railway-cutting has been before now a fatal employment; and digging
pits forty feet deep into the mud of the Nile is an operation attended
with difficulties peculiar to itself. Here, however, in Torquay, close
at hand, we possess a register of time as compact, as accessible, as
genuine, as the Library of the British Museum. Limestone, it is well
known, is formed beneath the waters of the sea. When it appears above
the sea-level, it must have been upheaved from its ocean-bed. How long
a period must be allowed for the hill which contains Kent’s cavern to
have been formed by this double process, may be left for the present
to the imagination. How long a time elapsed before the cavern was
burst open or eaten out from the solid limestone, we will not enquire.
Thanks to the diligent exploration of it; thanks to the unwearied
courtesy of its scientific curators[51], the contents of the cavern,
or at least a portion of them, are now well known. Not only do they
embrace the remains of animals not now existing in England, but they
embrace the remains of animals long since lost to the globe. With these
are mingled the products of human intelligence, the weapons of the
savage. The cave-earth which, as well as the stalagmite, contains these
relics of a most remote antiquity, is itself permeated with films of
stalagmite, a conclusive proof of its gradual introduction. Over the
lower portions have been formed in succession three solid stalagmitic
floors, remnants of which have quite lately been discovered still
imbedded in the cavern[52]. Let us for a moment consider what this
implies. If we transport ourselves to Matlock Bath in Derbyshire, for
the small fee of a penny, any one of its ‘petrifying wells’[53] will
be open to our inspection. In these curious grottoes whatever object
you please, natural or artificial, be it skull or the cap that once
covered it, be it basket or bird, or shell or leaf, may be encrusted
with a coating of stalagmite. The inexperienced visitor would like to
place an object in the well, and to wait while the ‘petrifying’ waters
do their work. He is surprised to find that in that case he must wait
and watch for months and years, while the slow persevering stream falls
upon his treasure with its ceaseless drip, drip, drip, and that the
work so slowly accomplished would not be accomplished at all if the
flowing of the stream were hastened. Imagine, then, in this famous
cavern of ours what an interminable song, though an intermittent one,
must have been sung with this drip, drip, drip, through ages and ages,
to produce, as in one place it has done, a solid stalagmitic mass full
twelve feet in thickness. Now, according to Usher’s chronology, we have
seventeen centuries from Adam to the Flood, and twenty-three centuries
from the Flood to the age of Julius Cæsar. If this chronology is to
be accepted, Kent’s cavern must have been filled either in the first
period or in the second. As the same arguments will apply to each, let
us assume that the second or longer period sufficed for this purpose,
and see what further admissions this assumption will involve. We have
three and twenty centuries at our disposal. At the end of that time
we know historically that Britain was occupied by tribes more or less
savage, some of them going about almost naked, destitute of almost
all the arts of civilization. We are to imagine the ancestors of this
wild race migrating from Asia and slowly pioneering their way to the
western limits of Europe. Necessity is the mother of invention; but
these men in their difficult adventurous travel through unknown seas
and pathless jungles tenanted by dangerous beasts, learn only how to
forget. They forget the use of brass and iron, and take to weapons and
tools of flint; they give up tillage; they give up building strong
towers, and shelter themselves in wooden huts or caves and dens of the
earth. The climate of Western Asia is warm and sunny, that of England
often, and in many parts, bleak and foggy and cold; therefore these
intelligent children of Noah, in order perhaps to harden themselves
in the process of acclimatization, as they force their way into the
fog and mist, instead of keeping or assuming the flowing robes of the
Asiatic, exchange their garments, at any rate in battle, for a wash of
paint. How interesting it would be to have the family portraits of a
Highland clan from the earliest times, showing how they gradually made
it fashionable to do without the various articles of clothing which one
by one they have been induced to resume[54]! During the same epoch,
within the same limits of time, migrating also from the warm regions
of Asia, came elephants and lions, hyenas and bears, the rhinoceros
and the elk. Little recked they then of change of climate, which now
they so ill endure. They prowled all over Europe; they swam across the
English Channel. Yet before the historical period begins in Gaul and
Britain, most of these species had had time not only to make their way
thither, not only to nourish and abound in these habitations, but to
die out and to be forgotten. We know for certain that elephants once
roamed over Devon. Did they succumb to the flint weapons of the savage?
Was the same savage able to extirpate the hyena and the lion, though
the representatives of those fierce beasts still partially set us at
defiance in India, notwithstanding the rifles and gunpowder of modern
civilization? Let us imagine that within the specified time all that
has been mentioned could have happened, and that some of the animals,
such as the woolly rhinoceros, had time to assume the characters of
northern species, or that the climate had time for vast changes and
alterations, or that the winds perhaps in those days blew hot and
cold with the same breath so as to suit arctic and tropical species
indifferently;--we must imagine further that within the same limits the
three floors of stalagmite could have been formed in succession, and
two of them successively broken up. They must have been formed, not
during the whole of the period, but only during that part of it which
_followed_ the introduction into Britain of wild beasts, and of men who
used flint weapons; for one unmistakeable weapon of human manufacture,
and innumerable bones of the great old cave bear have been found within
the rock-like breccia of stone and stalagmite and cave-earth, some feet
below both the floors of more recent formation[55]. The longer the
period, therefore, we allow for the migration from the East and the
dying out of civilized life, the shorter is the period left for the
stalagmitic formation. Yet probably the whole twenty-three centuries
would not suffice for the formation of one of the floors; how much less
could a fraction of the period suffice to form all three, and to supply
the intervals during which, through some change of circumstances, the
cave-earth was accumulating, and consequently no solid floor being
formed.
