reasoning, and proceeds on the system of absolute identity or of
pantheism, attributes the production of all phenomena, or which,
in the eyes of its supporters, is the same thing, all beings, to
polarization, such as is manifested by the two electricities; and
denominating every kind of opposition or difference, whether of
situation, of nature, or of function, by the title of Polarisation,
opposes to each other, in the first place, God and the universe;
then, in the universe, the sun and the planets; next, in each planet,
the solid and the liquid; and, pursuing this course, changing its
figures and allegories according to its necessities, at length
arrives at the last details of organic species[24].
It must, however, be observed, that these are what may be termed
extreme examples, and that all geologists have not carried the
extravagance of their conceptions to such a length as those which
we have just cited. Yet, among those who have proceeded with
more caution, and have not searched for geological causes beyond
the limits of physical and chemical science, much diversity and
contradiction still prevail.
_Diversities of all the Systems._
According to one system, every thing has been successively
precipitated by crystallization, and deposited nearly as it exists at
present; but the sea, which covered all, has gradually retired[25].
According to another, the materials of which the mountains consist,
are incessantly worn down and carried off by the rivers to be
deposited at the bottom of the sea, where they are heated under an
enormous pressure, and form strata, which are one day to be violently
lifted up by the heat which consolidates them[26].
A third supposes the fluid divided into a multitude of lakes, placed,
like the seats of an amphitheatre, above each other, which, after
having deposited our shelly strata, have successively broken their
dikes, to descend and fill the basin of the ocean[27].
According to a fourth, tides of seven or eight hundred fathoms depth
have carried off, from time to time, the matter lying at the bottom
of the sea, and have thrown it, in the form of mountains and hills,
upon the original valleys or plains of the continent[28].
A fifth makes the various fragments of which the earth is composed,
fall successively from heaven, in the manner of meteoric stones,
bearing the impress of their foreign origin in the unknown beings
whose remains they contain[29].
A sixth represents the globe as hollow, and places within it a
loadstone nucleus, which is transported from one pole to the other,
by the attraction of comets, carrying along with it the centre of
gravity, and the mass of waters at the surface; thus alternately
drowning the two hemispheres[30].
We might mention twenty other systems, as different from one another
as those enumerated. And to prevent mistake, we may here state, that
our intention is not captiously to criticize or find fault with their
authors; on the contrary, we admit that these ideas have generally
been conceived by men of intellect and knowledge, who were not
ignorant of facts, several of whom had even travelled extensively for
the purpose of examining them, and who, in this manner, made numerous
and important additions to science.
_Causes of these differences._
Whence comes it, then, that there should be so much contrariety
in the solutions of the same problem, that are given by men who
proceed upon the same principles? May not this have been occasioned
by the conditions of the problem never having been all taken
into consideration at once; by which it has remained hitherto
indeterminate, and susceptible of many solutions,--all equally good,
when such or such conditions are abstracted; and all equally bad,
when a new condition comes to be known, or when the attention is
directed to some condition which had been formerly neglected?
_Nature and Conditions of the Problem._
To quit the language of mathematics, it may be asserted, that almost
all the authors of these systems, confining their attention to
certain difficulties which struck them more forcibly than others,
have endeavoured to solve these in a manner more or less plausible,
and have left unnoticed others, equally numerous, and equally
important. For example, the only difficulty with one consisted in
explaining the changes that had taken place in the level of the
sea; with another, it consisted in accounting for the solution of
all terrestrial substances in one and the same menstruum; and with
a third, in shewing how animals that were believed to be natives of
the torrid zone could live in the frigid zone. Exhausting all the
powers of the mind upon these questions, they conceived that they
had done every thing that was necessary when they had contrived some
method of answering them; and yet, while they neglected all the other
phenomena, they did not always think of determining with precision
the measure and limits of those which they had endeavoured to explain.
This is peculiarly the case with regard to the secondary formations,
which constitute, however, the most important and most difficult part
of the problem. During a long time, all that was done with respect
to these, consisted of feeble attempts to determine the order of
superposition of their strata, and the connections of these strata
with the species of animals and plants whose remains they contain.
Are there certain animals and plants peculiar to certain strata, and
not found in others? What are the species that appear first in order,
and what those which succeed? Do these two kinds of species sometimes
accompany each other? Are there alternations in their appearance;
or, in other words, do the first reappear a second time, and do the
others then disappear? Have these animals and plants all lived in the
places where their remains are found, or have they been transported
thither from other places? Do they all live at the present day in
some part of the earth, or have they been partially or totally
destroyed? Is there any constant connection between the antiquity of
the strata and the resemblance, or non-resemblance, of the fossils
contained in them to the animals and plants which now exist? Is there
any connexion, in regard to climate, between the fossils and such
living beings as resemble them most? May it be concluded, that the
transportation of these living beings, if such a thing ever happened,
has taken place from north to south, or from east to west; or were
they irregularly scattered and mingled together; and can the epochs
of these transportations be determined by the characters which they
have impressed upon the strata?
