A

DISCOURSE

ON THE

REVOLUTIONS OF THE SURFACE OF
THE GLOBE,

AND THE CHANGES THEREBY PRODUCED IN

THE ANIMAL KINGDOM.

______________

IN my work on Fossil Remains, I proposed to
determine to what animals those fragments of bones
should be assigned which occupy the superficial strata
of the globe. It was attempting to traverse the whole of
a region of which as yet the first approaches were
scarcely known. An antiquary of a new stamp, it was
necessary at the same time to restore these monuments
of past revolutions, and to detect their meaning: I had
to collect and arrange in their original order the
component relics; to remodel the creatures to whom
the fragments belonged; to reproduce them in their just
proportions and with their proper characteristics; and
then to compare them with those beings now existing:
— an art almost unknown, and which implies a science
scarcely before even glanced at — that of the laws
which preside

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ON THE REVOLUTIONS OF

at the coexistence of the forms of the various parts of
organized beings. For such an attempt it was necessary
to prepare myself by long and indefatigable researches
into the structure of living animals; by asurvey of
nearly the whole mass of created beings now existing,
which alone could lead me to a certain and determinate
result in my speculations on the ancient creation: this
would at the same time afford me a great result of
rules, and affinities not less useful, and the whole
animal kingdom would thus, in some measure, become
subjected to new laws, resulting from this essay on a
small portion of the theory of the earth.
I was supported in my twofold labours by the
interest which it seemed to evince both for anatomy,
the essential basis of all those sciences which treat of
organized bodies; and for the physical history of the
globe, the foundation of mineralogy, of geography,
and, we may say, of the history of man, and of all
which it most imports him to know in relation to
himself.
If we are interested in tracing out the nearly effaced
vestiges of the infancy of our species, in so many
nations utterly extinct, why should we not seek to
discover, in the obscurity which envelopes the infancy
of the earth, relics of revolutions long anterior to the
existence of all nations? We admire that power of the
human mind, the exercise of which has enabled us to
ascertain those motions of the planets, which Nature
seemed for ever to have held from us; genius and
science have soared beyond the limits of space; some
observations, developed by reason, have detected the
mechanism of the world. Would it not be some renown
for a man, in like manner, to penetrate beyond the
limits of time, and to discover, by research and
reflection, the

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THE SURFACE OF THE GLOBE

history of this world, and of a succession of events
which preceded the birth of the human race?
Astronomers have advanced in science more rapidly
than naturalists; and the present state of the theory of
the earth somewhat resembles that of the period when
certain philosophers believed heaven tobe formed of
polished freestone, and the moon in size like the
Peloponnesus; but, after Anaxagoras, have arisen
Copernicus and Kepler, who paved the way for a
Newton; and why should not natural history one day
boast also of her Newton?

PLAN.

It is the plan and result of my labours on fossil
bones, which I particularly intend to lay before you in
this discourse: I shall also attempt to trace a rapid
sketch of the means employed down to the present time
to discover the history of the revolutions of the globe.
The facts which I have been enabled to arrive at form
certainly but a very small portion of those of which
doubtlessly this history of antiquity was composed; but
many of them lead to decisive results, and the severe
method which I have exercised in deciding on them,
gives me reason to believe that they may be received as
assured data, and will constitute an epoch in the
science. I trust their novelty will be my excuse, if I
ask for them the undivided attention of my readers.
My first object will be to show the relation between
the history of fossil bones of terrestrial animals, and
the theory of the earth, and the motives which in this
respect give it a peculiar importance. I shall then
unfold the principles of deciding on these bones, or in
other words, of ascertaining a

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ON THE REVOLUTIONS OF

genus, and distinguishing a species, by a single
fragment of bone; an art on the certainty of which
rests that of the whole of my labours. I shall slightly
notice new species and genera formerly unknown,
which I have discovered by the application of these
principles, as well as the different kinds of earth which
contain them; and, as the difference between these
species and those of' the present day is confined to
certain limits, I shall show that these limits much
exceed those which at present distinguish the varieties
of the same species. I shall make known how these
varieties are limited, either by the influence of time,
climate, or domesticity. I shall thus be enabled to
conclude, and enable my readers to arrive at a similar
conclusion, that there must have been remarkable
events to have effected the great differences that I
have detected. I shall detail the peculiar modification
which my researches have enabled me to introduce into
the opinions at present entertained respecting the
revolutions of the globe; and finally, I shall examine
how far the civil and religious history of nations agree
with the results of my observations on the physical
history of the earth, and with the probabilities which
these observations give rise to concerning the period
when human societies found fixed dwellings and fields
capable of cultivation; and when, consequently, they
received a settled permanent form.

