading of the stream. This deposit is remarkable for its taking place in greatest quantity close to the usual bed of the stream; and thus it speedily opposes natural dykes to its own redundant waters. This action is most conspicuous at points where marked changes take place either permanently or periodically in the rapidity of running water: when streams descend from mountains into lines of less descent, a deposit uniformly takes place, forming _flats_ or _intervals_, as they are styled in the United States, of which we have such beautiful instances in the valleys of the Connecticut and Mohawk, and that part of the Hudson near Albany; again, where rivers meet the sea, they are interrupted in their course by the rise of the tides of the ocean, and here again deposits take place, sometimes forming shoals and banks in the ocean itself; at other times, bars and obstructions at their own mouths; and again, deltas of solid land, constantly encroaching upon the sea. This action, which is continually going forward, is called alluvial. The delta of greatest fame, and from which the others have derived their generic name, is that of the Nile; this we have evidence, almost historic, to prove to be wholly the gift of the river. And if it no longer increase as rapidly as in former ages, the cause is obvious, for the alluvion has been pushed so far forward as to meet a strong current that sweeps along the African coast, and must carry off much of the earth the Nile discharges into the Mediterranean. The great rivers of Asia and of America carry still greater quantities of solid matter, but we have not the same distant traditions to refer to for the amount of the increase they have caused; still, however, we know that the mouth of the Mississippi has been advanced into the Gulf of Mexico several leagues since the settlement of Louisiana; and that islands of great extent are frequently formed, in the course of a single year, by the deposits of the Ganges.

We however find traces of aqueous action far more extensive and powerful than those which are now taking place under our eyes by fluviatile action. There is no part of the globe that has been examined, which does not show that it has been subjected to the action of water, in floods far more powerful than any we now are in the habit of seeing. Every where, except in the case of rocky cliffs, and steep mountains, or where we see obvious evidence of a recent elevation, we find the surface strewn with the deposits of water: boulders of greater or less size, beds of gravel, sand, and clay, form the present outer coating of the greatest part of the land. These deposits were long confounded with the alluvial, but have at length been proved, by incontrovertible evidence, to be the results of an action, which if not contemporaneous, must have been universal. We have seen an able attempt to show that this species of deposit did not take place at one and the same period, but was merely the general consequence of similar causes acting at different epochs. Our impression, we must however confess to be, that the action was not only co-extensive with the globe, but contemporaneous. It at any rate exhibits proofs the most satisfactory, that the last great and extensive change which our earth has undergone, was effected by the agency of water, in a state of rapid and violent motion. Ascribing this deposit to a single flood, it has been styled diluvial.

There are cases where alluvial deposits rest upon the diluvium, and from the depth of these it has been attempted to calculate the time that has elapsed since the former of these actions was resumed. The diluvium has also been found in caverns lying upon an ancient stalagmite, and covered again with a new formation of that modification of carbonate of lime. The thickness of the latter deposit has also been made the basis of a calculation, and although neither of these methods is to be considered as approaching to an accuracy more perfect than some hundreds of years, the two methods confirm each other in the general result, which is, that, at a date not more remote than fifty or sixty centuries, there must have taken place a total submersion of all the land, except, perhaps, the tops of high mountains, did they then exist. We have in the sacred volume, a record of such a catastrophe, the flood of Noah, and from that time to the present, no convulsion, equally extensive in its influence, has devastated the globe. Have not then the geologists who have seen in these indications the convincing evidence of that occurrence, been warranted in their inference, of the identity of an event pointed out by undeniable physical evidence, with one recorded in a history to which one of the most confirmed sceptics has recently admitted the merit of truth?