What can be said regarding the causes of the existing state of the
globe, if no reply can be made to these questions,--if there be no
sufficient grounds to determine the choice between answering in the
affirmative or negative? It is but too true, that, for a long time,
none of these points was satisfactorily determined; and scarcely
even would geologists seem to have had any idea of the propriety of
clearing them up before constructing their systems.
_Reason for which the Conditions of the Problem have been neglected._
The reason of this strange procedure will be discovered, when
we reflect, that all geologists have hitherto been, either mere
cabinet naturalists, who had themselves paid little attention to the
structure of mountains, or mere mineralogists, who had not studied
in sufficient detail the innumerable varieties of animals, and the
infinite complication of their various parts. The former of these
have only constructed systems: the latter have furnished excellent
observations, and have laid the foundation of true geological
science; but have been unable to complete the edifice.
_Progress of Mineral Geology._
The purely mineral part of the great problem of the Theory of the
Earth has been investigated with admirable care by Saussure, and has
been since carried to an astonishing degree of development by Werner,
and by the numerous enlightened pupils of his school.
The former of these celebrated men, by a laborious investigation
of the most inaccessible districts, continued for twenty years, in
which he examined the Alps on all sides, and penetrated through
all their defiles; has laid open to our view the entire disorder
of the primitive formations, and has distinctly traced the limits
by which they are distinguished from the secondary formations. The
other, taking advantage of the numerous excavations made in the most
ancient mining district in the world, has fixed the laws by which the
succession of the strata are regulated, pointing out the relative
antiquity of these strata, and tracing each of them through all its
metamorphoses. It is from him, and from him alone, that we date the
commencement of real geology, in so far as concerns the mineral
nature of the strata: but neither he nor Saussure have determined the
fossil organic species occurring in each kind of stratum, with the
accuracy which has become necessary, now that the number of animals
already known is so great.
Other naturalists, it is true, have examined the the fossil remains
of organised bodies; they have collected and figured them by
thousands, and their works will serve as so many precious collections
of materials. But, considering these animals and plants more with
reference to their own nature, than as connected with the theory of
the earth; or regarding these petrifactions as curiosities, rather
than as historical documents; or, lastly, contenting themselves with
practical explanations regarding the position of each fragment,
they have almost always neglected to investigate the general laws
affecting the geological position of organic remains, or their
connection with the strata.
_Importance of Fossil Remains in Geology._
And yet, the idea of such an investigation was very natural; for
it is abundantly obvious, that it is to these fossil remains alone
that we owe even the commencement of a theory of the earth, and
that, without them, we should perhaps never have even suspected that
there had existed any successive epochs, and a series of different
operations, in the formation of the globe. By them alone we are,
in fact, enabled to ascertain, that the globe has not always had
the same external crust; because, we are thoroughly assured, that
the plants and animals must have lived at the surface before they
had thus come to be buried deep beneath it. It is only by analogy
that we have been enabled to extend to the primitive formations,
the conclusion which is furnished directly for the secondary by the
organic remains which they contain; and if there had only existed
formations in which no fossil remains were inclosed, it could
never have been shewn that these formations had not all been of
simultaneous origin.
It is also by means of the organic remains, slight as is the
knowledge we have hitherto acquired of them, that we have been
enabled to discover the little that we yet know respecting the nature
of the revolutions of the globe. From them we have learned, that
the strata in which they are buried have been quietly deposited in
a fluid; that their variations have corresponded with those of the
fluid in question; that their being laid bare has been occasioned by
the transportation of this fluid to some other place; and that this
circumstance must have befallen them more than once. Nothing of all
this could have been known with certainty, had no fossil remains
existed.
The study of the mineral part of geology, though not less necessary,
and even of much more utility to the practical arts, is yet much less
instructive with reference to the object of our present inquiry.
We remain in utter ignorance respecting the causes which have given
rise to the variety in the mineral substances of which the strata are
composed. We are even ignorant of the agents which may have held some
of these substances in solution; and it is still disputed, respecting
several of them, whether they have owed their origin to water or to
fire. After all, philosophers are only agreed on one point, which is,
that the sea has changed its place; and how should this have been
known, unless by means of the fossil remains?
The organic remains, therefore, which have given rise to the
theory of the earth, have, at the same time, furnished it with its
principal illustrations;--the only ones, indeed, that have as yet
been generally acknowledged.
