LAMARCK'S WORK IN GEOLOGY
Whatever may be said of his chemical and physical lucubrations, Lamarck
in his geological and palæontological writings is, despite their errors,
always suggestive, and in some most important respects in advance of his
time. And this largely for the reason that he had once travelled, and to
some extent observed geological phenomena, in the central regions of
France, in Germany, and Hungary; visiting mines and collecting ores and
minerals, besides being in a degree familiar with the French cretaceous
fossils, but more especially those of the tertiary strata of Paris and
its vicinity. He had, therefore, from his own experience, slight as it
was, some solid grounds of facts and observations on which to meditate
and from which to reason.
He did not attempt to touch upon cosmological theories--chaos and
creation--but, rather, confined himself to the earth, and more
particularly to the action of the ocean, and to the changes which he
believed to be due to organic agencies. The most impressive truth in
geology is the conception of the immensity of past time, and this truth
Lamarck fully realized. His views are to be found in a little book of
268 pages, entitled _Hydrogéologie_. It appeared in 1802 (an X.), or
ten years before the first publication of Cuvier's famous _Discours sur
les Revolutions de la Surface du Globe_ (1812). Written in his popular
and attractive style, and thoroughly in accord with the cosmological and
theological prepossessions of the age, the Discours was widely read, and
passed through many editions. On the other hand, the _Hydrogéologie_
died stillborn, with scarcely a friend or a reader, never reaching a
second edition, and is now, like most of his works, a bibliographical
rarity.
The only writer who has said a word in its favor, or contrasted it with
the work of Cuvier, is the judicious and candid Huxley, who, though by
no means favorable to Lamarck's factors of evolution, frankly said:
"The vast authority of Cuvier was employed in support of the
traditionally respectable hypotheses of special creation and of
catastrophism; and the wild speculations of the _Discours sur les
Revolutions de la Surface du Globe_ were held to be models of sound
scientific thinking, while the really much more sober and
philosophic hypotheses of the _Hydrogéologie_ were scouted."[60]
Before summarizing the contents of this book, let us glance at the
geological atmosphere--thin and tenuous as it was then--in which Lamarck
lived. The credit of being the first observer, before Steno (1669), to
state that fossils are the remains of animals which were once alive, is
due to an Italian, Frascatero, of Verona, who wrote in 1517.
"But," says Lyell,[61] "the clear and philosophical views of
Frascatero were disregarded, and the talent and argumentative powers
of the learned were doomed for three centuries to be wasted in the
discussion of these two simple and preliminary questions: First,
whether fossil remains had ever belonged to living creatures; and,
secondly, whether, if this be admitted, all the phenomena could not
be explained by the deluge of Noah."
Previous to this the great artist, architect, engineer, and musician,
Leonardo da Vinci (1452-1519), who, among other great works, planned and
executed some navigable canals in Northern Italy, and who was an
observer of rare penetration and judgment, saw how fossil shells were
formed, saying that the mud of rivers had covered and penetrated into
the interior of fossil shells at a time when these were still at the
bottom of the sea near the coast.[62]
That versatile and observing genius, Bernard Palissy, as early as 1580,
in a book entitled _The Origin of Springs from Rain-water_, and in other
writings, criticized the notions of the time, especially of Italian
writers, that petrified shells had all been left by the universal
deluge.
"It has happened," said Fontenelle, in his eulogy on Palissy,
delivered before the French Academy a century and a half later,
"that a potter who knew neither Latin nor Greek dared, toward the
end of the sixteenth century, to say in Paris, and in the presence
of all the doctors, that fossil shells were veritable shells
deposited at some time by the sea in the places where they were
then found; that the animals had given to the figured stones all
their different shapes, and that he boldly defied all the school of
Aristotle to attack his proofs."[63]
Then succeeded, at the end of the seventeenth century, the forerunners
of modern geology: Steno (1669), Leibnitz (1683), Ray (1692), Woodward
(1695), Vallisneri (1721), while Moro published his views in 1745. In
the eighteenth century Réaumur[64] (1720) presented a paper on the
fossil shells of Touraine.
Cuvier[65] thus pays his respects, in at least an unsympathetic way, to
the geological essayists and compilers of the seventeenth century:
"The end of the seventeenth century lived to see the birth of a new
science, which took, in its infancy, the high-sounding name of
'Theory of the Earth.' Starting from a small number of facts, badly
observed, connecting them by fantastic suppositions, it pretended to
go back to the origin of worlds, to, as it were, play with them, and
to create their history. Its arbitrary methods, its pompous
language, altogether seemed to render it foreign to the other
sciences, and, indeed, the professional savants for a long time cast
it out of the circle of their studies."
Their views, often premature, composed of half-truths, were mingled with
glaring errors and fantastic misconceptions, but were none the less
germinal. Leibnitz was the first to propose the nebular hypothesis,
which was more fully elaborated by Kant and Laplace. Buffon, influenced
by the writing of Leibnitz, in his _Théorie de la Terre_, published in
1749, adopted his notion of an original volcanic nucleus and a universal
ocean, the latter as he thought leaving the land dry by draining into
subterranean caverns. He also dimly saw, or gathered from his reading,
that the mountains and valleys were due to secondary causes; that
fossiliferous strata had been deposited by ocean currents, and that
rivers had transported materials from the highlands to the lowlands. He
also states that many of the fossil shells which occur in Europe do not
live in the adjacent seas, and that there are remains of fishes and of
plants not now living in Europe, and which are either extinct or live in
more southern climates, and others in tropical seas. Also that the bones
and teeth of elephants and of the rhinoceros and hippopotamus found in
Siberia and elsewhere in northern Europe and Asia indicate that these
animals must have lived there, though at present restricted to the
tropics. In his last essay, _Époques de la Nature_ (1778), he claims
that the earth's history may be divided into epochs, from the earliest
to the present time. The first epoch was that of fluidity, of
incandescence, when the earth and the planets assumed their form; the
second, of cooling; the third, when the waters covered the earth, and
volcanoes began to be active; the fourth, that of the retreat of the
seas, and the fifth the age when the elephants, the hippopotamus, and
other southern animals lived in the regions of the north; the sixth,
when the two continents, America and the old world, became separate; the
seventh and last being the age of man. Above all, by his attractive
style and bold suggestions he popularized the subjects and created an
interest in these matters and a spirit of inquiry which spread
throughout France and the rest of Europe.
