the tops of the highest mountains, but there are some met with in their
natural condition, and which have the gloss, colours, and lightness of
sea-shells; and to convince ourselves entirely of this matter, we have
only to compare them with those found on the sea shores. A slight
examination will prove that these fossil and petrified shells are the
same as those of the sea; they are marked with the same articulations
and in the glossopetri, and other teeth of fishes, which are sometimes
found adhering to the jaw-bone, the teeth of the fish are remarked to be
smooth and worn at the extremities, and that they have been made use of
when the animals were alive.
Almost every where on land we meet with fossil-shells, and of those of
the same kind, some are small, others large, some young, others old;
some imperfect, others extremely perfect and we likewise sometimes see
the young ones adhering to the old.
The shell-fish called _purpura_ has a long tongue, the extremity of
which is bony, and so sharp, that it pierces the shells of other fish;
by which means it draws nutriment from them. Shells pierced in this
manner are frequently found in the earth, which is an incontestible
proof that they formerly inclosed living fish, and existed in those
parts where there were the Purpura.
The obelisks of St. Peter's at Rome, according to John of Latran, were
said to come from the pyramids of Egypt; they are of red granite, which
is a kind of rock-stone, and, as we have observed, contains no shells;
but the African and Egyptian marble, and the porphyry said to have been
cut from the temple of Solomon, and the palaces of the kings of Egypt,
and used at Rome in different buildings, are filled with shells. Red
porphyry is composed of an infinite number of prickles of the species of
echinus, or sea chesnut; they are placed pretty near each other, and
form all the small white spots which are in the porphyry. Each of these
white spots has a black one in its centre, which is the section of the
longitudinal tube of the prickles of the echinus. At Fichen, three
leagues from Dijon, in Burgundy, is a red stone perfectly similar in its
composition to porphyry, and which differs from it only in hardness, not
being more so than marble; it appears almost formed of prickles of the
echini, and its beds are of a very great extent. Many beautiful pieces
of workmanship have been made of it in this province, and particularly
the steps of the pedestal of the equestrian statue of Louis le Grand, at
Dijon.
This species of stone is also found at Montbard, in Burgundy, where
there is an extensive quarry; it is not so hard as marble, contains more
of the echini, and less of the red matter. From this it appears that
the ancient porphyry of Egypt differs only from that of Burgundy in the
degree of hardness, and the number of the points of the echini.
With respect to what the curious call green porphyry, I rather suppose
it to be a granite than a porphyry; it is not composed of spots like the
red porphyry, and its substance appears to be similar to that of a
common granite. In Tuscany, in the stone with which the ancient walls of
Volatera were built, there are a great quantity of shells, and this wall
was built 2500 years ago. Most marbles, porphyries, and other stones of
the most ancient buildings, contain shells and other wrecks of marine
productions, as well as the marble we at present take from the quarry;
therefore it cannot be doubted, independent even of the sacred testimony
of holy writ, that before the deluge the earth was composed of the same
materials at it is at present.
From all these facts it is plain that petrified shells are found in
Europe, Asia, Africa, and in every place where the observations have
been made; they are also found in America, in the Brasils; for example,
in Tucumama, in Terra Magellinica, and in such a great quantity in the
Antilles, that directly below the cultivable land, the bottom of which
the inhabitants call lime, is nothing but a composition of shells,
madrepores, astroites, and other productions of the sea. These facts
would have made me think that shells and other petrified marine
productions were to be found in the greatest part of the continent of
America, and especially in the mountains, as Woodward asserts; but M.
Condamine, who lived several years at Peru, has assured me he could not
discover any in the Cordeliers, although he had carefully sought for
them. This exception would be singular, and the consequences that might
be drawn from it would be still more so; but I own that, in spite of the
testimony of this celebrated naturalist, I am much inclined to suppose,
that in the mountains of Peru, as well as elsewhere, there are shells
and other marine petrifications, although they have not been discovered.
It is well known, that in matter of testimonies, two positive witnesses,
who assert to have seen a thing, is sufficient to make a complete proof;
whereas ten thousand negative witnesses, and who can only assert not to
have seen a thing, can only raise a slight doubt. This reason, united
with the strength of analogy, induces me to persist in thinking the
shells will be found on the mountains of Peru, especially if we search
for them on the rise of the mountain, and not at the summit.
The tops of the highest mountains are generally composed of rock, stone
granite, and other vitrifiable matters, which contain no shells.