The diluvial deposits are found not only in the lower grounds, but on the tops and sides of lofty mountains; we have ourselves noted them distinctly characterized at high elevations upon the Kaatskills; they are found among the Alps at Valorsine, 6000 feet above the level of the sea, and in another place at more than 7000 feet. The excavations made in the extension of the city of New-York at Corlaer's Hook, have laid open a vast mass of diluvium, and afforded means for studying it with great facility. It in fact presented the appearance of a great cabinet of specimens of primitive and transition rocks, and it was possible in many cases to determine the very mountain whence the fragments had been torn. The most remarkable boulder, for instance, of a weight of at least an hundred tons, was distinctly recognisable as identical in every respect with the granitic syenite of Schooley's mountain, distant at least forty miles. Others had no known type nearer than Connecticut, in the opposite direction, while the gneiss and mica slate of the island of New-York, with their various embedded minerals, the serpentine and many of the magnesian minerals of Hoboken, with sandstone and trap of the Pallisadoc range, were distinctly recognisable. In this great excavation, where a region of a mile square was wholly removed, to a depth, in many places, of thirty feet, no animal remains, as far as can be learnt, were detected; thus marking a most important difference between these deposits and those of the Old continent. Such is the remark of an intelligent geologist, whom we are proud to reckon as our _collaborateur_, and to whom that branch of Natural History is under no small obligations.

"Fragments of granite and other primitive rocks, cast here and
there upon stratified formations, and interpersed in
diluvium,[10] present a fact as certain as it is astonishing.
All the chains of Mount Jura, all the mountains that precede
the Alps, the hills and plains of Germany and Italy, are strewn
with blocks of granite, often of a great dimension, and always
of a composition as pure, and as perfect a crystallization, as
the granites of the higher Alps. The same phenomenon is
repeated in the plains of Russia, of Poland, of Prussia, of
Denmark, and of Sweden. From Holstein to Eastern Prussia,
diluvial[11]grounds, sand and clay, are covered with an immense
number of blocks of granite. Near the island of Usedom, several
points of granite rock rise from the bottom of the Baltic. We
see in like manner, Scania and Jutland so filled with these
fragments, that they construct of them enclosures, houses and
churches. In the Lymfiord, a gulf of Jutland, and at some
places on the western side of that peninsula, great points of
granite rise from the bottom of the waters. But what is still
more remarkable, is to see immense masses of granite lying on
the tops of Roeduburg and Osmond, which are more than 6000
feet in height, and are therefore among the highest mountains
in the North of Europe."

Beneath the diluvial deposit, we find beds and strata of substances of different character, and which appear on a cursory view to be involved in inextricable confusion. Long and careful examination has at length been efficient in ascertaining that in this apparent disorder are to be seen the traces of an order, as perfect as that of any other mechanism of nature, and of a succession of changes by which the earth has been finally fitted for the habitation of man. These strata have been finally arranged into five distinct classes, differing in their characters and position. These have been so fully described in a former article in this Journal, by the distinguished associate whom we have already quoted, that no more remains for us to say, than what is merely necessary to keep up the connexion of our subject.

These stratified rocks or formations are remarkable for the regular order in which they succeed and overlie each other, furnishing distinct and indisputable evidence of their having been formed in succession. The first set of strata, which are never covered by any of the others, and hence are conceived to be of most recent formation, lie inclined at a small angle to the horizon. In many cases they do not assume the character of rocks, but although distinctly stratified, are often soft and friable, presenting beds of marle and clay, and thick deposits of sand. In some cases their appearance is so similar to diluvial or even alluvial deposits, that they might be mistaken for them, were it not for their more regular stratification. These are the tertiary formations of the German school, the superior order of Coneybeare and Philips.

Issuing from beneath these, and forming in their turn a considerable portion of the surface of the earth, rising occasionally into considerable hills, are strata of less uniform and regular inclination, forming basins and cavities in which the tertiary deposits are often found to lie, curved to conform to the bottoms of these basins.

The third and fourth series issue in their turn from beneath the preceding, as does the fifth from beneath the fourth. Each is marked in succession, by a greater degree of confusion or distortion in the stratification, until the last, which is apparently upheaved and thrown about without any regularity, its strata being occasionally found in positions almost vertical. Not only is the succession of the five different orders of rocks constant, but so is that in which the several rocks of each series overlie each other. This regularity of succession is, however, subject to this law; namely, that rocks of particular orders, or even the whole order itself, may be wanting in particular districts; thus, tertiary formations may be directly upon the lower order, and the second, third, and fourth, may not be present; or any one of the higher orders may lie directly upon any one of those we have stated to be inferior to it; but it has never been observed that the arrangement itself has been inverted, or that a rock which is in one place inferior, becomes, in its turn, superior in another.

