TIME.--GEOLOGICAL PHENOMENA.
Time, an element in Nature’s Operations--Geological
Science--Its Facts and Inferences--Nebular Hypothesis
applied--Primary Formations--Plutonic and Metamorphic
Rocks--Transition Series--Palæozoic Rocks--Commencement of
Organic Arrangements--Existence of Phosphoric Acid in Plutonic
Rocks--Fossil Remains--Coal Formation--Sandstones--Tertiary
Formations--Eocene, Miocene, and Pliocene Formations--Progressive
changes now apparent--General Conclusions--Physics applied in
explanation.
The influence of time, as an element, in producing certain structural
arrangements, by modifying the operations of physical force, under
whatever form it may be exerted, has scarcely been sufficiently
attended to in the examination of cosmical phenomena. Every particle
of matter is, as it were, suspended between the agencies to which
we have been directing our attention. Under the influences of the
physical powers, sometimes exerted in common, but often with a great
preponderance in favour of one of them, every accumulated heap of mud
or sand is slowly cohering, and assuming the form of a rock possessing
certain distinguishing features, as it regards lamination, cleavage, &c.
The minute particles of matter are necessarily but slightly influenced
by the physical forces: their action in accordance with the laws which
determine physical condition is manifested in an exceedingly modified
degree. But in all the operations of nature, what is deficient in
power is made up in time, and effects are produced during myriads
of ages, by powers far too weak to give satisfactory results by any
experiments which might be extended even over a century.
If, with the eye of a geologist, we take but a cursory glance over the
Earth, we shall discover that countless ages must have passed during
the progress of this planet to its present state. This is a fact
written by the finger of nature, in unmistakeable characters, upon the
mighty tablets of her mountains.
The superficial crust of the earth,--by which is meant only that film,
compared with its diameter, which is represented by a few miles in
depth--is composed of distinct mineral masses, exhibiting peculiar
physical conditions and a certain order of arrangement. These rocks
appear to have resulted from two dissimilar causes; in one class the
action of heat is evident, and in the other we have either the slow
deposition of matter suspended in water, or crystallization from
solution; an aqueous origin is indicated by peculiarities of formation
in all the more recent rocks.
There are few branches of science which admit of speculation to the
extent to which we find it carried in geology. The consequences of this
are shown in the popular character of the science. A few observations
are made over a limited area, and certain structural conditions are
ascertained, and at once the mind, “fancy free,” penetrates the
profound depths of the earth, and imagination, having “ample room
and verge enough,” creates causes by which every effect is to be
interpreted. Such students, generally ignorant of the first principles
of physics, knowing little of mineralogy, and less of chemistry, to
say nothing of palæontology, having none of the requisites for an
observer, boldly assume premises which are untenable, and think they
have explained a phenomenon,--given to the world a truth,--when they
have merely promulgated an unsubstantiated speculation, which may have
occasional marks of ingenuity, and but little else.
The carefully-made observations of those who, with unwearying industry,
have traversed hill and valley, marked and measured the various
characters, thicknesses, inclinations, and positions of rocks; who have
watched the influences of heat in changing, of water in wearing, and
the results of precipitation in forming, strata; who have traced the
mechanical effects of earthquake strugglings and of volcanic eruptions,
and, reasoning from an immense mass of accumulated facts, deduced
certain general conclusions,--are, however, of a totally different
character; and it is such observers as these who induced Herschel to
say truly, that “geology, in the magnitude and sublimity of the objects
of which it treats, undoubtedly ranks, in the scale of the sciences,
next to astronomy.”[231]
The origin of this planet is involved in great obscurity, which the
powers of the most gifted are unable to penetrate. It stands the work
of an Almighty and Eternal mind, the beginning of which we cannot
comprehend, nor can we define the period of its termination.
It may, probably, be safe to speculate that there was a time when
this globe consisted of only one homogeneous stratum. Whether
this remains,--whether, in our plutonic rocks, our granites, or
our porphyries, we have any indications of the primitive state of
the world, or whether numerous changes took place before even our
unstratified formations had birth, are questions we cannot answer. The
geologist looks back into the vista of time, and reckons, by phenomena,
the progress of the world’s mutations. The stratified formations
must have occupied thousands of ages; but before these were, during
a period extending over countless thousands, the unstratified rocks
may have been variously metamorphosed. It matters not whether we admit
the nebular hypothesis or not,--a time must have been when all these
bodies which now form the mass of this globe existed in the most simple
state. We have already shown that very remarkable changes in external
character and in chemical relations are induced, in the same simple
element, by its having been exposed to some peculiar and different
conditions; and already have we speculated on the probability that
the advance of science will enable us to reduce the numerous elements
we now reckon, to two or three. It is, therefore, by no means an
irrational thought (which must, however, be held in the light of a
pure conjecture), to suppose that at the beginning a mighty mass of
matter, in the most attenuated state, was produced in space, and was
gradually, under the influence of gravitation, of cohesive force, and
of chemical aggregation, moulded into the form of a sphere. Ascending
to the utmost refinement of physics, we may suppose that this mass was
of one uniform character, and that it became in dissimilar parts--its
surfaces and towards its centre--differently constituted, under the
influences of the same powers which we now find producing, out of the
same body, charcoal and the diamond, and creating the multitudinous
forms of organized creations. These conditions being established, and
carried to an extent of which, as yet, science has afforded us no
evidence, chemical intermixture may have taken place, and a new series
of compounds have been formed, which, by again combining, gave rise to
another and more complex class of bodies.