All these matters were formed out of the beds of the sand of the sea,
which covered the tops of these mountains. When the sea left them, the
sand and other light bodies were carried by the waters into the plains,
so that there remained only rocks on the tops of the mountains, which
had been formed under those beds of sand. At two, three, or four hundred
fathoms below the tops of these mountains, are often found marble and
other calcinable matter, which are disposed in parallel strata, and
contain shells and other marine productions; therefore it is not
surprising that M. de la Condamine did not find any shells on these
mountains, especially if he sought for them in the elevated parts of
those mountains which are composed of rock, free-stone, or vitrifiable
sand; but had he examined the lower parts of the Cordeliers, he would
undoubtedly have found strata of stone, marble, earth, &c. mixed with
shells; for in every country where observations have been made, such
beds have always been met with.
But suppose that in fact there are no marine productions in the
mountains of Peru, all that may be concluded from it will no ways affect
our theory; and it might be possible, that there are some parts of the
globe which never were covered with water, especially of such elevation
as the Cordeliers. But in this case there might be some curious
observations made on those mountains, for they would not be composed of
parallel strata, the materials also would be very different from those
we are acquainted with; they would not have perpendicular cracks; the
composition of the rocks and stones would not at all resemble those of
other countries; and lastly, in these mountains we should find the
ancient structure of the earth such as it originally was before it was
changed by the motion of the waters; we should see the first state of
the globe, the old matters of which it was composed, its form, and the
natural arrangement of its parts; but this is too much to expect, and on
too slight foundations; and it is more conformable to reason to conclude
that fossil-shells are to be found in those mountains, as well as in
every other place.
With respect to the manner in which shells are placed in the strata of
earth or sand, Woodward says, "All shells that are met with in an
infinity of strata of earth, and banks of rocks, in the highest
mountains, and in the deepest quarries and mines, in flints, &c. &c. in
masses of sulphur, marcasites, and other metallic and mineral bodies,
are filled with similar substances to that which includes them, and
never any heterogeneous matter, &c.
"In the sand stones of all countries (the specific weight of the
different kinds of which vary but little, being generally with respect
to water as 2-1/2 or 9/16 to 1), we find only the conchae, and other
shells which are nearly of the same weight, but they are usually found
in very great numbers, whereas it is very rare to meet with
oyster-shells (whose specific weight is but as 2-1/3 to 1), or sea
cockles (whose weight is but as 2 or 2-1/8 to 1), or other sorts of
lighter shells; but on the contrary in chalk, (which is lighter than
stone, being to water but as 2-1/10 to 1), we find only cockles and
other kinds of lighter shells, page 32, 33."
It must be remarked, that what Woodward says in this place with respect
to specific gravity, must not be looked upon as a general rule, for we
find lighter and heavier shells in the same matters; for example, shells
of cockles, of oysters, of echini, &c. are found in the same stones and
earth; and even in the royal cabinet may be seen a petrified cockle in a
cornelian, and echini petrified in an agate, &c. therefore the specific
weight of the shells has not influenced so much as Woodward supposes
their position in the earth. The reason why such light shells are found
more abundantly in chalk is, that chalk is only the ruinated part of
shells, and that those of the echini being lighter and thinner than
others, would have been most easily reduced into powder or chalk, so
that the strata of chalk are only met with in the places where formerly
a great abundance of these light shells were collected, the destruction
of which formed that chalk, in which we find those shells, which having
resisted the frictions, are preserved entire, or at least in parts large
enough to discover their species.
But this subject is treated more fully in our discourse on minerals; we
shall here content ourselves with saying, that a modification must be
given to Woodward's expressions: he seems to say, that shells are found
in flints, cornelians, in ores, and sulphur, as often, and in as great
a number as in other matters; whereas the truth is, that they are very
rare in all vitrifiable or purely inflammable substances; and, on the
contrary, are in prodigious abundance in chalk, marl, and marbles,
insomuch that we cannot absolutely pretend to say, that the lightest and
heaviest shells are found in corresponding strata, but only that in
general they are oftener found so than otherwise. They are all filled
with the substance which surrounds them, whether found in horizontal
strata or in perpendicular fissures, because both have been formed by
the waters, although at different times and in different manners. Those
found in horizontal strata of stone, marble, &c. have been deposited by
the motion of the waves of the sea, and those in flints, cornelians, and
all matters which are in the perpendicular fissures, have been produced
by the particular motion of a small quantity of water, loaded with
lapidific or metallic substances. In both cases these matters were
reduced into a fine and impalpable powder, which has filled the shells
so fully and absolutely, as not to have left the least vacuum.
There is therefore in stone, marble, &c. a great multitude of shells
which are whole, beautiful, and so little changed, that they may be
easily compared with the shells preserved in cabinets, or found on the
sea shores.