FIRST APPEARANCE OF THE EARTH.

When the traveller passes over those fertile plains
where the peaceful waters preserve, by their regular
course, an abundant vegetation, and the soil of which,
crowded by an extensive population, enriched

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THE SURFACE OF THE GLOBE

by flourishing villages, vast cities, and splended
monuments, is never disturbed but by the ravages of
war, or the oppression of despotism, he is not inclined
to believe that nature has there had her intestine war;
and that the surface of the globe has been overthrown
by revolutions and catastrophes; but his opinions
change as he begins to penetrate into that soil at
present so peaceful, or as he ascends the hills which
bound the plain; they extend as it were with the
prospect, they begin to comprehend the extent and
grandeur of those events of ages past as soon as he
ascends that more elevated chains of which these hills
form the base, or, in following the beds of those
torrents which descend from these chains, he penetrates
into their interior.

FIRST PROOFS OF REVOLUTIONS.

The strata of the earth, the lowest and most level,
only show, even when penetrated to very great depths,
horizontal layers of matter more or less varied, which
contain countless marine productions. Similar layers
and similar productions form the hills to very
considerable heights. Sometimes the shells are so
numerous that they form by themselves the entire soil;
they are found at heights greatly above the level of the
sea, and where at the present day no sea could reach
from existing causes; they are not only imbedded in
light sand, but the hardest stones often incrust them
and are everywhere penetrated by them. Every part of
the world, both hemispheres, all the continents, all the
islands of any extent, afford the same phenomenon.
The time is past when ignorance could assert that these
relics of organic bodies were but freaks of nature,

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ON THE REVOLUTIONS OF

productions engendered in the bosom of the earth by
its innate creative power; and the efforts of
metaphysicians will not suffice to establish such
assertions. A minute investigation of the formation of
these deposites, of their contexture, even of their
chemical composition, does not detect the least
difference between the fossil shells and those produced
from the sea; their conformation is not less perfect; we
do not observe either the marks of friction or fracture,
evincing violent removal; the smallest of them
preserve their most delicate parts, their finest points,
their most minute indications; thus they have not only
lived in the sea, but have been deposited by the sea;
the sea has left them in the places where they are
found; but the sea has for a time remained in these
places, it has remained there sufficiently long and
undisturbedly to be enabled to form those deposites so
regular, so thick, so extensive, and so solid, which
compose these layers of aquatic animals. The basis of
the sea has then experienced a change either in extent
or situation. What a result from the first examination,
and the most superficial observation!
The traces of revolutions become more striking
when we ascend higher, when we approach closer to
the foot of the great chains of mountains.
There are besides banks of shells; we remark them
of great thickness and solidity; the shells are there
equally numerous, equally well preserved, but they are
not the same species; the layers which contain them are
no longer generally horizontal; they lie obliquely,
sometimes nearly perpendicular; instead of digging
deeply, as in the plains and broad hills, to ascertain the
order of the banks, we here have them side-ways, in
following the valleys formed by the convulsions which
have rent them asunder;

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THE SURFACE OF THE GLOBE

immense masses of their remains constitute at the foot
of their pinnacles heavy mounds, the height of which
is increased by every thaw and every storm.
And these upright (redressés) banks, which form the
crests of the secondary mountains, are not placed on
the horizontal banks of the hills which form their
lower ascents; on the contrary, they are sunk beneath
them. These hills rest on their declivities. When the
horizontal layers in the vicinity of these mountains
with oblique strata, are laid open, we again find the
layers oblique in the excavation; sometimes even when
the oblique layers are not very much elevated, their
summit is crowned with horizontal layers. The oblique
layers are then more ancient than the horizontal layers;
and as it is impossible, at least with regard to the
greater number, that they were originally formed
horizontally, it is evident that they have been lifted
up; that they have been so before the others were
deposited on them.(1)
Thus the sea, previously to the formation of
horizontal layers, had formed others which certain
causes had broken up, formed again, again destroyed in
a thousand ways; and, as many of these oblique banks
which it had first formed, are loftier than those
horizontal layers which have succeeded them, and
which environ them, the causes which have given this
obliquity to these banks have also forced them above
the level of the sea, and formed them

(1) The idea supported by some geologists, that certain layers
have been formed in the oblique position in which we now find them,
in supposing it true with respect to some that are crystallized, as Mr.
Greenhough says, in the same manner as a deposite incrusts the
inside of all vessels in which gypseous waters are boded; it cannot
be applied to those which contain shells or round stones which
could not remain thus suspended, awaiting the formation of the
cement which was necessary to conglomerate them.