The foundation of the superficial crust of the earth appears to be
formed of a class of rocks which have resulted from the slow cooling
of an immense mass of heated matter. These rocks have been called
_igneous_; but are now more generally termed _Plutonic_ (such as
granites, syenites, &c.) Immediately above these, we find rocks which
have resulted by deposition from water. These masses, having been
exposed to the action of the heat below, have been considerably changed
in their character, and hence they are often called _metamorphic_;
but metamorphic rocks may, however, be of any age. The rocks formerly
termed the _transition_ series--from their forming the connecting link
between the earlier formations--are now, from the circumstance of their
being fossiliferous, classed under the general term of palæozoic rocks,
to distinguish them from the rocks in which no organic remains have
been found. Above these are found the secondary strata, and, still more
recently produced, we have a class now usually denominated the tertiary
formations. “Eternal as the hills” is a poetic expression, implying a
long duration; but these must, from the nature of things, eventually
pass away. The period of time necessary for the disintegration of a
granite hill is vastly beyond the powers of computation, according
to our conception of the ordinary bounds of finite things. But a
consideration of the results of a few years,--under the influence of
the atmosphere and the rains,--as shown in quantity of solid matter
carried off by the rivers, and deposited at their mouths, will tend to
carry conviction to every mind, that a degrading process is for ever in
action on the surface of the earth. The earth itself may be eternal,
but the surface is continually undergoing mutation, from various
causes, many of which we must briefly consider.[232]
In regarding geological phenomena, the absence of any fossil remains
has often been supposed to indicate a period previous to any organic
formations. The inorganic constituents of matter are probably of
prior origin to the organic combinations; the vessel was constructed,
upon which the organic creation was to float in space before any
vital organisms were created. The supposed evidences in favour of the
assumption that there was no organic life during the formation of the
oldest rocks we know, are in some respects doubtful; and we can well
understand that changes may have been induced in the earlier rock
formations, by heat or by other powers, quite sufficient to destroy all
traces of organized forms. It was long thought that phosphoric acid was
not to be detected in rocks which are regarded as of igneous origin;
and since this acid is peculiarly a constituent of organic bodies, this
has been adduced as a proof that the plutonic rocks must have existed
previously to the appearance of vegetable or animal life upon the
surface of the globe. The researches of modern chemists have, however,
shown that phosphoric acid is to be found in formations of granitic
origin, in porphyry, basalt, and hornblende rocks.[233] If, therefore,
we are to regard this substance as of organic origin, the rational
inference is against the speculation; but there is no more necessity
for supposing phosphorus to be formed in the animal economy than in
the mineral kingdom, from which it will probably be found the animal
obtained it.
Without attempting to enter into any account of the apparent progress
of life over the earth, it appears desirable that some description
should be given of the kinds of plants and animals which we know to
have existed at different epochs. We shall thus learn, at least, some
of the prevailing characteristics of the earth during its transitions,
and be in a better condition for applying our knowledge of physical
power to the explanation of the various geological phenomena.
Among the earliest races we have those remarkable forms, the
trilobites, inhabiting the ancient ocean.
These crustacea bear some resemblance, although a very remote one, to
the common wood-louse, and, like that animal, they had the power of
rolling themselves into a ball when attacked by an enemy. The eye of
the trilobite is a most remarkable organ; and in that of one species,
_Phacops caudatus_, not less than two hundred and fifty lenses have
been discovered. This remarkable optical instrument indicates that
these creatures lived under similar conditions to those which surround
the crustacea of the present day.
At the period of the trilobites of the Silurian rocks, all the animals
contemporaneous with them had the organs necessary for the preservation
of life in the waters.
Next in order of time to the trilobite, the most singular animals
inhabiting those ancient seas, whose remains have been preserved,
are the _Cephalopoda_, possessing some traces of organs which belong
to vertebrated animals. There are numerous arms for locomotion and
prehension, arranged in a centre round the head, which is furnished
with a pair of sharp, horny mandibles, embedded in powerful muscles.
These prehensile arms are provided with a double row of suckers, by
which the animal seized its prey. Of these cephalopodous animals there
are many varieties, but all of them appear to be furnished with powers
of rapid locomotion, and those with shells had an hydraulic arrangement
for sinking themselves to any depth of the seas in which, without
doubt, they reigned the tyrants.
Passing by without notice the numerous fishes, which appear to have
exhibited a similar order of progression to the other animals, we must
proceed to the more remarkable period when the dry land first began to
appear.