Woodward, in pages 23 and 24, proceeds, "There are, besides these, great
multitudes of shells contained in stones, &c. which are entire and
absolutely free from any such mineral mixture; which may be compared
with those at this time seen on our shores, and which will be found not
to have any difference, being precisely of the same figure and size; of
the same substance and texture as the peculiar matter which composes
them is the same, and is disposed and arranged in the same manner; the
direction of their fibres and spiral lines are the same, the composition
of the small lama formed by their fibres is the same in the one as the
other; we see in the same part vestigia of tendons, by means of which
the animal was fastened and joined to its shell; we see the same
tubercles, stria and pipes; in short, the whole is alike, whether within
or without the shell, in its cavity or on its convexity, in its
substance or on its superficies. In other respects these fossil
shell-fish are subject to the same common accidents as those of the sea;
for example, they sometimes grow to one another, the least are adherent
to the large; they have vermicular conduits; pearls are found therein,
and other similar matters which have been produced by the animal when it
inhabited its shell; and what is very considerable, their specific
gravity is exactly the same as that of their kind found actually in the
sea; in all chymical experiments they answer exactly with sea-shells;
when dissolved they have the same appearance, smell and taste; in a
word, their resemblance is perfectly exact."
I have often observed with astonishment, as I have already said, whole
mountains, chains of rocks, enormous banks of quarries, so full of
shells and other wrecks of marine productions, that their bulk surpassed
that of the matter in which they were deposited.
I have seen cultivated fields so full of petrified cockles that a man
might pick them up with his eyes shut, others covered with cornu
ammonis, and some with cardites; and the more we examine the earth, the
more we shall be convinced that the number of these petrifications is
infinite, and conclude, that it is impossible that all the animals which
inhabited these shells existed at one time.
I have made an observation, that in all countries where we find a very
great number of petrified shells in the cultivated lands which are
whole, well preserved, and totally apart, have been divided by the
action of the frost, which destroys the stone and suffers the petrified
shells to subsist a longer time.
This immense quantity of marine fossils found in so many places, proves
that they could not have been transported thither by the deluge; for if
these shells had been brought on the earth by a deluge, the greatest
part would have remained on the surface of the earth, or at least would
not have entered to the depth of seven or eight hundred feet in the most
solid marble.
In all quarries these shells form a share of the internal part of the
stone, sometimes externally covered with stalactites, which is much less
ancient matter than stone, which contains shells. Another proof this
happened not by a deluge is, that bones, horns, claws, &c. of land
animals, are found but very rarely, and not at all in marble and other
hard stone whereas if it was the effect of a deluge, where all must have
perished, we should meet with the remains of land animals as well as
those of the sea.
It is a vain supposition to pretend that all the earth was dissolved at
the deluge, nor can we give any foundation to such idea, but by
supposing a second miracle, to give the water the property of a
universal dissolvent. Besides, what annihilates the supposition, and
renders it even contradictory, is, that if all matters were dissolved by
that water, yet shells have not been so, since we find them entire and
well preserved in all the masses which are said to have been dissolved;
this evidently proves that there never was such dissolution, and that
the arrangement of the parallel strata was not made in an instant, but
by successive sediments: for it is evident to all who will take the
trouble of observing, that the arrangement of all the materials which
compose the globe, is the work of the waters. The question therefore is
only whether this arrangement was made at once, or in a length of time:
now we have shewn it could not be done all at once, because the
materials have not kept the order of specific weight, and there has not
been a general dissolution; therefore this arrangement must have been
produced by sediments deposited in succession of time; any other
revolution, motion, or cause, would have produced a very different
arrangement. Besides, particular revolutions, or accidental causes,
could not have produced a similar effect on the whole globe.
Let us see what the historian of the Academy says on this subject anno
1718, p. 3. "The numerous remains of extensive inundations, and the
manner in which we must conceive mountains to have been formed,
sufficiently proves that great revolutions have happened to the surface
of the earth. As far as we have been able to penetrate we find little
else but ruins, wrecks, and vast bodies heaped up together and
incorporated into one mass, without the smallest appearance of order or
design. If there is some kind of regular organization in the terrestrial
globe it is deeper than we have been able to examine, and all our
researches must terminate in digging among the ruins of the external
coat, but which will still find sufficient employment for our
philosophers.
"M. de Jussieu found in the environs of St. Chaumont a great quantity of
slaty or foliated stones, every foliage of which was marked with the
impression of a branch, a leaf, or the fragment of a leaf of some plant:
the representations of leaves were exactly extended, as if they had been
carefully spread on the stone by the hand; this proves they had been
brought thither by the water, which always keeps leaves in that state:
they were in different situations, sometimes two or three together. It
may easily be supposed that a leaf deposited by water upon soft mud, and
afterwards covered with another layer of mud, imprints on the upper the
image of one of its two surfaces, and on the under the image of the
other; and on being hardened and petrified would appear to have taken
different impressions; but, however natural this supposition may be, the
fact is not so, for the two laminæ of stone bear impressions of the same
side of the leaf, the one in alto, the other in bas releaf. It was M.