But notwithstanding the crude and uncritical nature of the writings of
the second half of the eighteenth century, resulting from the lack of
that more careful and detailed observation which characterizes our day,
there was during this period a widespread interest in physical and
natural science, and it led up to that more exact study of nature which
signalizes the nineteenth century. "More new truths concerning the
external world," says Buckle, "were discovered in France during the
latter half of the eighteenth century than during all preceding periods
put together."[66] As Perkins[67] says: "Interest in scientific study,
as in political investigation, seemed to rise suddenly from almost
complete inactivity to extraordinary development. In both departments
English thinkers had led the way, but if the impulse to such
investigations came from without, the work done in France in every
branch of scientific research during the eighteenth century was excelled
by no other nation, and England alone could assert any claim to results
of equal importance. The researches of Coulomb in electricity, of Buffon
in geology, of Lavoisier in chemistry, of Daubenton in comparative
anatomy, carried still farther by their illustrious successors towards
the close of the century, did much to establish conceptions of the
universe and its laws upon a scientific basis." And not only did
Rousseau make botany fashionable, but Goldsmith wrote from Paris in
1755: "I have seen as bright a circle of beauty at the chemical lectures
of Rouelle as gracing the court of Versailles." Petit lectured on
astronomy to crowded houses, and among his listeners were gentlemen and
ladies of fashion, as well as professional students.[68] The
popularizers of science during this period were Voltaire, Montesquieu,
Alembert, Diderot, and other encyclopædists.
Here should be mentioned one of Buffon's contemporaries and countrymen;
one who was the first true field geologist, an observer rather than a
compiler or theorist. This was Jean E. Guettard (1715-1786). He
published, says Sir Archibald Geikie, in his valuable work, _The
Founders of Geology_, about two hundred papers on a wide range of
scientific subjects, besides half a dozen quarto volumes of his
observations, together with many excellent plates. Geikie also states
that he is undoubtedly entitled to rank among the first great pioneers
of modern geology. He was the first (1751) to make a geological map of
northern France, and roughly traced the limits of his three bands or
formations from France across the southeastern English counties. In his
work on "The degradation of mountains effected in our time by heavy
rains, rivers, and the sea,"[69] he states that the sea is the most
potent destroyer of the land, and that the material thus removed is
deposited either on the land or along the shores of the sea. He thought
that the levels of the valleys are at present being raised, owing to the
deposit of detritus in them. He points out that the deposits laid down
by the ocean do not extend far out to sea, "that consequently the
elevations of new mountains in the sea, by the deposition of sediment,
is a process very difficult to conceive; that the transport of the
sediment as far as the equator is not less improbable; and that still
more difficult to accept is the suggestion that the sediment from our
continent is carried into the seas of the New World. In short, we are
still very little advanced towards the theory of the earth as it now
exists." Guettard was the first to discover the volcanoes of Auvergne,
but he was "hopelessly wrong" in regard to the origin of basalt,
forestalling Werner in his mistakes as to its aqueous origin. He was
thus the first Neptunist, while, as Geikie states, his "observations in
Auvergne practically started the Vulcanist camp."
We now come to Lamarck's own time. He must have been familiar with the
results of Pallas's travels in Russia and Siberia (1793-94). The
distinguished German zoölogist and geologist, besides working out the
geology of the Ural Mountains, showed, in 1777, that there was a general
law in the formation of all mountain chains composed chiefly of primary
rocks;[70] the granitic axis being flanked by schists, and these by
fossiliferous strata. From his observations made on the Volga and about
its mouth, he presented proofs of the former extension, in comparatively
recent times, of the Caspian Sea. But still more pregnant and remarkable
was his discovery of an entire rhinoceros, with its flesh and skin, in
the frozen soil of Siberia. His memoir on this animal places him among
the forerunners of, if not within the ranks of, the founders of
palæontology.
Meanwhile Soldani, an Italian, had, in 1780, shown that the limestone
strata of Italy had accumulated in a deep sea, at least far from land,
and he was the first to observe the alternation of marine and
fresh-water strata in the Paris basin.
Lamarck must have taken much interest in the famous controversy between
the Vulcanists and Neptunists. He visited Freyburg in 1771; whether he
met Werner is not known, as Werner began to lecture in 1775. He must
have personally known Faujas of Paris, who, in 1779, published his
description of the volcanoes of Vivarais and Velay; while Desmarest's
(1725-1815) elaborate work on the volcanoes of Auvergne, published in
1774, in which he proved the igneous origin of basalt, was the best
piece of geological exploration which had yet been accomplished, and is
still a classic.[71]
Werner (1750-1817), the propounder of the Neptunian theory, was one of
the founders of modern geology and of palæontology. His work entitled
_Ueber die aüssern Kennzeichen der Fossilien_ appeared in 1774; his
_Kurze Klassifikation und Beschreibung der Gebirgsarten_ in 1787. He
discovered the law of the superposition of stratified rocks, though he
wrongly considered volcanic rocks, such as basalt, to be of aqueous
origin, being as he supposed formed of chemical precipitates from water.
But he was the first to state that the age of different formations can
be told by their fossils, certain species being confined to particular
beds, while others ranged throughout whole formations, and others seemed
to occur in several different formations; "the original species found in
these formations appearing to have been so constituted as to live
through a variety of changes which had destroyed hundreds of other
species which we find confined to particular beds."[72] His views as
regards fossils, as Jameson states, were probably not known to Cuvier,
and it is more than doubtful whether Lamarck knew of them. He observed
that fossils appear first in "transition" or palæozoic strata, and were
mainly corals and molluscs; that in the older carboniferous rocks the
fossils are of higher types, such as fish and amphibious animals; while
in the tertiary or alluvial strata occur the remains of birds and
quadrupeds. He thought that marine plants were more ancient than land
plants. His studies led him to infer that the fossils contained in the
oldest rocks are very different from any of the species of the present
time; that the newer the formation, the more do the remains approach in
form to the organic beings of the present creation, and that in the
very latest formations, fossil remains of species now existing occur.