All the animals found in the strata we have mentioned are such as would
inhabit the seas; but we gradually arrive at distinct evidence of the
separation of the land from the water, and the “green tree yielding
seed” presents itself to our attention; not that the strata earlier
than this are entirely destitute of any remains indicating vegetable
growth, but those they exhibit are such as, in all probability, may be
referred to marine plants.
Those plants, however, which are found in the carboniferous series
are most of them distinguished by all the characteristics of those
which grow upon the land; we, therefore, in the mutilated remains of
vegetation left us in our coal-formations, read the history of our
early world.
Then the reed-like calamite bowed its hollow and fragile stems over
the edges of the lakes the tree-ferns grew luxuriantly in the shelter
of the hills, and gave a wild beauty to the humid valleys; the
lepidodendrons spread themselves in mighty forests along the plains,
which they covered with their curious cones; whilst the sigillariæ
extended their multitudinous branches, wreathing like serpents amongst
the luxurious vegetation, and embraced, with their roots (stigmariæ), a
most extensive space on every side.[234]
The seas and lakes of this period abounded with minute animals nearly
allied to the coral animals, which are now so actively engaged in the
formation of islands in the tropical and southern seas. During the ages
which passed by without any remarkable disturbance of the surface of
the earth, the many bands of mountain limestone were formed by the
ceaseless activity of these minute architects. Encrinites (creatures
in some respects resembling star-fish) existed in vast numbers in the
oceans of this time; and the great variety of bivalve shells, and those
of a spiral character, discovered in the rocks of this period, show the
waters of the newer palæozoic period to have been instinct with life.
In the world then, as it does now, water acting on the dry land
produced remarkable changes. We have evidence of extensive districts
over which the most luxuriant vegetation must have spread for
ages,--from the remains of plants in every state of decay,--which we
find went to form our great coal-fields. These, by some changes in the
relative levels of land and water, became covered with this fluid;
and over this mass of decaying organic matter, sand and mud were for
ages being deposited. At length, rising above the surface, it becomes
covered with vegetation, which is, after a period, submerged; the same
deposition of sand and mud again takes place, it is once more fitted
for vegetable growth, and thus, cycle after cycle, we see the dry land
and the water changing places with each other. This will be evident
to every one who will carefully contemplate a section of one of the
coal-fields of Great Britain. We find a stratum of coal lying upon
a bed of under clay, and above it an extensive stratum of shale or
sandstone, probably formed by the denudation of the neighbouring hills;
and in this manner we have many strata of coal, shale, clay, ironstone,
and sandstone alternating with each other; the coal-formations of the
South Wales coal-field having the extraordinary thickness of 1500 feet.
The lowest bed of this extensive series must at one time have been
exposed as the surface of the country.
Ascending in the series, we have now formations of a more recent
character, in which fishes of a higher order of organization, creeping
and flying saurians, crocodiles and lizards, tortoises, serpents, and
frogs, are found. The lias formations (a term corrupted from _layers_),
consisting of strata in which an argillaceous character prevails, stand
next in series. In these we have animals preserved in a fossil state,
of a distinguishingly different character from those of the inferior
strata. We meet with extended beds of pentacrinites, some inches in
thickness; and their remains are often so very complete that every part
of the skeleton can be made out, although so complicated that it cannot
consist of less than 150,000 parts. In these formations we often find
the curiously beautiful remains of the ammonites, of which a great
variety have been discovered. Of the belemnites--animals furnished with
the shell and the ink-bag of the cuttle-fish, with which it darkened
the water to hide itself from enemies, numerous varieties have also
been disentombed, with the ink-bag so well preserved, that the story of
the remarkable fossil has been written with its own ink. In addition to
these we find nautili; and sixty species of extinct fishes have been
described by Agassiz from the lias of Lyme Regis alone.
When these rocks were in the progress of formation, there existed the
ichthyosaurus, or fish-lizard, which appears, in many respects, to have
resembled the crocodile of the Nile. It was a predatory creature of
enormous power, and must have been the tyrant and terror of the seas
which it inhabited. Its alligator-like jaws, its powerful eye, its
fish-like fins, and turtle-like paddles, were all formed to facilitate
its progress as a destructive minister. The plesiosaurus was, if
possible, a still more extraordinary creation. To the head of a lizard
was united an enormously long neck, a small and fish-like body, and the
tail of a crocodile: it appears formed for existence in shallow waters,
so that, when moving at the bottom, it could lift its head above the
surface for air, or in search of its food. The flora of this period
must have been extensive; and it resembled the vegetation which exists
at present in Tropical regions.
We pass now to a new epoch, which is well distinguished by its animals
from all that had preceded it. Races of reptiles still have place upon
the earth, and we have now the megalosaurian remains; these animals
possessing a strength and rapacity which would render them objects of
terror as well as astonishment, could they be restored to the world
which they once ravaged. An enormous bat-like creature also existed
at this time--the pterodactyl--which, in the language of Cuvier, was,
“undoubtedly, the most extraordinary of all the beings of whose former
existence a knowledge is granted to us, and that which, if seen alive,
would appear most unlike anything that exists in the present world.”