The fifth, or inferior order, is uniformly found beneath one or all of the others; and, we may infer, that it in fact underlies the whole surface of the globe, forming not only the foundation of the solid land, but the original bottom on which the present bed of the sea is deposited. The rocks that compose this series are all highly crystalline in their character, are mostly composed of substances wholly or nearly insoluble in water, are wholly devoid of organic remains, and are in fact such substances as might be supposed to have been formed by slow cooling, from a state of igneous fusion. Is it then assuming too much to infer, that they are in fact the crust which has been first formed upon the surface of the earth, intensely heated by its own condensation, under the action of the gravitating force, that, communicated to it by the hand of the Creator, determined its figure, and still maintains its equilibrium. We do not include in this class, as is usually done, the crystalline rocks not stratified, as we conceive them to have been formed in another manner, to which we shall hereafter refer. All the four higher series of strata show, in the most evident manner, that their formation has been due to the action of water; the grauwacke is, perhaps, the only rock that exists among them, in which the question could, even on simple inspection of specimens, appear doubtful; but this rock lies at the base of the old red sandstone, and upon the limestone of the submedial order, or transition, as it is styled by the Wernerians, and is equally regular in its stratification with either; we cannot, therefore, admit any other cause of its formation than what is common to them.

Some of these strata are obviously mechanical, others chemical deposits; thus, the sandstones and conglomerates are certainly the products of the disintegration of older rocks by a violent abrasion of running water, and have settled when the currents have ceased to flow; all calcareous rocks, except the limestones of the inferior or fifth order, the primitive of Werner, on the other hand, appear to have been products of chemical precipitation; while there are a few cases, as in the beds of rock salt, where the deposit must have been due to evaporation.

Of all these rocks and formations, the primitive, as has already been stated, and the sandstones, are wholly devoid of organic remains. And even the last rule is to be received as not wholly free from exception; for vegetable impressions have been found, as we are credibly informed, in sandstone, at Nyack on the Hudson, and near Belleville in New-Jersey, besides some other similar cases we shall hereafter note. All the other strata present a greater or less abundance of the traces of the organic kingdoms, from the slate, which lies lowest of the fourth order, to the most recent beds of the tertiary, and to so much of the diluvium as has been examined in the old continent. And although in the isolated case of the diluvium at New-York, no fossil remains have been found, we are yet unprepared to admit this as more than an exception, and are inclined to think that the remains of the mastodon, for instance, must be diluvian, or pre-diluvian. In this opinion, however, we know that we are opposed by high authority, and therefore do not express it without hesitation.

"Organized fossil remains belong to three different classes:
the remains that have preserved their natural state, at least
in part; petrifactions; and impressions.

"The remains of the first class are principally bones, and even
entire skeletons, which, after having been stripped of the skin
and flesh that covered them, have remained, some buried in the
earth, others hidden in deep caverns. They are, sometimes,
calcined in whole or in part, without having lost their
configuration; they at others preserve, not only their texture,
but even some traces of their hair and skin. They are also
occasionally seen covered with a calcareous crust.

"Petrifactions, to use this word in its familiar sense, include
all stony bodies that have the figure of an organized body.
There are cases in which a strong solution has penetrated into
a cavity formed by an organic body that has disappeared. Then
the strong substance has occupied the cavity that has been left
empty, and has taken the external form of the body that
formerly existed there. If this body were, for instance, a
branch or trunk of a tree, the stone will have at its surface
its knots and asperities; but within, it will present all the
characters of a true stone; it will be no more, to use the
language of Hauy, than the statue of the substance that it has
replaced.

"At other times, a vegetable or animal substance, while
undergoing decomposition in a successive manner, and by obvious
degrees, is pressed by the petrifying liquid that already
surrounds it. As soon as an organic particle has disappeared,
its place is occupied by one of stone."

* * * * *

"Metallized bodies, and those which have been changed into
bitumen or carbon, belong to this system of formation; thus,
the turquoises, for instance, are the teeth of a great marine
animal; a metallic substance has penetrated them, and has
gradually replaced the softer parts of the bones.