Such advanced views as these would seem to entitle Werner to rank as one
of the founders of palæontology.[73]
Hutton's _Theory of the Earth_ appeared in 1785, and in a more developed
state, as a separate work, in 1795.[74] "The ruins of an older world,"
he said, "are visible in the present structure of our planet, and the
strata which now compose our continents have been once beneath the sea,
and were formed out of the waste of preëxisting continents. The same
forces are still destroying, by chemical decomposition or mechanical
violence, even the hardest rocks, and transporting the materials to the
sea, where they are spread out and form strata analogous to those of
more ancient date. Although loosely deposited along the bottom of the
ocean, they became afterwards altered and consolidated by volcanic heat,
and were then heaved up, fractured, and contorted." Again he said: "In
the economy of the world I can find no traces of a beginning, no
prospect of an end." As Lyell remarks: "Hutton imagined that the
continents were first gradually destroyed by aqueous degradation, and
when their ruins had furnished materials for new continents, they were
upheaved by violent convulsions. He therefore required alternate periods
of general disturbance and repose."
To Hutton, therefore, we are indebted for the idea of the immensity of
the duration of time. He was the forerunner of Lyell and of the
uniformitarian school of geologists.
Hutton observed that fossils characterized certain strata, but the value
of fossils as time-marks and the principle of the superposition of
stratified fossiliferous rocks were still more clearly established by
William Smith, an English surveyor, in 1790. Meanwhile the Abbé Haüy,
the founder of crystallography, was in 1802 Professor of Mineralogy in
the Jardin des Plantes.
_Lamarck's Contributions to Physical Geology; his Theory of the Earth._
Such were the amount and kind of knowledge regarding the origin and
structure of our earth which existed at the close of the eighteenth
century, while Lamarck was meditating his _Hydrogéologie_, and had begun
to study the invertebrate fossils of the Paris tertiary basin.
His object, he says in his work, is to present certain considerations
which he believed to be new and of the first order, which had escaped
the notice of physicists, and which seemed to him should serve as the
foundations for a good theory of the earth. His theses are:
1. What are the natural consequences of the influence and the
movements of the waters on the surface of the globe?
2. Why does the sea constantly occupy a basin within the limits
which contain it, and there separate the dry parts of the surface of
the globe always projecting above it?
3. Has the ocean basin always existed where we actually see it, and
if we find proofs of the sojourn of the sea in places where it no
longer remains, by what cause was it found there, and why is it no
longer there?
4. What influence have living bodies exerted on the substances found
on the surface of the earth and which compose the crust which
invests it, and what are the general results of this influence?
Lamarck then disclaims any intentions of framing brilliant hypotheses
based on supposititious principles, but nevertheless, as we shall see,
he falls into this same error, and like others of his period makes some
preposterous hypotheses, though these are far less so than those of
Cuvier's _Discours_. He distinguishes between the action of rivers or of
fresh-water currents, torrents, storms, the melting of snow, and the
work of the ocean. The rivers wear away and bear materials from the
highlands to the lowlands, so that the plains are gradually elevated;
ravines form and become immense valleys, and their sides form elevated
crests and pass into mountain ranges.
He brings out and emphasizes the fact, now so well known, that the
erosive action of rain and rivers has formed mountains of a certain
class.
"It is then evident to me, that every mountain which is not the
result of a _volcanic irruption_ or of some local catastrophe, has
been carved out from a plain, where its mass is gradually formed,
and was a part of it; hence what in this case are the summits of
the mountains are only the remains of the former level of the plain
unless the process of washing away and other means of degradation
have not since reduced its height."
Now this will apply perfectly well to our table-lands, mesas, the
mountains of our bad-lands, even to our Catskills and to many elevations
of this nature in France and in northern Africa. But Lamarck
unfortunately does not stop here, but with the zeal of an innovator, by
no means confined to his time alone, claims that the mountain masses of
the Alps and the Andes were carved out of plains which had been raised
above the sea-level to the present heights of those mountains.
Two causes, he says, have concurred in forming these elevated plains.
"One consists in the continual accumulation of material filling the
portion of the ocean-basin from which the same seas slowly retreat;
for it does not abandon those parts of the ocean-basin which are
situated nearer and nearer to the shores that it tends to leave,
until after having filled its bottom and having gradually raised it.
It follows that the coasts which the sea is abandoning are never
made by a very deep-lying formation, however often it appears to be
such, for they are continually elevated as the result of the
perpetual balancing of the sea, which casts off from its shores all
the sediments brought down by the rivers; in such a way that the
great depths of the ocean are not near the shore from which the sea
retreats, but out in the middle of the ocean and near the opposite
shores which the sea tends to invade.
"The other cause, as we shall see, is found in the detritus of
organic bodies successively accumulated, which perpetually elevates,
although with extreme slowness, the soil of the dry portions of the
globe, and which does it all the more rapidly, as the situation of
these parts gives less play to the degradation of the surface caused
by the rivers.
"Doubtless a plain which is destined some day to furnish the
mountains which the rivers will carve out from its mass would have,
when still but a little way from the sea, but a moderate elevation
above its river channels; but gradually as the ocean basin removed
from this plain, this basin constantly sinking down into the
interior (_épaisseur_) of the external crust of the globe, and the
soil of the plain perpetually rising higher from the deposition of
the detritus of organic bodies, it results that, after ages of
elevation of the plain in question, it would be in the end
sufficiently thick for high mountains to be shaped and carved out of
its mass.
"Although the ephemeral length of life of man prevents his
appreciation of this fact, it is certain that the soil of a plain
unceasingly acquires a real increase in its elevation in proportion
as it is covered with different plants and animals. Indeed the
débris successively heaped up for numerous generations of all these
beings which have by turns perished, and which, as the result of the
action of their organs, have, during the course of this life, given
rise to combinations which would never have existed without this
means, most of the principles which have formed them not being
borrowed from the soil; this débris, I say, wasting successively on
the soil of the plain in question, gradually increases the thickness
of its external bed, multiplies there the mineral matters of all
kinds and gradually elevates the formation."