“You see before you,” says the same writer, “an animal which, in all
points of bony structure, from the teeth to the extremities of the
nails, presents the well-known saurian characteristics, and of which no
one can doubt that its integuments and soft parts, its scaly armour and
its organs of circulation and reproduction, are likewise analogous. But
it was, at the same time, an animal provided with the means of flying;
and, when stationary, its wings were probably folded back like those
of a bird, although, perhaps, by the claws attached to its fingers, it
might suspend itself from the branches of trees.”[235]
From the disintegration of the older rocks have no doubt arisen those
formations which are known as the oolitic series. In these strata are
preserved the remains of plants and animals more resembling those which
now exist upon the earth; and, for the first time,--unless the evidence
of the footsteps of birds on the new red sandstone of America be
accepted,--we meet with the remains of the feathered tribes.
In these formations we discover animals belonging to the class
Mammalia,--the amphitherium and the phascolotherium,--which appear
to have resembled, in many respects, the marsupial animals of New
Holland.[236]
The wealden formations, which are the next in order of position, are a
series of clays and sands, with subordinate beds of limestone, grit,
and shale. These have, in some instances, been formed in the sea; but
they are usually regarded as fresh-water deposits. All the older rocks
bear evident marks of marine origin, unless some of the coal-measure
strata may be regarded as otherwise; but nearly all the wealden series
contain the remains of land, fresh-water, and estuary animals, and of
land vegetables. The creatures which we discover, preserved, to tell
the history of this period, are numerous, and have marked peculiarities
to distinguish them from those already described, or from any now
existing on the earth. We find land saurians of a large kind, and
animals of all sizes; even insects, of which a great variety are found
in the wealds. The remarkable iguanodon was an animal which, even by
the cautious measurement of Professor Owen, must have been at least
twenty-eight feet long; and this enormous creature was suspected, by
Cuvier, and has been proved by Owen, to have been an “herbivorous
saurian for terrestrial life.”[237] Dr. Mantell calculates that no
less than seventy individuals of the iguanodon of all ages have come
under his notice; and the bones of a vast number of others must have
been broken up by the workmen in the few quarries of Tilgate grit;
so that these creatures were by no means rare at the period of their
existence.[238]
The uppermost of these secondary formations is the cretaceous or chalk
group, which spreads over a large portion of south-eastern England, and
is met with in all parts of Europe. This chalk, which is a carbonate
of lime, appears to have been slowly precipitated from tranquil water,
as, according to Sir Henry De la Beche, organic remains are beautifully
preserved in it. Substances of no greater solidity than common sponges
retain their forms, delicate shells remain unbroken, fish even are
frequently not flattened, and altogether we have the appearances
which justify us in concluding that, since these organic exuviæ were
entombed, they have been protected from pressure by the consolidation
of the rock around them.[239]
Beneath the chalk exists what has been called, from its colour--derived
from a silicate of the protoxide of iron,--green sand, and was, no
doubt, formed by deposition from the same water in which the carbonate
of lime was suspended,--the green sand falling to the bottom more
readily from its greater specific gravity. “The tranquillity,” observes
Sir Henry De la Beche, “which seems to have prevailed during this great
accumulation of siliceo-calcareous matter, whether it may have been
a deposit from water, in which it was mechanically suspended, partly
the work of living creatures, or in a great measure chemical, is very
remarkable.”[240]
In the chalk, the remains of the leaves of dicotyledonous plants
and fragments of wood are found more abundantly than in the earlier
strata, many of which are marked with the perforations of marine
worms, indicating that they had floated for some time in the ocean.
It should, however, be remembered, that these are not the first
indications of vegetable life,--leaves have been found in the new red
sandstone; and the flora of the coal formation must not be forgotten.
The manner in which silica has deposited itself on organic bodies--such
as the sponges--is curious; the whole of the organized tissue being
often removed, and flint having taken its place. Flints formed by
such a process as this abound in the upper chalk. The association
of carbon and silicon, combined with oxygen, as we find them in the
cretaceous formations, is most interesting, and naturally gives rise
to some speculation on the relation of these two elements. Both carbon
and silicon, as has been already shown, exist in several allotropic
conditions; and, although the statements made by Dr. Brown relative
to the conversion of carbon into silicon are proved to be grounded on
experimental error, it is not improbable that a very intimate relation
may exist between these elements.[241] The probability is, that the
sponge animal has the power of secreting silica to give strength
to its form. “Many species,” says Rymer Jones, speaking of recent
sponges, “exhibiting the same porous structure, have none of the
elasticity of the officinal sponge--a circumstance which is due to the
difference observable in the composition of their skeletons or ramified
frame-work. In such the living crust forms within its substance
not only tenacious bands of animal matter, but great quantities of
crystallized spicula, sometimes of a calcareous, at others of a
siliceous, nature.” Thus, a frame of siliceous matter being formed by
the living animal, a deposition of the same substance is continued
after death.