Jussieu who made these observations on the figured stones of St.
Chaumont; to him we shall leave the explication, and pass to objects
which are more general and interesting.
"All the impressions on the stones of St. Chaumont are of foreign
plants; they are not to be found in any part of France, but only in the
East Indies or the hot climates of America; they are for the most part
capillary plants, generally of the species of fern, whose hard and
compact coat renders them more able to imprint and preserve themselves.
Some leaves of Indian plants imprinted on the stones of Germany appeared
astonishing to M. Leibnitz, but here we find the same wonderful affair
infinitely multiplied. There even seems in this respect to be an
unaccountable destination of nature, for in all the stones of St.
Chaumont not a single plant of the country has been found.
"It is certain, by the number of fossil-shells in the quarries and
mountains, that this country, as well as many others, must have formerly
been covered with the sea. But how has the American or Indian sea
reached thither? To explain this, and many other wonderful phenomena, it
may be supposed, with much probability, that the sea originally covered
the whole terrestrial globe: but this supposition will not hold good,
because how were terrestrial plants to exist? It evidently, therefore,
must have been great inundations which have conveyed the plants of one
country into the others.
"M. de Jussieu thinks, that as the bed of the sea is continually rising,
in consequence of the mud and sand which the rivers incessantly convey
there, the sea, at first confined between natural dykes, surmounted
them, and was dispersed over the land, and that the dykes were
themselves undermined by the waters and overthrown therein. In the
earliest time of the formation of the earth, when no one thing had taken
a regular form, prodigious and sudden revolutions might then have been
made, of which we no longer have examples, because the whole is now in
such a permanent state, that the changes must be inconsiderable and by
degrees.
"By some of these great revolutions the East and West Indian seas may
have been driven to Europe, and carried with them foreign plants
floating on its waters, which they tore up in their road, and deposited
gently in places where the water was but shallow and would soon
evaporate."
FOOTNOTES:
[220:A] Anno 1720; page 5.
[227:A] A kind of soft gravelly stone.
[233:A] On this subject see Stenon, Ray, Woodward, and others.
[234:A] See Shaw's Voyages, Vol. ii, pages 40 and 41.
[237:A] See Shaw's Travels.
[240:A] Thevenot, Vol. I, page 25.
[240:B] Voyage of Paul Lucus, Vol. II, page 380.
ARTICLE IX.
ON THE INEQUALITIES OF THE SURFACE OF THE EARTH.
The inequalities which are on the surface of the earth, and which might
be regarded as an imperfection to its figure, are necessary to preserve
vegetation and life on the terrestrial globe. To be assured of this, it
is only requisite to conceive what the earth would be if it was even and
regular. Instead of agreeable hills, from whence pure streams of waters
flow, to support the verdure of the earth; instead of those rich and
flourishing meadows, where plants and animals find agreeable
subsistence; a dismal sea would cover the whole globe, and the earth,
deprived of all its valuable qualities, would only remain an obscure and
forsaken planet, at best only destined for the abode of fishes.
But independent of moral considerations, which seldom form a proof in
philosophy, there is a physical necessity why the earth must be
irregular on its surface; for supposing it was perfectly regular in its
origin, the motion of the waters, the subterraneous fires, the wind, and
other external causes, would, in course of time, have necessarily
produced irregularities similar to those now seen.
The greatest inequalities next to the elevations of mountains, are the
depths of the ocean; this depth is very different even at great
distances from land; it is said there are parts above a league deep, but
those are few, and the most general depths are from 60 to 150 fathoms.
The gulphs bordering on the coasts are much less deep, and the straits
are generally the most shallow.
To sound the depths of the sea, a piece of lead of 30 or 40lb. is made
use of, fastened to a small cord; this is a good method for common
depths, but is not to be depended upon when the depth is considerable;
because the cord being specifically lighter than the water, after it has
descended to a certain degree, the weight of the lead and that of the
cord is no more than a like volume of water; then the lead descends no
longer, but moves in an oblique line, and floats at the same depth: to
sound great depths, therefore, an iron chain is requisite, or some
substance heavier than water. It is very probable that for want of
considering this circumstance, navigators tell us that the sea in many
places has no bottom.
In general, the profundities in open seas increase or diminish in a
pretty uniform manner, and commonly the farther from shore the greater
the depth; yet this is not without exception, there are places in the
midst of the sea where shoals are found, as at Abrolhos in the Atlantic;
and others where there are banks of a very considerable extent, as are
daily experienced by the navigators to the East Indies.
So likewise along shore the depths are very unequal, nevertheless we may
lay it down as a certain rule, that the depth there is always
proportionate to the height of that shore. It is the same in great
rivers, where the high shores always announce a great depth.