Our author, as is evident, had no conception, nor had any one else at
the time he wrote, of the slow secular elevation of a continental
plateau by crust-movements, and Lamarck's idea of the formation of
elevated plains on land by the accumulation of débris of organisms is
manifestly inadequate, our aërial or eolian rocks and loess being
wind-deposits of sand and silt rather than matters of organic origin.
Thus he cites as an example of his theory the vast elevated plains of
Tartary, which he thought had been dry land from time immemorable,
though we now know that the rise took place in the quaternary or present
period. On the other hand, given these vast elevated plains, he was
correct in affirming that rivers flowing through them wore out enormous
valleys and carved out high mountains, left standing by atmospheric
erosion, for examples of such are to be seen in the valley of the Nile,
the Colorado, the Upper Missouri, etc.
He then distinguishes between granitic or crystalline mountains, and
those composed of stratified rocks and volcanic mountains.
The erosive action of rivers is thus discussed; they tend first, he
says, to fill up the ocean basins, and second, to make the surface of
the land broken and mountainous, by excavating and furrowing the plains.
Our author did not at all understand the causes of the inclination or
tilting up of strata. Little close observation or field work had yet
been done, and the rocks about Paris are but slightly if at all
disturbed. He attributes the dipping down of strata to the inclination
of the shores of the sea, though he adds that nevertheless it is often
due to local subsidences. And then he remarks that "indeed in many
mountains, and especially in the Pyrenees, in the very centre of these
mountains, we observe that the strata are for the most part either
vertical or so inclined that they more or less approach this direction."
"But," he asks, "should we conclude from this that there has
necessarily occurred a universal catastrophe, a general overturning?
This assumption, so convenient for those naturalists who would
explain all the facts of this kind without taking the trouble to
observe and study the course which nature follows, is not at all
necessary here; for it is easy to conceive that the inclined
direction of the beds in the mountains may have been produced by
other causes, and especially by causes more natural and less
hypothetical than a general overturning of strata."
While streams of fresh water tend to fill up and destroy the ocean
basins, he also insists that the movements of the sea, such as the
tides, currents, storms, submarine volcanoes, etc., on the contrary,
tend to unceasingly excavate and reëstablish these basins. Of course we
now know that tides and currents have no effect in the ocean depths,
though their scouring effects near shore in shallow waters have locally
had a marked effect in changing the relations of land and sea. Lamarck
went so far as to insist that the ocean basin owes its existence and its
preservation to the scouring action of the tides and currents.
The earth's interior was, in Lamarck's opinion, solid, formed of
quartzose and silicious rocks, and its centre of gravity did not
coincide with its geographical centre, or what he calls the _centre de
forme_. He imagined also that the ocean revolved around the globe from
east to west, and that this movement, by its continuity, displaced the
ocean basin and made it pass successively over all the surface of the
earth.
Then, in the third chapter, he asks if the basin of the sea has always
been where we now actually see it, and whether we find proofs of the
sojourn of the sea in the place where it is now absent; if so, what are
the causes of these changes. He reiterates his strange idea of a general
movement of the ocean from east to west, at the rate of at least three
leagues in twenty-four hours and due to the moon's influence. And here
Lamarck, in spite of his uniformitarian principles, is strongly
cataclysmic. What he seems to have in mind is the great equatorial
current between Africa and the West Indies. To this perpetual movement
of the waters of the Atlantic Ocean he ventures to attribute the
excavation of the Gulf of Mexico, and presumes that at the end of ages
it will break through the Isthmus of Panama, and transform America into
two great islands or two small continents. Not understanding that the
islands are either the result of upheaval, or outliers of continents,
due to subsidence, Lamarck supposed that his westward flow of the ocean,
due to the moon's attraction, eroded the eastern shores of America, and
the currents thus formed "in their efforts to move westward, arrested by
America and by the eastern coasts of China, were in great part diverted
towards the South Pole, and seeking to break through a passage across
the ancient continent have, a long time since, reduced the portion of
this continent which united New Holland to Asia into an archipelago
which comprises the Molucca, Philippine, and Mariana Islands." The West
Indies and Windward Islands were formed by the same means, and the sea
not breaking through the Isthmus of Panama was turned southward, and the
action of its currents resulted in detaching the island of Tierra del
Fuego from South America. In like manner New Zealand was separated from
New Holland, Madagascar from Africa, and Ceylon from India.
He then refers to other "displacements of the ocean basin," to the
shallowing of the Straits of Sunda, of the Baltic Sea, the ancient
subsidence of the coast of Holland and Zealand, and states that Sweden
offers all the appearance of having recently emerged from the sea, while
the Caspian Sea, formerly much larger than at present, was once in
communication with the Black Sea, and that some day the Straits of Sunda
and the Straits of Dover will be dry land, so that the union of England
and France will be formed anew.
Strangely enough, with these facts known to him, Lamarck did not see
that such changes were due to changes of level of the land rather than
to their being abandoned or invaded by the sea, but explained these by
his bizarre hypothesis of westward-flowing currents due to the moon's
action; though it should be in all fairness stated that down to recent
times there have been those who believed that it is the sea and not the
land which has changed its level.
This idea, that the sea and not the land has changed its level, was
generally held at the time Lamarck wrote, though Strabo had made the
shrewd observation that it was the land which moved. The Greek
geographer threw aside the notion of some of his contemporaries, and
with wonderful prevision, considering the time he wrote and the limited
observations he could make, claimed that it is not the sea which has
risen or fallen, but the land itself which is sometimes raised up and
sometimes depressed, while the sea-bottom may also be elevated or sunk
down. He refers to such facts as deluges, earthquakes, and volcanic
eruptions, and sudden swellings of the land beneath the sea.