Sea-urchins and star-fish, and numerous fossil shells, are found in
these beds, which, however, differ materially from the remains of the
same animals found in the earlier formations. A vast number of new
species and genera of fish are also discovered in the chalk.
Nearly all the animals and plants which existed up to this period are
now extinct, although they have some imperfect representatives at the
present day.
The uppermost group, which has been called the supercretaceous or
tertiary formation, appears in our island to have been formed during
four great eras, as we find fresh-water deposits alternating with
marine ones. The term _eocene_, which is the first or oldest deposit;
_miocene_, which is the second; _pliocene_, which is the third; and the
_newer pliocene_,--which is the fourth and last, have been applied to
these formations, the names referring to the respective proportions of
existing species found among their fossil shells.[242]
All these formations show distinct evidence of their having been
deposited from still or slowly-flowing deep waters. Thus the eocene
appears in the Paris basin,--formed clearly at an estuary, in which
are mingled some interesting fresh-water deposits;--in the lacustrine
formations in Auvergne; also at Aix; and in the north of Italy. It
appears probable that, in the formations generally termed eocene, both
fresh-water and marine deposits have been confounded, and several
formations of widely-different eras regarded as the result of one. We
have not yet been furnished with any distinct and clear evidence to
show that the deposits of the Paris basin, and those of Auvergne,
are of the same age. At all events, it is sufficient for our present
purpose to know that they are the result of actions which are now as
general as they were when the plastic clay of Paris, and its sulphate
of lime, or the London clay, were slowly deposited.
As a general conclusion, we may decide that, at the eocene period,
existing continents were the sites of vast lakes, rivers, and
estuaries, and were inhabited by quadrupeds, which lived upon
their thickly-wooded margins. Many remains, allied to those of the
hippopotamus, have been found in the subsidences of this period.
Examples of the miocene or middle tertiary era are to be found in
Western France, over the whole of the great valley of Switzerland, and
the valley of the Danube. In these deposits we find the bones of the
rhinoceros, elephant, hippopotamus, and the dinotherium, an extinct
animal, possessing many very distinguishing features.[243]
The pliocene period has been termed the age of elephants, and is most
remarkable for the great mastodons and gigantic elks, with other
animals not very unlike those which are contemporaneous with man.
In the superficial layers of the earth, the diluvium, alluvium, peat
and vegetable soil, we have a continuation of the history of the
mutations of our globe and of its inhabitants, which has been here so
briefly sketched. They bring us up to the period when man appeared in
the world, since whose creation it is evident no very extensive change
has been produced upon the surface. We have viewed the phenomena of
each great epoch, marked as they are by new creations of organized
beings, and it would appear as if, through the whole series, from
the primary rocks up to the modern alluvial deposits, a progressive
improvement of the earth’s surface had been effected, to fit it at last
for the abode of the human race.
Thus have we preserved for us, in a natural manner, evidences which, if
we read them aright, must convince us that the laws by which creation
has ever been regulated are as constant and unvarying as the Eternal
mind by which they are decreed. Our earth, we find, by the records
preserved in the foundation-stones of her mountains, has existed
through countless ages, and through them all exhibited the same active
energies that prevail at the present moment. By precisely similar
influences to those now in operation, have rocks been formed, which,
under like agencies, have been covered with vegetation, and sported
over by, to us, strange varieties of animal life. Every plant that
has grown upon the earliest rocks which presented their faces to the
life-giving sun, has had its influence on the subsequent changes of our
planet. Each trilobite, each saurian, and every one of the mammalia
which exist in the fossil state, have been small laboratories in which
the great work of eternal change has been carried forward, and, under
the compulsion of the strong laws of creation, they have been made
ministers to the great end of forming a world which might be fitting
for the presence of a creature endued with a spark taken from the
celestial flame of intellectual life.
For a few moments we will return to a consideration of the operations
at present exhibiting their phenomena, and examine what bearing they
have upon our knowledge of geological formations.
During periods of immense, but unknown, duration, the ocean and the dry
land are seen to have changed their places. Enormous deposits, formed
at the bottom of the sea, are lifted by some mechanical, probably
volcanic, force, above the waters, and the land, like the ocean
surrounding it, teems with life. This state of things lasts for ages;
but the time arrives when the ocean again floods the land, and a new
state of things, over a particular district, has a beginning.
It must not be imagined that the changes which we have spoken of, as if
they were the result of slow decay and gradual deposit, were effected
without occasional violent convulsions. Many of the strata which
were evidently deposited at the bottom of the sea, and, of course,
as horizontal beds, are now found nearly vertical. We have evidence
of strata of immense thickness having been subjected to forces that
have twisted and contorted them in a most remarkable manner. Masses of
solid rock, many thousand feet deep, are frequently bent and fractured
throughout their whole extent. Mountains have been upheaved by internal
force, and immense districts have suddenly sunk far below their usual
level. By the expansive force due to that temperature which must be
required to melt basaltic and trap rocks, the whole of the superficial
crust of a country has been heaved to a great height, immense fissures
have been formed by the breaking of the mass, and the melted matter has
been forced through the opening, and overflowed extensive districts, or
volcanoes have been formed, and wide areas have been buried under the
ashes ejected from them. With the cause of these convulsions we are at
present unacquainted.