It is this consideration which has encouraged us to investigate the
subject. But the field is vast; and it is but a very small portion
of it that could be cultivated by the labour of a single individual.
It was necessary, therefore, to select a particular department; and
the choice was soon made. The class of fossil remains which forms
the subject of this work, engaged our attention at the very outset,
because it appeared to us to be that which is the most fertile in
precise results, and yet, at the same time, less known, and richer in
new objects of research[31].
_High importance of the Fossil Bones of Quadrupeds._
It is obvious, in fact, that the fossil bones of quadrupeds must lead
to more accurate conclusions than any other remains of organized
bodies, and that for several reasons.
In the first place, they indicate much more clearly the nature of
the revolutions to which they have already been subjected. Shells
certainly announce the fact, that the sea has once existed in the
places where they have been formed; but the changes which have taken
place in their species, when rigorously inquired into, may have
arisen from slight changes in the nature of the fluid in which they
lived, or merely in its temperature. They may even have been produced
by causes still more accidental. We can never be perfectly assured
that certain species, and even genera, inhabiting the bottom of the
sea, and occupying certain fixed spaces, for a longer or shorter
time, may not have been driven away and supplanted by other species
or genera.
In regard to quadrupeds, on the contrary, every thing is precise. The
appearance of their bones in strata, and still more of their entire
carcases, announces, either that the stratum itself which contains
them has, at a former period, been laid dry, or, at least, that dry
land must have existed in its neighbourhood. Their disappearance
renders it certain, that this stratum has been inundated, or that the
dry land in question has ceased to exist. It is from them, therefore,
that we learn with perfect certainty the important fact of repeated
irruptions of the sea, which the shells and other marine productions
could not of themselves have proved; and it is by a careful
investigation of them, that we may hope to ascertain the number and
the epochs of these irruptions.
Secondly, The nature of the revolutions which have altered the
surface of the globe, must have exerted a more powerful action
upon terrestrial quadrupeds, than upon marine animals. As these
revolutions have consisted chiefly of changes in the bed of the
sea, and as the waters must have destroyed all the quadrupeds which
they reached, if their irruption was general, it would necessarily
have destroyed the entire class; or if it only overwhelmed certain
continents at one time, it would at least have destroyed the species
peculiar to those continents, without having the same effect upon the
marine animals. On the other hand, millions of aquatic animals would
have been left dry, or buried under newly-formed strata, or thrown
violently on the coasts; while their races would still have been
preserved in some more peaceful parts of the sea, whence they might
again be propagated after the agitation of the waters had ceased.
Thirdly, This more complete action is also more easily ascertained.
It is more easy to demonstrate its effects, because, the number of
quadrupeds being limited, and the greater part of their species, at
least the large ones, being known, we have more means of determining
whether fossil bones belong to them, or to a species that is now
lost. As, on the other hand, we are very far from being acquainted
with all the testaceous animals and fishes which inhabit the sea,
and as we are still probably ignorant of the greater number of those
which live in deep water, it is impossible to know with certainty,
whether a species which occurs in a fossil state, may not still exist
somewhere alive. And hence, we see naturalists persisting in giving
the name of pelagic shells, that is to say, shells inhabiting the
open sea, to the belemnites, cornua-ammonis, and other testaceous
remains, which have hitherto been found only in the older strata;
meaning by this, that if they have not yet been discovered in a
living state, it is because they inhabit the depths of the sea, far
beyond the reach of our nets.
_Small probability of discovering New Species of large Quadrupeds._
Naturalists, certainly, have not yet explored all the continents, nor
do they even know all the quadrupeds which inhabit the countries that
they have explored. New species of this class are discovered from
time to time; and those who have not examined with attention all the
circumstances belonging to these discoveries, might also imagine that
the unknown quadrupeds, whose bones are found in our strata, may
remain to this day concealed, in some islands not yet discovered by
navigators, or in some of the vast deserts which occupy the middle of
Asia, Africa, the two Americas, and New Holland.
However, if we carefully examine what kinds of quadrupeds have been
recently discovered, and in what circumstances they have been found,
we shall see that there is little hope of our ever finding alive
those which have hitherto been observed only in a fossil state.
Islands of moderate extent, and at a considerable distance from
the continents or large islands, possess very few quadrupeds, and
these, for the greater part, of diminutive size. When they happen
to contain any of the larger species, these must have been carried
to them from other countries. Bougainville and Cook found no other
large quadrupeds than hogs and dogs in the South Sea Islands; and the
largest species of the West India Islands was the _agouti_.