"And it is not merely the small, but the large islands also, not
merely the islands, but the continents which can be lifted up
together with the sea; and, too, the large and small tracts may
subside, for habitations and cities, like Bure, Bizona, and many
others, have been engulfed by earthquakes."[75]
But it was not until eighteen centuries later that this doctrine, under
the teachings of Playfair, Leopold von Buch, and Élie de Beaumont
(1829-30) became generally accepted. In 1845 Humboldt remarked, "It is a
fact to-day recognized by all geologists, that the rise of continents is
due to an actual upheaval, and not to an apparent subsidence occasioned
by a general depression of the level of the sea" (_Cosmos_, i). Yet as
late as 1869 we have an essay by H. Trautschold[76] in which is a
statement of the arguments which can be brought forward in favor of the
doctrine that the increase of the land above sea level is due to the
retirement of the sea.[77]
As authentic and unimpeachable proofs of the former existence of the sea
where now it is absent, Lamarck cites the occurrence of fossils in rocks
inland. Lamarck's first paper on fossils was read to the Institute in
1799, or about three years previous to the publication of the
_Hydrogéologie_. He restricts the term "fossils" to vegetable and animal
remains, since the word in his time was by some loosely applied to
minerals as well as fossils; to anything dug out of the earth. "We find
fossils," he says, "on dry land, even in the middle of continents and
large islands; and not only in places far removed from the sea, but even
on mountains and in their bowels, at considerable heights, each part of
the earth's surface having at some time been a veritable ocean bottom."
He then quotes at length accounts of such instances from Buffon, and
notices their prodigious number, and that while the greater number are
marine, others are fresh-water and terrestrial shells, and the marine
shells may be divided into littoral and pelagic.
"This distinction is very important to make, because the
consideration of fossils is, as we have already said, one of the
principal means of knowing well the revolutions which have taken
place on the surface of our globe. This subject is of great
importance, and under this point of view it should lead naturalists
to study fossil shells, in order to compare them with their
analogues which we can discover in the sea; finally, to carefully
seek the places where each species lives, the banks which are
formed of them, the different beds which these banks may present,
etc., etc., so that we do not believe it out of place to insert here
the principal considerations which have already resulted from that
which is known in this respect.
"_The fossils which are found in the dry parts of the surface of the
globe are evident indications of a long sojourn of the sea in the very
places where we observe them._" Under this heading, after repeating the
statement previously made that fossils occur in all parts of the dry
land, in the midst of the continents and on high mountains, he inquires
_by what cause_ so many marine shells could be found in the explored
parts of the world. Discarding the old idea that they are monuments of
the deluge, transformed into fossils, he denies that there was such a
general catastrophe as a universal deluge, and goes on to say in his
assured, but calm and philosophic way:
"On the globe which we inhabit, everything is submitted to continual
and inevitable changes, which result from the essential order of
things: they take place, in truth, with more or less promptitude or
slowness, according to the nature, the condition, or the situation
of the objects; nevertheless they are wrought in some time or other.
"To nature, time is nothing, and it never presents a difficulty; she
always has it at her disposal, and it is for her a means without
limit, with which she has made the greatest as well as the least
things.
"The changes to which everything in this world is subjected are
changes not only of form and of nature, but they are changes also of
bulk, and even of situation.
"All the considerations stated in the preceding chapters should
convince us that nothing on the surface of the terrestrial globe is
immutable. They teach us that the vast ocean which occupies so great
a part of the surface of our globe cannot have its bed constantly
fixed in the same place; that the dry or exposed parts of this
surface themselves undergo perpetual changes in their condition, and
that they are in turn successively invaded and abandoned by the sea.
"There is, indeed, every evidence that these enormous masses of
water continually displace themselves, both their bed and their
limits.
"In truth these displacements, which are never interrupted, are in
general only made with extreme and almost inappreciable slowness,
but they are in ceaseless operation, and with such constancy that
the ocean bottom, which necessarily loses on one side while it gains
on another, has already, without doubt, spread over not only once,
but even several times, every point of the surface of the globe.
"If it is thus, if each point of the surface of the terrestrial
globe has been in turn dominated by the seas--that is to say, has
contributed to form the bed of those immense masses of water which
constitute the ocean--it should result (1) that the insensible but
uninterrupted transfer of the bed of the ocean over the whole
surface of the globe has given place to deposits of the remains of
marine animals which we should find in a fossil state; (2) that this
translation of the ocean basin should be the reason why the dry
portions of the earth are always more elevated than the level of the
sea; so that the old ocean bed should become exposed without being
elevated above the sea, and without consequently giving rise to the
formation of mountains which we observe in so many different regions
of the naked parts of our globe."
Thus littoral shells of many genera, such as Pectens, Tellinæ, cockle
shells, turban shells (_sabots_), etc., madrepores and other littoral
polyps, the bones of marine or of amphibious animals which have lived
near the sea, and which occur as fossils, are then unimpeachable
monuments of the sojourn of the sea on the points of the dry parts of
the globe where we observe their deposits, and besides these occur
deep-water forms. "Thus the encrinites, the belemnites, the
orthoceratites, the ostracites, the terebratules, etc., all animals
which habitually live at the bottom, found for the most part among the
fossils deposited on the point of the globe in question, are
unimpeachable witnesses which attest that this same place was once part
of the bottom or great depths of the sea." He then attempts to prove,
and does so satisfactorily, that the shells he refers to are what he
calls deep-water (pélagiennes). He proves the truth of his thesis by the
following facts:
1. We are already familiar with a marine Gryphæa, and different
Terebratulæ, also marine shell-fish, which do not, however, live
near shore. 2. Also the greatest depth which has been reached with
the rake or the dredge is not destitute of molluscs, since we find
there a great number which only live at this depth, and without
instruments to reach and bring them up we should know nothing of the
_cones_, _olives_, Mitra, many species of Murex, Strombus, etc. 3.
Finally, since the discovery of a living Encrinus, drawn up on a
sounding line from a great depth, and where lives the animal or
polyp in question, it is not only possible to assure ourselves that
at this depth there are other living animals, but on the contrary we
are strongly bound to think that other species of the same genus,
and probably other animals of different genera, also live at the
same depths. All this leads one to admit, with Bruguière,[78] the
existence of deep-water shell-fish and polyps, which, like him, I
distinguish from littoral shells and polyps.