We have evidence of the extent to which these forces may be exerted, in
the catastrophes which have occurred within historical times, and which
have happened even in our own day. Herculaneum and Pompeii, buried
under the lava and ashes of Vesuvius, in an hour when the inhabitants
of these cities were unprepared for such a fearful visitation,--the
frightful earthquakes which have, from time to time, occurred in South
America--are evidences of the existence of hidden forces which shake
the firm-set earth. Similar ravaging catastrophes may have often
occurred, and, involving cataclysms, swept the surface to produce the
changes we detect over every part of the earth, compared with which
the earthquakes and floods of history are but trivial things. Evidence
has been adduced, to show that the mountains of the Old World may
have approached in height the highest of the Andes or Himalayas, and
these have not been destroyed by any sudden effect, but by the slow
disintegrating action of the elements.[244] All these phenomena are
now in progress: the winds and the rains wear the faces of the exposed
rock; their _débris_, mixed with decayed vegetable and animal matter,
are washed off from the surface, and borne away by the rivers, to be
deposited in the seas. Thus it is that the great delta of the Ganges
is formed, and that a continual increase of matter is going on at the
mouths of rivers. The Amazon, the Mississippi, and other great rivers,
bear into the ocean, daily, thousands of tons of matter from the
surface of the earth.[245] This is, of course, deposited at the bottom
of the sea, and it must, in the process of time, alter the relative
levels of the ocean and the land. Islands have been lifted by volcanic
power from the bottom of the sea, and many districts in South America
have been depressed by the same causes.
Changes as extensive have been, in all probability, effected by forces
“equally or more powerful, but acting with less irregularity, and so
distributed over time as to produce none of those interregnums of
chaotic anarchy which we are apt to think (perhaps erroneously) great
disfigurements of an order so beautiful and harmonious as that of
nature.”[246] These forces are, without doubt, even now in action.
Had it not been for these convulsive disturbances of the surface,
the earth would have presented an almost uniform plain, and it would
have been ill-adapted for the abode of man. The hills raised by the
disturbances of nature, and the valleys worn by the storms of ages,
minister especially to his wants, and afford him the means of enjoyment
which he could not possess had the surface been otherwise formed. The
“iced mountain tops,” condensing the clouds which pass over them, send
down healthful streams to the valleys, and supply the springs of the
earth, thus securing the fertility and salubrity of the distant plains.
The severities of climate are mitigated by these conditions, and both
the people of the tropics and those dwelling near the poles are equally
benefited by them.
Gravitation, cohesion, motion, chemical force, heat, and electricity,
must, from that hypothetical time when the earth floated a cloud of
nebulous vapour, in a state of gradual condensation up to the present
moment, have been exercising their powers, and regulating the mutations
of matter.
When the dry land was beneath the waters, and when darkness was upon
the face of the deep, the same great operations as those which are
now in progress in the depths of the Atlantic, or in the still waters
of our inland lakes, were in full activity. At length the dry land
appears; and--mystery of mysteries--it soon becomes teeming with life
in all the forms of vegetable and animal beauty, under the aspect of
the beams of a glorious sun.
Geology teaches us to regard our position upon the earth as one far
in advance of all former creations. It bids us look back through
the enormous vista of time, and see, shining still in the remotest
distance, the light which exposes to our vision many of nature’s holy
wonders. The elements which now make up this strangely beautiful fabric
of muscle, nerves, and bone, have passed through many ordeals, ere yet
it became fashioned to hold the human soul. No grain of matter has been
added to the planet, since it was weighed in a balance, and poised with
other worlds. No grain of matter can be removed from it. But in virtue
of those forces which seem to originate in the sun, “the soul of the
great earth,” a succession of new forms has been produced, as the old
things have passed away.
Under the forces we have been considering, acting as so many contending
armies, matter passes from one condition to another, and what is now
a living and a breathing creature, or a delicate and sweetly-scented
flower, has been a portion of the amorphous mass which once lay in the
darkness of the deep ocean, and it will again, in the progress of time,
pass into that condition where no evidences of organization can be
found,--again, perhaps, to arise clothed with more exalted powers than
even man enjoys.
When man places himself in contrast with the Intelligences beyond him,
he feels his weakness; and the extent of power which he can discover at
work, guided by a mysterious law, is such, that he is dwarfed by its
immensity. But looking on the past, surveying the progress of matter
through the inorganic forms up to the higher organizations, until at
length man stands revealed as the chief figure in the foreground of the
picture, the monarch of a world on which such elaborate care has been
bestowed, and the absolute ruler of all things around him, he rises
like a giant in the conscious strength of his far-searching mind. That
so great, so noble a being, should suffer himself to be degraded by the
sensualities of life to a level with the creeping things, upon which he
has the power to tread, is a lamentable spectacle, over which angels
must weep.