It is true that the great continents, such as Asia, Africa, the two
Americas, and New Holland, possess large quadrupeds, and, generally
speaking, contain species peculiar to each; insomuch, that whenever
large countries of this description have been discovered, which
their situation has kept isolated from the rest of the world, the
class of quadrupeds which they contained has been found entirely
different from any that existed elsewhere. Thus, when the Spaniards
first penetrated into South America, they did not find a single
species of quadruped the same as any of Europe, Asia, or Africa.
The puma, the jaguar, the tapir, the cabiai, the llama, the vicuna,
the sloths, the armadilloes, the opossums, and the whole tribe of
sapajous, were to them entirely new animals, of which they had no
idea. Similar circumstances have recurred in our own time, when
the coasts of New Holland and the adjacent islands were first
explored. The various species of kangaroo, phascolomys, dasyurus, and
perameles, the flying phalangers, the ornithorynchi and echidnæ, have
astonished naturalists by the strangeness of their conformations,
which presented proportions contrary to all former rules, and were
incapable of being arranged under any of the systems then in use.
If there yet remained some great continent to be discovered, we might
still hope to become acquainted with new species, among which there
might be found some having more or less similarity to those of which
we have discovered the remains in the bowels of the earth. But it is
sufficient to cast a glance over the map of the world, and see the
innumerable directions in which navigators have traversed the ocean,
in order to be satisfied that there remains no other large land to
be discovered, unless it may be situated towards the South Pole,
where the existence of life would necessarily be precluded by the
accumulation of ice.
Hence, it is only from the interior of the large divisions of the
world, that we can have any hope of still procuring quadrupeds
hitherto unknown. But a little reflection will be sufficient to
convince us, that our expectations from this source have as little
foundation as from that of the islands.
Doubtless, the European traveller cannot easily traverse vast extents
of countries, which are either destitute of inhabitants, or are
peopled only with ferocious tribes; and this is more especially true
with regard to Africa. But there is nothing to prevent the animals
themselves from roaming over these countries in all directions, and
penetrating to the coasts. Even when there may be great chains of
mountains between the coasts and the deserts of the interior, they
must always be broken in some places to allow the rivers to pass
through; and, in these burning deserts, the quadrupeds naturally
follow the banks of rivers. The inhabitants of the coasts also ascend
these rivers, and soon become acquainted with all the remarkable
species which exist even to their sources, either from personal
observation, or by means of intercourse with the inhabitants of
the interior. At no period, therefore, could civilized nations have
frequented the coast of a large country for any considerable length
of time, without gaining some tolerable knowledge of such of the
animals which it contained as were remarkable for their size or
configuration.
This reasoning is confirmed by well known facts. Although the
ancients never passed the mountains of Imaus, or crossed the Ganges,
in Asia; and, although they never penetrated very far beyond Mount
Atlas, in Africa; yet were they, in reality, acquainted with all the
large animals of these two divisions of the world; and, if they have
not distinguished all the species, it was not because they had not
seen them, or heard them spoken of by others, but because the mutual
resemblances of some of these species caused them to be confounded
together. The only important exception which can be opposed to this
assertion, presents itself in the Tapir of Malacca, recently sent
home from India by two young naturalists, pupils of mine, Messrs
Duvaucel and Diard, and which in fact is one of the most interesting
discoveries with which Natural History has been enriched in these
latter times.
The ancients were perfectly acquainted with the Elephant; and the
history of that quadruped is given more accurately by Aristotle than
by Buffon. They were not even ignorant of some of the differences
which distinguish the elephants of Africa from those of Asia[32].
They knew the two-horned Rhinoceros, which has never been seen alive
in modern Europe. Domitian exhibited it at Rome, and had it stamped
on his medals, which have been very well described by Pausanias.
The one-horned Rhinoceros, distant as was its country, was equally
known to them. Pompey shewed one at Rome; and Strabo has accurately
described another which he saw at Alexandria[33].
The Rhinoceros of Sumatra described by Mr Bell; and that of Java,
discovered and sent home by Messrs Duvaucel and Diard, do not appear
to inhabit the continent. Hence, it is not surprising, that the
ancients should have been ignorant of them; besides, they probably
would not have distinguished them from the others.
The Hippopotamus has not been so well described as the preceding
animals; yet very exact representations of it have been left by the
Romans in their monuments relative to Egypt, such as the statue of
the Nile, the Palestrine pavement, and a great number of medals.
In fact, this animal was repeatedly seen by the Romans; having been
exhibited by Scaurus, Augustus, Antoninus, Commodus, Heliogabalus,
Philip, and Carinus[34].
The two species of Camel, the Bactrian and Arabian, are both very
well described and characterized by Aristotle[35].