"The two sorts of monuments of which I have above spoken, namely,
littoral and deep-sea fossils, may be, and often should be, found
separated by different beds in the same bank or in the same
mountains, since they have been deposited there at very different
epochs. But they may often be found mixed together, because the
movements of the water, the currents, submarine volcanoes, etc.,
have overturned the beds, yet some regular deposits in water always
tranquil would be left in quite distant beds.... Every dry part of
the earth's surface, when the presence or the abundance of marine
fossils prove that formerly the sea has remained in that place, has
necessarily twice received, for a single incursion of the sea,
littoral shells, and once deep-sea shells, in three different
deposits--this will not be disputed. But as such an incursion of the
sea can only be accomplished by a period of immense duration, it
follows that the littoral shells deposited at the first sojourn of
the edge of the sea, and constituting the first deposit, have been
destroyed--that is to say, have not been preserved to the present
time; while the deep-water shells form the second deposit, and there
the littoral shells of the third deposit are, in fact, the only ones
which now exist, and which constitute the fossils that we see."
He again asserts that these deposits could not be the result of any
sudden catastrophe, because of the necessarily long sojourn of the sea
to account for the extensive beds of fossil shells, the remains of
"infinitely multiplied generations of shelled animals which have lived
in this place, and have there successively deposited their débris." He
therefore supposes that these remains, "continually heaped up, have
formed these shell banks, become fossilized after the lapse of
considerable time, and in which it is often possible to distinguish
different beds." He then continues his line of anti-catastrophic
reasoning, and we must remember that in his time facts in biology and
geology were feebly grasped, and scientific reasoning or induction was
in its infancy.
"I would again inquire how, in the supposition of a universal
catastrophe, there could have been preserved an infinity of delicate
shells which the least shock would break, but of which we now find a
great number uninjured among other fossils. How also could it happen
that bivalve shells, with which calcareous rocks and even those
changed into a silicious condition are interlarded, should be all
still provided with their two valves, as I have stated, if the
animals of these shells had not lived in these places?
"There is no doubt but that the remains of so many molluscs, that so
many shells deposited and consequently changed into fossils, and
most of which were totally destroyed before their substance became
silicified, furnished a great part of the calcareous matter which we
observe on the surface and in the upper beds of the earth.
"Nevertheless there is in the sea, for the formation of calcareous
matter, a cause which is greater than shelled molluscs, which is
consequently still more powerful, and to which must be referred
ninety-nine hundredths, and indeed more, of the calcareous matter
occurring in nature. This cause, so important to consider, is the
existence of _coralligenous polyps_, which we might therefore call
_testaceous polyps_, because, like the testaceous molluscs, these
polyps have the faculty of forming, by a transudation or a continual
secretion of their bodies, the stony and calcareous polypidom on
which they live.
"In truth these polyps are animals so small that a single one only
forms a minute quantity of calcareous matter. But in this case what
nature does not obtain in any volume or in quantity from any one
individual, she simply receives by the number of animals in
question, through the enormous multiplicity of these animals, and
their astonishing fecundity--namely, by the wonderful faculty they
have of promptly regenerating, of multiplying in a short time their
generations successively, and rapidly accumulating; finally, by the
total amount of reunion of the products of these numerous little
animals.
"Moreover, it is a fact now well known and well established that the
coralligenous polyps, namely, this great family of animals with
coral stocks, such as the millepores, the madrepores, astrææ,
meandrinæ, etc., prepare on a great scale at the bottom of the sea,
by a continual secretion of their bodies, and as the result of their
enormous multiplication and their accumulated generations, the
greatest part of the calcareous matter which exists. The numerous
coral stocks which these animals produce, and whose bulk and numbers
perpetually increase, form in certain places islands of considerable
extent, fill up extensive bays, gulfs, and roadsteads; in a word,
close harbors, and entirely change the condition of coasts.
"These enormous banks of madrepores and millepores, heaped upon each
other, covered and intermingled with serpulæ, different kinds of
oysters, patellæ, barnacles, and other shells fixed by their base,
form irregular mountains of an almost limitless extent.
"But when, after the lapse of considerable time, the sea has left
the places where these immense deposits are laid down, then the slow
but combined alteration that these great masses undergo, left
uncovered and exposed to the incessant action of the air, light, and
a variable humidity, changes them gradually into fossils and
destroys their membranous or gelatinous part, which is the readiest
to decompose. This alteration, which the enormous masses of the
corals in question continued to undergo, caused their structure to
gradually disappear, and their great porosity unceasingly diminished
the parts of these stony masses by displacing and again bringing
together the molecules composing them, so that, undergoing a new
aggregation, these calcareous molecules obtained a number of points
of contact, and constituted harder and more compact masses. It
finally results that instead of the original masses of madrepores
and millepores there occurs only masses of a compact calcareous
rock, which modern mineralogists have improperly called _primitive
limestone_, because, seeing in it no traces of shells or corals,
they have mistaken these stony masses for deposits of a matter
primitively existing in nature."
He then reiterates the view that these deposits of marble and
limestones, often forming mountain ranges, could not have been the
result of a universal catastrophe, and in a very modern way goes on to
specify what the limits of catastrophism are. The only catastrophes
which a naturalist can reasonably admit as having taken place are
partial or local ones, those dependent on causes acting in isolated
places, such as the disturbances which are caused by volcanic eruptions,
by earthquakes, by local inundations, by violent storms, etc. These
catastrophes are with reason admissible, because we observe their
analogues, and because we know that they often happen. He then gives
examples of localities along the coast of France, as at Manche, where
there are ranges of high hills made up of limestones containing Gryphææ,
ammonites, and other deep-water shells.
In the conclusion of the chapter, after stating that the ocean has
repeatedly covered the greater part of the earth, he then claims that
"the displacement of the sea, producing a constantly variable
inequality in the mass of the terrestrial radii, has necessarily caused
the earth's centre of gravity to vary, as also its two poles.[79]
Moreover, since it appears that this variation, very irregular as it is,
not being subjected to any limits, it is very probable that each point
of the surface of the planet we inhabit is really in the case of
successively finding itself subjected to different climates." He then
exclaims in eloquent, profound, and impassioned language:
"How curious it is to see that such suppositions receive their
confirmation from the consideration of the state of the earth's
surface and of its external crust, from that of the nature of
certain fossils found in abundance in the northern regions of the
earth, and whose analogues now live in warm climates; finally, in
that of the ancient astronomical observations of the Egyptians.