The curious connection between the superstitions of races, the
traditionary tales of remote tribes, and the developments of the truths
of science, are often of a very marked character, and they cannot but
be regarded as instructive. In the wonders of “olden time” fiction has
ever delighted; and a thousand pictures have been produced of a period
when beings lived and breathed upon the earth which have no existence
now.
Hydras, harpies, and sea-monsters, figure in the myths of antiquity.
In the mythology of the northern races of Europe we have fiery flying
dragons, and Poetry has placed these as the guardians of the “hoarded
spirit” and protectors of the enchanted gold.
Through the whole of the romance period of European literature,
nothing figures but serpents, “white and red,” toiling and fighting
underground,--thus producing earthquakes, as in the story of Merlin
and the building of Stonehenge. Flying monsters, griffins and others,
which now live only in the meaningless embellishments of heraldry,
appear to have been conceived by the earlier races of men as the
representatives of power. Curious is it, too, to find the same class
of ideas prevailing in the East. The monster dragons of the Chinese,
blazoned on their standards and ornamenting their temples;--the
Buddaical superstition that the world is supported on a vast elephant,
which stands on the back of a tortoise, which again rests on a serpent,
whose movements produce earthquakes and violent convulsions;--the rude
decorations also of the temples of the Aztecs, which have been so
recently restored to our knowledge by the adventurous travellers of
Central America,--all give expression to the same mythological idea.
Do not these indicate a faint and shadowy knowledge of a previous
state of organic existence? The process of communion between man of
the present, and the creations of a former world, we know not; it is
mysterious, and for ever lost to us. But even the most ignorant and
uncultivated races of mankind have figured for themselves the images
of creatures which, whilst they do really bear some resemblance to
things which have for ever passed away, do not, in the remotest degree,
partake of any of the peculiarities of existing creations.
The ichthyosaurus, and the plesiosaurus, and the pterodactylus, are
preserved in the rude images of harpies, of dragons, and of griffins;
and, although the idea of an elephant standing on the back of a
tortoise was often laughed at as an absurdity, Captain Cautley and
Dr. Falconer at length discovered in the hills of Asia the remains of
a tortoise in a fossil state of such a size that an elephant could
easily have performed the feat.[247]
Of the ammonites, we have more exact evidence; they were observed by
our forefathers, and called by them snake-stones. According to the
legends of Catholic saints they were considered as possessing a sacred
character:--
“Of these and snakes, each one
Was changed into a coil of stone
When holy Hilda prayed.”
And in addition to this petrifying process, one of decapitation is said
to have been effected; hence the reason why these _snake-stones_ have
no heads.
We also find, in the northern districts of our island, that the name of
“St. Cuthbert’s beads” is applied to the fossil remains of encrinites.
Thus we learn that, to a great extent, fiction is dependent upon
truth for its creations; and we see that when we come to investigate
any wide-spread popular superstition, although much distorted by the
medium of error through which it has passed, it is frequently founded
upon some fragmentary truth. There are floating in the minds of men
certain ideas which are not the result of any associations drawn from
things around; we reckon them amongst the mysteries of our being. May
they not be the truths of a former world, of which we receive the dim
outshadowing in the present, like the faint lights of a distant Pharos,
seen through the mists of the wide ocean?
Man treads upon the wreck of antiquity. In times which are so long
past, that the years between them cannot be numbered by the aids of
our science, geology teaches us that forms of life existed perfectly
fitted for the conditions of the period. These performed their offices
in the great work; they passed away, and others succeeded to carry
on the process of building a world for man. The past preaches to
the present, and from its marvellous discourses we venture to infer
something of the yet unveiled future. The forces which have worked
still labour: the phenomena which they have produced will be repeated.
Ages on ages slowly pass away,
And nature marks their progress by decay.
The plant which decks the mountain with its bloom,
Finds in the earth, ere long, a damp dark tomb:
And man, earth’s monarch, howe’er great and brave--
Toils on--to find at last a silent grave.
The chosen labours of his teeming mind
Fade by the light, and crumble ’neath the wind;
And e’en the hills, whose tops appear to shroud
Their granite peaks deep in the vapoury cloud,
Worn by tempests--wasted by the rains,
Sink slowly down to fill wide ocean’s plains.
The ocean’s breast new lands again display,
And life and beauty drink the light of day:
The powers which work at great creation’s wheel,
Will from the wrecks of matter still reveal
New forms of wondrous beauty--which will rise
Pure as the flame of love’s young sacrifice,
Beaming with all the pristine hues of youth,
Robed by the day, and crowned by holy truth.
FOOTNOTES:
[231] _Preliminary Discourse_; Sir J. F. W. Herschel. Lardner’s Cabinet
Cyclopædia.