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ON THE REVOLUTIONS OF

into islands, or at least into rocks and inequalities,
whether elevated at one end, or that the sinking of the
other end had thrown off the waters; a second result
not less clear, nor less apparent than the former to any
one who will give himself the trouble to study the
monuments which authenticate this fact.

PROOFS THAT THESE REVOLUTIONS HAVE BEEN
NUMEROUS.

But the revolutions and changes which have left the
earth as we now find it, are not confined to the
overthrow of the ancient layers, to this retreat of the
sea after the formation of new layers.
When we compare in detail the various layers one
with another, and the productions of nature which they
comprise, we soon discover that this ancient sea has
not always deposited stones exactly similar, nor the
remains of animals of the same species, and that each
of its deposites has not extended over the whole
surface that it has covered. There have been successive
variations there established, the first of which has been
in a great measure general, and the others appear to be
less, so. The more ancient the layers are, the greater
their uniformity and extent; the more recent, the more
limited and more subject are they to vary at short
distances. Thus the displacing of the layers was
accompanied and followed by alterations in the nature
of the liquid and the materials which it held in
solution: and when certain layers, raising themselves
above the waters, had divided the surface of the sea
into islands by projecting chains, there must have been
various changes in many particular basins.

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THE SURFACE OF THE GLOBE

We must perceive that in the midst of such changes
in the nature of the liquid, the animals which it
nourished could not remain the same. The species,
their very genus, changed with the layers; and,
although at short intervals we may meet with a
recurrence of similar species, it is correct to say, in a
general sense, that the shells of the ancient layers have
their peculiar shapes, which are gradually lost, and not
found again in recent layers, still less in the sea itself,
where we never detect analagous species, nor are many
of the species itself found; that the shells of recent
layers, on the contrary, resemble in genus those still to
be found in our seas, and that in the most recent and
most shifting of these layers, and in certain lakes and
more limited deposites, there are some species which
the most practised eye cannot distinguish from those to
be found on neighbouring coasts.
There has been in animal nature a succession of
changes which has been occasioned by those of the
liquid in which the animals lived, or which at least
have had relation to them, and these variations have
gradually brought the classes of aquatic animals to
their present state: in fact, when the sea finally quitted
the continent, its inhabitants differed but very little
from those which it now produces.
We say, finally quitted,because if we scrutinize
with the most exact care these relics of organic beings,
and discover amidst marine layers, even the most
ancient, layers composed of animal or vegetable
productions of the earth and soft water; and amongst
the most recent layers, that is the most superficial, we
shell find those in which terrestrial animals are buried
beneath masses of marine productions. Thus the
various catastrophes which have shaken the layers have
not only produced by

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ON THE REVOLUTIONS OF

degrees from the bosom of the waters the different
portions of our continents, and lessened the basin of
the sea; but the basin has been displaced in many ways.
It has often happened that lands left dry by the retiring
of the waters have been again overflowed by that
element, whether they have been cast down, or the
waters have only flowed over them; and as to the soil
left dry by the sea at its last retreat, which man and
terrestrial animals now inhabit, it had been already left
dry once before, and then nourished quadrupeds, birds,
plants, and every kind of terrestrial productions; the
sea which has left it had formerly covered it. The
changes in the height of the waters have not arisen
solely from a retiring, more or less gradual or general;
it has proceeded from divers overfiowings and divers
retirings, the final result of which has been a universal
sinking of the level.

PROOFS THAT THE REVOLUTIONS HAVE BEEN
SUDDEN.

But, it is of great importance to note that these
repeated irruptions and retreats have not all been
gradual, not all uniform; on the contrary, the greater
portion of these catastrophes have been sudden; and
that is easily proved by the last of these events, that
which by a twofold action inundated, and then left dry,
our present continent, or at least a great portion of the
soil which now composes them. It also left, in the
northern countries, carcasses of large quadrupeds
frozen in the ice, and which have been preserved down
to the present period with their skin, their hair and
their flesh. If they had not