"Oh, how great is the antiquity of the terrestrial globe, and how
small are the ideas of those who attribute to the existence of this
globe a duration of six thousand and some hundred years since its
origin down to our time!
"The physico-naturalist and the geologist in this respect see things
very differently; for if they have given the matter the slightest
consideration--the one, the nature of fossils spread in such great
numbers in all the exposed parts of the globe, both in elevated
situations and at considerable depths in the earth; the other, the
number and disposition of the beds, as also the nature and order of
the materials which compose the external crust of this globe studied
throughout a great part of its thickness and in the mountain
masses--have they not had opportunities to convince themselves that
the antiquity of this same globe is so great that it is absolutely
beyond the power of man to appreciate it in an adequate way!
"Assuredly our chronologies do not extend back very far, and they
could only have been made by propping them up by fables. Traditions,
both oral and written, become necessarily lost, and it is in the
nature of things that this should be so.
"Even if the invention of printing had been more ancient than it is,
what would have resulted at the end of ten thousand years?
Everything changes, everything becomes modified, everything becomes
lost or destroyed. Every living language insensibly changes its
idiom; at the end of a thousand years the writings made in any
language can only be read with difficulty; after two thousand years
none of these writings will be understood. Besides wars, vandalism,
the greediness of tyrants and of those who guide religious opinions,
who always rely on the ignorance of the human race and are supported
by it, how many are the causes, as proved by history and the
sciences, of epochs after epochs of revolutions, which have more or
less completely destroyed them.
"How many are the causes by which man loses all trace of that which
has existed, and cannot believe nor even conceive of the immense
antiquity of the earth he inhabits!
"How great will yet seem this antiquity of the terrestrial globe in
the eyes of man when he shall form a just idea of the origin of
living bodies, as also of the causes of the development and of the
gradual process of perfection of the organization of these bodies,
and especially when it will be conceived that, time and favorable
circumstances having been necessary to give existence to all the
living species such as we actually see, he is himself the last
result and the actual maximum of this process of perfecting, the
limit (_terme_) of which, if it exists, cannot be known."
In the fourth chapter of the book there is less to interest the reader,
since the author mainly devotes it to a reiteration of the ideas of his
earlier works on physics and chemistry. He claims that the minerals and
rocks composing the earth's crust are all of organic origin, including
even granite. The thickness of this crust he thinks, in the absence of
positive knowledge, to be from three to four leagues, or from nine to
twelve miles.
After describing the mode of formation of minerals, including agates,
flint, geodes, etc., he discusses the process of fossilization by
molecular changes, silicious particles replacing the vegetable or animal
matter, as in the case of fossil wood.
While, then, the products of animals such as corals and molluscs are
limestones, those of vegetables are humus and clay; and all of these
deposits losing their less fixed principles pass into a silicious
condition, and end by being reduced to quartz, which is the earthy
element in its purest form. The salts, pyrites, and metals only differ
from other minerals by the different circumstances under which they were
accumulated, in their different proportions, and in their much greater
amount of carbonic or acidific fire.
Regarding granite, which, he says, naturalists very erroneously consider
as _primitive_, he begins by observing that it is only by conjecture
that we should designate as primitive any matter whatever. He recognizes
the fact that granite forms the highest mountains, which are generally
arranged in more or less regular chains. But he strangely assumes that
the constituents of granite, _i.e._, felspar, quartz, and mica, did not
exist before vegetables, and that these minerals and their aggregation
into granite were the result of slow deposition in the ocean.[80] He
goes so far as to assert that the porphyritic rocks were not thus formed
in the sea, but that they are the result of deposits carried down by
streams, especially torrents flowing down from mountains. Gneiss, he
thinks, resulted from the detritus of granitic rocks, by means of an
inappreciable cement, and formed in a way analogous to that of the
porphyries.
Then he attacks the notion of Leibnitz of a liquid globe, in which all
mineral substances were precipitated tumultuously, replacing this idea
by his chemical notion of the origin of the crystalline and volcanic
rocks.
He is on firmer ground in explaining the origin of chalk and clay, for
the rocks of the region about Paris, with which he was familiar, are
sedimentary and largely of organic origin.
In the "Addition" (pp. 173-188) following the fourth chapter Lamarck
states that, allowing for the variations in the intensity of the cause
of elevation of the land as the result of the accumulations of organic
matter, he thinks he can, without great error, consider the mean rate as
324 mm. (1 foot) a century. As a concrete example it has been observed,
he says, that one river valley has risen a foot higher in the space of
eleven years.
Passing by his speculations on the displacement of the poles of the
earth, and on the elevations of the equatorial regions, which will
dispense with the necessity of considering the earth as originally in a
liquid condition, he allows that "the terrestrial globe is not at all a
body entirely and truly solid, but that it is a combination (_réunion_)
of bodies more or less solid, displaceable in their mass or in their
separate parts, and among which there is a great number which undergo
continual changes in condition."
It was, of course, too early in the history of geology for Lamarck to
seize hold of the fact, now so well known, that the highest mountain
ranges, as the Alps, Pyrenees, the Caucasus, Atlas ranges, and the
Mountains of the Moon (he does not mention the Himalayas) are the
youngest, and that the lowest mountains, especially those in the more
northern parts of the continents, are but the roots or remains of what
were originally lofty mountain ranges. His idea, on the contrary, was,
that the high mountain chains above mentioned were the remains of
ancient equatorial elevations, which the fresh waters, for an enormous
multitude of ages, were in the process of progressively eroding and
wearing down.
What he says of the formation of coal is noteworthy:
"Wherever there are masses of fossil wood buried in the earth, the
enormous subterranean beds of coal that are met with in different
countries, these are the witnesses of ancient encroachments of the
sea, over a country covered with forests; it has overturned them,
buried them in deposits of clay, and then after a time has
withdrawn."