"Impressions are often found between the plates of slaty rocks;
they are relievos or intaglios representing the skeletons of
animals, particularly fish, leaves, seeds, and entire plants,
of which the most common kind belong to the forus."

The impressions of vegetables are most abundant in the shales that accompany coal formations; those of leaves and branches are the most common, but there are a few instances in which they retain the delicate structure of the flowers. All analogy leads to the inference, that those now found in temperate climates, are of such a character as could only exist in tropical regions; and when, as in some of the newer formations, the species are identical with those which now exist, the living type is only found within the torrid zone. A still more curious fact, is their identity in similar formations in different parts of the world. At the present day, the same soil in Pennsylvania and England produces plants of very different characters, and those which are native to each are of wholly distinct genera and species, while the fossils that accompany the coal in the two countries are precisely similar. But even those brought by Parry from the polar region of Melville island, are identical with those of England, and of course with those of this distant part of the same hemisphere in which the former are formed, although the character of the climate is so diverse. At the epoch of the coal formation, there existed plants, of genera, which, in temperate climates, at present rarely rise to more than a few inches in height, and which were at that remote period of enormous size. Thus, the forus must have attained the height of from fifty to sixty feet. At present, the forus assume the size of a tree only in the very warmest climates, and even there, are far inferior in magnitude to those of the coal formation. Now, it is well known, that the large size of the living species is due to great and constant heat, and copious moisture. Hence we may fairly infer that similar circumstances existed even at Melville island, where, at the present time, for the greater part of the year, the thermometer is below the freezing point.

As further instances of the same kind, we may quote the following facts. Faujas St. Fond found, in a marly slate, covered by lava, in France, the tree cotton, the liquid amber styrax, the cassia fistula, and other plants of tropical regions. The same observer found the fruit of the arcea palm near Cologne. The elastic bitumen of Derbyshire in England, is identical with the caoutchouc, which now grows only in the warmer parts of South America; and the amber of Prussia appears to be a fossil gum, similar to the Copal.

Among the more recent in formation of fossil vegetables, are the bituminized woods; these are often buried to great depths by diluvian action, but are never found in perfect rock. The most remarkable instance of this kind is at Bovey-Heathfield, in England, and beneath is found the retinasphaltum, that seems to be no more than the expressed viscorous juice of the trees. Coal is a similar formation, but due to a more ancient period. The mines of Pennsylvania occasionally furnish specimens, in which the fibre of the wood is as distinctly visible as in recently prepared charcoal. However these vast beds may have been formed, no doubt whatever can exist in respect to their vegetable origin.

Among animal remains found in the fossil state, shells and zoophytes are the most abundant. They form the principal parts of rocks which often occupy considerable districts. They are most frequent in calcareous strata, from the transition limestones to the highest of the marles. A remarkable fact is observed in respect to these shells, and the other fossils which accompany them; those which are found in the oldest, or transition formations, are more different from those that now exist, than those in the more modern deposits. Thus the transition limestones and slates contain terrebratulites, with encrinites, pentacrinites, and trilobites; in those of the submedial and medial series we find belemnites and the cornu ammonis; many of which are extinct genera, and some of which are of families that are no longer found living on our globe, while even where the genus is now to be met with, the species at least has become extinct; while in the latest of the tertiary or superior formations, we find ostracites, pectinites, buccinites, chamites, and many other genera that are still abundant, and even types of living species.

By far the greater part of the animals whose remains are found in the older strata are aquatic, and the vast extents over which they are distributed, show, that the waters must at one time have covered a very great proportion of what is now dry land. Nor has this change been produced by any gradual subsidence, for we find no coincidence in the levels of those portions of the land that contain similar fossils; some for instance are still lower than the level of the present ocean; others, again, of similar character, rest upon the tops or sides of the highest mountains. In Europe, the tops of the highest of the Pyrenees, rising 11000 feet above the level of the sea, are of limestone, containing numerous fossil remains, while Humboldt found a rock, similarly characterized, among the Andes, at the height of 14000 feet.