[232] _Geological Researches_; by Sir Henry De la Beche, C.B.
(_Degradation of Mountains_, p. 167.) _Geological Manual_, p. 184.
_Principles of Geology_; by Sir Charles Lyell, 7th Edition, p. 150,
686. _On the Denudation of South Wales, and the adjacent countries of
England_; by Professor Andrew Ramsay; Memoirs of the Geological Survey
and Museum of Practical Geology, vol. i. p. 297.
[233] Fownes, _On the Existence of Phosphoric Acid in Rocks of Igneous
Origin_; Phil. Trans. 1844, p. 53. Nesbitt, _Quarterly Journal of the
Chemical Society_.
[234] _On the Vegetation of the Carboniferous Period as compared
with that of the present day; On some peculiarities in the structure
of Stigmaria; Remarks on the Structure and Affinities of some
Lepidostrobi_: by Dr. Hooker; Memoirs of the Geological Survey, &c.,
vol. ii. pp. 387, 431, 440.
[235] See Owen, Quarterly Journal of the Geological Society, No. 6,
p. 96. Dr. Buckland, Geological Transactions, vol. iii. p. 220. _The
Wonders of Geology_: by Dr. Mantell, vol. ii. p. 493.
[236] _Report on British Fossil Mammalia_: by Richard Owen, Esq.,
F.R.S.; British Association Reports, vols. xi. xii.
[237] _Notice on the Iguanodon, a newly discovered fossil reptile from
the sandstone of Tilgate Forest, in Sussex_: by Gideon Mantell, Esq,
F.R.S., &c.; Philosophical Transactions, vol. cxv. p. 179. _On the
Structure of Teeth, &c._; by Professor Owen.
[238] Dr. Mantell, _Wonders of Geology_. _Geology of the South-east of
England._
[239] _Geological Researches_; _Geological Manual_; by Sir Henry Thos.
De la Beche, C.B., &c.
[240] Ibid.
[241] _Experimental Researches on the production of Silicon from
Paracyanogen_: by Samuel Brown, M.D.; Transactions of the Royal Society
of Edinburgh, vol. xv. p. 229. _Experiments on the alleged conversion
of Carbon into Silicon_: by R. H. Brett, Ph.D., and J. Denham Smith,
Esq.; Philosophical Magazine, vol. xix. p. 295, New Series. See also
Dr. Brown’s reply to the above, ibid, p. 388.
[242] _Geology, Introductory, Descriptive, and Practical_: by Prof.
Ansted, vol. ii. p. 22.
[243] _The Wonders of Geology_: by Dr. Mantell, vol. i. p. 162.
_Bridgewater Treatise_: by Dr. Buckland. Dr. J. J. Kemp, and Dr. A.
V. Klipstein, _On the Dinotherium_; Darmstadt, 1836. Cuvier and De
Blainville have also carefully described the fossil remains of this
animal.
[244] See Professor Ramsay’s memoir _On Denudation_: Memoirs of the
Geological Survey of Great Britain.
[245] “The distances to which river water, more or less charged with
detritus, would flow over sea-water, will depend upon a variety
of obvious circumstances. Captain Sabine found discoloured water,
supposed to be that of the Amazons, three hundred miles distant in
the ocean from the embouchure of that river. It was about 126 feet
deep. Its specific gravity was = 1·0204, and the specific gravity of
the sea-water = 1·0262. This appears to be the greatest distance from
land at which river water has been detected on the surface of the
ocean. If rivers, containing mechanically suspended detritus, flowed
over sea-water in lines which, in general terms, might be called
straight, the deposit of transported matter which they carried out
would also be in straight lines. If, however, they be turned aside
by an ocean current, as was the case with that observed by Captain
Sabine, the detritus would be thrown, and cover an area corresponding
in a great degree with the sweep which the river has been compelled
to make out of the course, that its impulse, when discharged from its
embouchure, might lead it to take: supposing the velocity with which
this river-water was moving has been correctly estimated at about
three miles per hour, it is not a little curious to consider that the
agitation and resistance of its particles should be sufficient to keep
finely comminuted solid matter mechanically suspended, so that it
would not be disposed freely to part with it, except at its junction
with the sea-water over which it flows, and where, from friction, it
is sufficiently retarded. So that a river, if it can preserve a given
amount of velocity flowing over the sea, may deposit no very large
amount of mechanically suspended detritus in its course from the
embouchure, where it is ultimately stopped. Still, however, though the
deposit may not be so abundant as at first sight would appear probable,
the constant accumulation of matter, however inconsiderable at any
given time, must produce an appreciable effect during the lapse of
ages.”--Sir Henry De la Beche’s _Geological Researches_, p. 72.
[246] Sir J. F. W. Herschel: _Preliminary Treatise_.
[247] _Fauna Antiqua Sivalensis. Being the Fossil Zoology of the
Sewalik Hills in the North of India_: by Hugh Falconer and Proby T.
Cautley. 1844.