In the appendix he briefly rehearses the laws of evolution as stated in
his opening lecture of his course given in the year IX. (1801), and
which would be the subject of his projected work, _Biologie_, the third
and last part of the Terrestrial Physics, a work which was not
published, but which was probably comprised in his _Philosophie
zoologique_.
The _Hydrogéologie_ closes with a "_Mémoire sur la matière du feu_" and
one "_sur la matière du son_," both being reprinted from the _Journal de
Physique_.
FOOTNOTES:
[60] _Evolution in Biology_, in _Darwiniana_, New York, 1896, p. 212.
[61] _Principles of Geology_.
[62] Lyell's _Principles of Geology_, 8th edit., p. 22.
[63] Quoted from Flourens' _Éloge Historique de Georges Cuvier_,
Hoefer's edition. Paris, 1854.
[64] _Remarques sur les Coquilles fossiles de quelques Cantons de la
Touraine_. Mém. Acad. Sc. Paris, 1720, pp. 400-417.
[65] _Éloge Historique de Werner_, p. 113.
[66] _History of Civilization_, i. p. 627.
[67] _France under Louis XV._, p. 359.
[68] _France under Louis XV._, p. 360.
[69] See vol. iii. of his _Mémoires sur differentes Parties des Sciences
et des Arts_, pp. 209-403. Geikie does not give the date of the third
volume of his work, but it was apparently about 1771, as vol. ii. was
published in 1770. I copy Geikie's account of Guettard's observations
often in his own words.
[70] Lyell's _Principles of Geology_.
[71] Geikie states that the doctrine of the origin of valleys by the
erosive action of the streams which flow through them, though it has
been credited to various writers, was first clearly taught from actual
concrete examples by Desmarest. _L. c._, p. 65.
[72] Jameson's _Cuvier's Theory of the Earth_, New York, 1818.
[73] J. G. Lehmann of Berlin, in 1756, first formally stated that there
was some regular succession in the strata, his observations being based
on profiles of the Hartz and the Erzgebirge. He proposed the names
Zechstein, Kupferschiefer, rothes Todtliegendes, which still linger in
German treatises. G. C. Fuchsel (1762) wrote on the stratigraphy of the
coal measures, the Permian and the later systems in Thuringia. (Zittel.)
[74] James Hutton was born at Edinburgh, June 3, 1726, where he died
March 26, 1797.
[75] Quoted from Lyell's _Principles of Geology_, eighth edit., p. 17.
[76] _Bulletin Société Imp. des Naturalistes De Moscou_, xlii. (1869),
pt. 1. p. 4, quoted from Geikie's _Geology_, p. 276, footnote.
[77] Suess also, in his _Anlitz_ etc., substitutes for the folding of
the earth's crust by tangential pressure the subsidence by gravity of
portions of the crust, their falling in obliging the sea to follow.
Suess also explains the later transgressions of the sea by the
progressive accumulation of sediments which raise the level of the sea
by their deposition at its bottom. Thus he believes that the true factor
in the deformation of the globe is vertical descent, and not, as Neumayr
had previously thought, the folding of the crust.
[78] Bruguière (1750-1799), a conchologist of great merit. His
descriptions of new species were clear and precise. In his paper on the
coal mines of the mountains of Cevennes (Choix de Mémoires d'Hist. Nat.,
1792) he made the first careful study of the coal formation in the
Cevennes, including its beds of coal, sandstone, and shale. A. de
Jussieu had previously supposed that the immense deposits of coal were
due to sudden cataclysms or to one of the great revolutions of the earth
during which the seas of the East or West Indies, having been driven as
far as into Europe, had deposited on its soil all these exotic plants to
be found there, after having torn them up on their way.
But Bruguière, who is to be reckoned among the early uniformitarians,
says that "the capacity for observation is now too well-informed to be
contented with such a theory," and he explains the formation of coal
deposits in the following essentially modern way:
"The stores of coal, although formed of vegetable substances, owe their
origin to the sea. It is when the places where we now find them were
covered by its waters that these prodigious masses of vegetable
substances were gathered there, and this operation of nature, which
astonishes the imagination, far from depending on any extraordinary
commotion of the globe, seems, on the contrary, to be only the result of
time, of an order of things now existing, and especially that of slow
changes" (i, pp. 116, 117).
The proofs he brings forward are the horizontality of the beds, both of
coal and deposits between them, the marine shells in the sandstones, the
fossil fishes intermingled with the plant remains in the shales;
moreover, some of the coal deposits are covered by beds of limestone
containing marine shells which lived in the sea at a very great depth.
The alternation of these beds, the great mass of vegetable matter which
lived at small distances from the soil which conceals them, and the
occurrence of these beds so high up, show that at this time Europe was
almost wholly covered by the sea, the summits of the Alps and the
Pyrenees being then, as he says, so many small islands in the midst of
the ocean. He also intimates that the climate when these ferns ("bamboo"
and "banana") lived was warmer than that of Europe at present.
In this essay, then, we see a great advance in correctness of geological
observation and reasoning over any previous writers, while its
suggestions were appreciated and adopted by Lamarck.
[79] Hooke had previously, in order to explain the presence of tropical
fossil shells in England, indulged in a variety of speculations
concerning changes in the position of the axis of the earth's rotation,
"a shifting of the earth's centre of gravity analogous to the
revolutions of the magnetic pole, etc." (Lyell's _Principles_). See also
p. 132.
[80] Cuvier, in a footnote to his _Discours_ (sixth edition, p. 49), in
referring to this view, states that it originated with Rodig (_La
Physique_, p. 106, Leipzig, 1801) and De Maillet (_Telliamed_, tome ii.,
p. 169), "also an infinity of new German works." He adds: "M. de Lamarck
has recently expanded this system in France at great length in his
_Hydrogéologie_ and in his _Philosophie zoologique_." Is the Rodig
referred to Ih. Chr. Rodig, author of _Beiträge zur Naturwissenschaft_
(Leipzig, 1803. 8^o)? We have been unable to discover this view in De
Maillet; Cuvier's reference to p. 169 is certainly incorrect, as quite a
different subject is there discussed.