The ancient philosophers, who, in other departments of physical science, were far behind the moderns, seem in this alone to have pursued a process of inductive reasoning, which led to results far more accurate than any attained by the moderns, until within a very few years. The dogmatism which determined to find in every fossil aquatic remain a proof of the particular Noachic deluge, and the timidity of those whose researches had made them better informed, left the world wholly in the dark as to the real inferences to be drawn from a study of the structure of the earth; but what modern geologist could better express what are now admitted opinions, than the words which the Roman poet puts in the mouth of Pythagoras.

"Vidi ego, quod quondam fuerat solidissima tellus,
Esse Fretum. Vidi factas ex aequore terras:
Et procul a pelago conchae jacuere marinae;
Et vetus inventa est in montibus anchora summis.
Quodque fuit campus, vallem decursus aquarum
Fecit: et eluvie mons est deductus in aequor:
Eque paludosa siccis humus aret arenis;
Quaeque sitim tulerant, stagnata paludibus hument.
Hic fontes Natura novos emisit, at illie
Clausit: et antiquis concussa tremoribus orbis
Flumina prosiliunt; aut exaecata resident."

The order in which fossil remains are found to succeed each other in the successive formations that are to be traced from the oldest rocks to the diluvial deposit, are well illustrated in the words of a late distinguished philosopher, whom we shall quote.

"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 the next in order; the bones of fishes and oviparous
reptiles exist in the following class; the remains of birds,
with those of the same genera 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 diluvial formations, that the remains of animals such as
now people the globe are found, with others of extinct species.
But in none of these formations, whether called secondary,
tertiary, or diluvial, have the remains of man, 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 man as the master of the
globe, are as certain as the destruction of a former and
different order, and the extinction of a number of living
forms, which have 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 most
recently deposited, these remains occur but rarely, and with
abundance of distinct species;--there seems, as it were, a
gradual approach to the present system of things, and a
succession of destructions and creations preparatory to the
existence of man."

We have stated that the zoophytes and shell-fish have left the most numerous fossil remains. Those of other families are not however rare. Fish, for instance, are found in great abundance, near Glarus in Switzerland, in clay slate; in Germany, at Papenheim, in a slaty marle, in the cupriferous slate of Eisleben, in the fetid limestone of Oehningen. They are also found in Egypt, and we have specimens of the same sort from Lyria, in a limestone apparently belonging to the oolitic or Jura formation. China and the coast of Coromandel have also fossils of this sort, but by far the greatest quantity have been procured from Mount Bolea, near Verona. A splendid suite from the last locality are to be seen in the Gibbs' Cabinet at New-Haven. Besides the impressions of entire fish, separate portions are very abundant, and perhaps the most frequent of these are the teeth of sharks, which are sometimes of a magnitude vastly greater than those of any living species. Animals of the class of amphibia appear not to have existed until after the aera that gave birth to fish. The oldest are probably the tortoises, of which a specimen has been found in sandstone near Berlingen. They have also been found in England, in the Netherlands near Brussels, at Aix in Provence, and in the quarries near Paris. The most remarkable fossils of this class belong, however, to the lizard family. Of these the most remarkable are the plesiosaurus, the megalosaurus, the iguanodon, and the crocodile of Maestricht, all belonging to extinct species.

The marine animals that are met with in a fossil state, are in great part foreign to the climates in which they are found buried. It has been shown that the fish of Bolea have their nearest living prototypes in the seas of Otaheite. The perpites of Gothland have been supposed to be petrifactions of the medusae of India. The madrepores, so abundant in Russia and in the frozen deserts of Siberia, only live now in seas within the tropics. Shells analogous to a great part of those found fossil in England, are only to be seen in the Atlantic, in a living state, on the coasts of Florida and Cuba. A shell-formed fossil at Havre is only to be met with recent at Amboyna.

Of the shells found in Italy, fossil in the sub Appenine hills, many are common to the Mediterranean and the Indian oceans. But while those in the fossil slate and the recent specimens from the tropics correspond in size, individuals of the same species from the Mediterranean are dwarfish and degenerate.

Thus then the remains of aquatic and amphibious animals appear to confirm the conclusion drawn from vegetable fossils, that a climate of temperature as elevated as that now found in the tropics, once extended into high northern latitudes. It has been seen that the fossil remains and impressions of shells have been found at great heights upon the sides, and even upon the tops of mountains; and that in the older of the strata no trace is to be found of any but aquatic animals. Thus before our existing mountains and the minerals they contain had arisen above the general surface; before diluvial and alluvial deposits, or even the great formations of sandstone and conglomerate had arisen from their disintegration, the globe was covered, in a great degree, and as it appears from considerations we have not space to enter into, by various successive eruptions, with waters, sometimes fresh, sometimes saline. These waters have, it could be readily made to appear, often rested long on the surface in a quiet state, after having been in violent agitation; and long ages of tranquillity have been succeeded and closed by convulsions of the most violent character.

In all the regularly stratified formations, animals of the mammiferous or cetaceous classes are wholly wanting; at least we have no proof that can be relied upon of any having been found in formations which took place prior to the last great deluge, that covered so much of the land with diluvium. In this last formation, however, they are often found in great abundance. Some of them are of recent, others of extinct species. Among the most remarkable of the latter are, the palaeotherium, and anoplotherium, found near Paris; the megalonyx, an animal of the sloth genus, but of the size of an ox, found in Virginia; a still larger sloth, called the megatherium, found near Buenos Ayres; the fossil elephant, as different from the living elephants of India or Africa, as the horse is from the ass, and which has been found in Europe, in Asia, and in America. The mastodon, of which several species have been discovered on the banks of the Hudson, in Kentucky, in Louisiana, in the plains of Quito, in France, and finally on the borders of the Irrawaddy.

The bones of rhinoceroses, bears, elephants, and hyaenas, have been found mixed in confusion in caverns; and it has been shown by Buckland that the latter animal had inhabited these caverns, and drawn thither the carcasses of the others as his prey, in one of the most perfect inductive arguments which has been produced, since Bacon propounded the rules of that species of reasoning.

"The moveable earths that fill the bottoms of valleys, and
which cover the surface of great plains, have furnished us in
the above two orders, of pachidermata and elephants, the bones
of twelve species, to wit: one rhinoceros, two hippopotami, two
tapirs, an elephant, and six mastodons. All these twelve
species are now absolutely extinct in the climates in which
their bones are found. The mastodons alone may be considered as
forming a separate genus, now unknown, but closely approaching
to the elephant. All the others belong to genera now existing
in the torrid zone. Three of these living genera are now found
only in the ancient continent, to wit: the rhinoceros, the
hippopotami, and the elephant; the fourth, that of the tapirs,
only exist in the new. The distribution of the fossil species
is different; the tapirs have been found only upon the old
continent, while elephants have been discovered in the new."

The fossil species, although belonging to known and existing _genera_, are essentially different in _species_ from those which now live upon the earth. The former are not mere varieties, but have marked specific differences. This at least is beyond all doubt in respect to the smaller of the hippopotami, and the gigantic tapir, as well as the fossil rhinoceros, and is extremely probable in respect to the elephant and the smaller tapir. If there be any question of the fact, it is only in respect to the greater hippopotamus.

"These different bones are buried in all different places in
beds that resemble each other. They are often mixed
indiscriminately with those of other animals, identical with
those which exist at present. These beds are generally
moveable, sandy, or marly, and always within a short distance
of the surface. It is therefore probable that these bones have
been enveloped by the last catastrophe of the globe. In a great
number of places, they are accompanied by the accumulated
spoils of marine animals; in other places, but these are less
numerous, the remains of marine animals are not found, and
sometimes the sand or marle that covers them contains only
fresh-water shells. Although a small number of shells attached
to fossil bones indicate that, they have remained some time
under water, yet is there no authentic account of their having
been found covered with regular stony beds, filled with marine
remains, nor, in consequence, is there any proof of the sea
having made a long and peaceable stay above them.

"The catastrophe that has covered them, would appear then to
have been a great marine inundation, of no long duration, were
it not that they are found upon the tops of high mountains,
whither the waters of our present ocean could never have
reached in their most violent agitations. On the other hand,
these bones presenting no appearance of having been rolled,
being occasionally only fractured, as the remains of our
present domestic animals may occasionally be, and being
sometimes found in entire skeletons, and accumulated as if in a
common cemetery, demonstrate that the living beings to which
they have belonged, must have met their fate in the very parts
of the globe in which we now find the fossil monuments of their
existence."

All the animals of which we have particularly spoken, are of genera now only found in the torrid zone, and the abundance of food which their great size would have caused them to require, renders their existence in numbers only possible in a warm climate. Their remains are, however, found in almost polar regions, whence we obtain a third link in the chain of evidence, that before the last great catastrophe to which the globe was subjected, its surface must have been warmer than at present.

We have seen in a former place, that such a change of temperature may have gradually occurred in consequence of a cooling of the external surface of the globe by an excess of its radiation above the quantity of heat received from the sun. The final cooling of its solid crust, down to the mean temperature at which we now find it, might, as is obvious, have been effected by a great irruption of waters, like that of which we have distinct evidence in the diluvial deposits, and the animal remains upon its surface. From that time, a state of equilibrium in the action of solar and terrestrial radiation having been attained, while the mean temperature still continues to depend upon the internal structure and nature of the globe, the distribution of heat upon the surface, and the vicissitudes of the seasons, have been solely influenced by the varying relation between these two radiations, which if equal to each other in their total amounts, differ in every different latitude, for every successive day in the year, and during each varying hour of the day.

It has been attempted to explain this change that has unquestionably taken place in the temperature of climate, by conceiving a change in the situation of the earth's axis. This hypothesis, however, is shown to be untenable by the calculations of physical astronomy: no other cause then remains but an actual change in the condition of the earth itself.

The most remarkable of all the phenomena which the earth presents, are the great changes of weight that have taken place in identical formations which must have arisen from the prevalence of water, and therefore nearly if not exactly upon the same level. The primitive or lowest stratified rocks, probably had not water for their cause; still, however, they must have been in the fluid state, and these are not only found beneath all other rocks, and in the lowest places to which the industry of man has penetrated, but they also rise and form the greatest part in bulk of many of the highest mountains; indeed, if we except volcanic mountains, of all the more elevated masses. The transition and secondary formations are subject to similar although less changes of level, rising, as has been seen, to the tops of the Pyrenees, and to even a greater height on the sides of the Andes. The tertiary or superior formations are found in Italy and Sicily, forming mountains several thousand feet in height, while the latest of all, the diluvial with its embedded mammalia, exists in the lofty table land of Quito. The inference is irresistible, that we do not now find these deposits at the levels where they were left by the ocean, as in the case of the primitive rocks by their own crystallization from a fluid state, but that they have been altered in their positions by actions of a character totally distinct from that by which they were originally formed.

This inference is still further confirmed by the great and sudden changes of level that are frequently to be seen in similar strata, faults, as they are styled by miners, in which the same bed has its level sometimes changed hundreds, nay even thousands of feet. These faults, if in greatest abundance in the more ancient rocks, are to be found even in the newest, and sometimes affect several formations incumbent on each other, of ages the most different. Thus, then, we have distinct and conclusive evidence, that as we inferred from theory, the solid crust of the globe has been shattered and fractured repeatedly, and at all the different epochs of its history. This fracturing and cracking we have shown, must, in conformity with strict mechanical laws, have been attended with the rise of the molten liquid from beneath, which ought in some cases to have formed veins and dykes, in the places where the fractures occurred. It is however possible, that the rise of the fluid from beneath, may not have taken place where the pressure occurred; but it would then have been compelled by hydrostatic pressure, to issue at some other point, breaking and tearing the weaker parts of the solid crust, in order to afford itself a vent.

The latter class of phenomena are still in action, and we have evident traces of their occurrence in all the different stages of the world's existence; of the former it will also be seen there is conclusive evidence.

The visible effects of a subterranean heat, are most frequently met with at the present day in the form of volcanoes. Of these, there are not only a great number in activity, but there are still more that have been certainly active since the last great change that the surface of the earth has undergone.