At Matlock the drip is continuous, being supplied by a stream, and not
being, as in Kent’s cavern, dependent on the chances of the rainfall
and the quantity of water that may percolate through a limestone roof.
At Matlock, for purposes of trade, it is an object that a coating of
stalagmite should be formed as quickly as possible. With this view the
water is allowed to fall at the rate of fifty or sixty drops a minute,
the drip being maintained at numerous points simultaneously. At Matlock
we may roughly estimate that an inch of stalagmite would require four
years for its formation, so that twelve feet and a half would require
six hundred years. In Kent’s cavern, on the other hand, the drip is
often interrupted. There is no commercial interest at hand to regulate
the speed in the most advantageous manner, so that it falls sometimes
too quickly and sometimes too slowly. The points at which it falls are
few and far between. It cannot reasonably be supposed in any year to
produce even a twentieth of the effect we have estimated for the drip
at Matlock. In other words, the two later floors of the cavern would
alone require a period of twelve thousand years for their formation.
Even at this rate the cavern would probably have been so extremely damp
and uncomfortable that no men or beasts would have chosen it for a
shelter in rainy weather.
But the cavern inscriptions make it as certain as can be that the rate
of speed here allowed for the formation of stalagmite is vastly too
high, and therefore that the time allowed for the formation is vastly
too low. The famous inscription of 1688 was shown to me a few days
back[56]. It was at that very time wet with the drip from the cavern
roof, a drip falling at the rate of thirty-four drops a minute. If
the date were really cut in the year 1688 (and there is no reason to
suppose that it was not), by our first calculation more than two inches
of stalagmite ought to have formed over it. Instead of which there is
but a thin veneer, a veneer that was observed upon it more than forty
years ago, and which has not in all those forty years increased enough
to make such a description of it inappropriate. If the date 1615 be
authentic, over which, in the opinion of the superintendents of the
exploration, not one-eighth of an inch of stalagmite has been formed
in more than two centuries and a-half, at the same rate of progression
twelve feet and a-half of stalagmite would demand for its formation
three hundred thousand years.
This cavern by itself, therefore--this one little crack in the
outermost rind of the earth’s surface--proves a comparatively immense
antiquity for the existence of organic life and of human beings upon
the globe. But to compare the antiquity of the cavern contents with
the antiquity of the limestone formation in which they are contained
is positively beyond any intelligible numerical measurement. Yet
the limestone formation itself is filled with the relics of living
creatures, and in some parts, if not in all, is one gigantic mass of
such remains.
In cliffs of sea-shore and river, in railway-cuttings, in mine-shafts
and quarries, we may often see layers of the earth’s crust in the
order of their original deposition. Except where the signs are
present of some subsequent violent interference, this order is
uniform and invariable. It is not that all the members of the series
are invariably present, far from it; but in order of deposition the
relations of higher and lower are never interchanged. Every one of
the many different layers which have been distinguished by geologists
has a distinctive group of fossils. You may, if you please, suppose
that for each of these layers of the earth’s crust there was a new
creation of living creatures, wonderfully like at each successive
step, though wonderfully different at long intervals, as though they
were the work of an artist whose ideas moved but slowly; but for
such a supposition you have no authority; the conception has neither
simplicity nor grandeur; it does not even accord with the facts, since,
amid the general change of organic structures, we find the permanence
of a few; and while the groups of two successive layers have, each
of them, numerous distinctive forms, it is impossible to draw any
definite boundary-line between the groups themselves, which sometimes
intermingle with an inextricable interlacing on their confines. Nothing
comes out more clearly to the student of the rocks, than that the world
of to-day is the world of millions of years back; from one point of
view ever-changing, yet ever essentially the same; from another point
of view, out of the utmost regularity of alternation, never producing
the same thing, or presenting the same aspect twice. We think that
the stage has been essentially altered, because in the days of that
immeasurable past _we_ did not strut upon it. We are unable to fathom
the depth of our own insignificance, and are unwilling to believe in a
march of time, compared with which the span of our own lives seems so
contemptible. In the depths of the ocean the formation of chalk is said
to be going on at this very day. Probably there is no time known to the
geologist at which the formation of chalk has not been going on in the
depths of the ocean; but its older layers have been altered by chemical
and mechanical forces, by fire, by pressure, and by other means.
We know that chalk and limestone do not form in the open air. If we
find them piled up in enormous hills and mountains high above the level
of the sea, and far from its coasts, we know that they did not grow in
that position; that once their proud crests and ridges lay low in an
ocean bed. They could not have been formed on a sudden, or rapidly, or
by any other than the slow steps of infinitesimally small successive
accumulations: for we find them filled throughout with the evidences of
life, shells and sponges, and corals of exquisite beauty and delicacy,
generations after generations of which must have had time to build up
their beautiful fabrics. Many things may be hastened; you may quicken
the growth of many; but you can’t hurry a sponge. Every foot and inch
of a chalk cliff, of a limestone mountain, must have been formed
originally under water with almost incredible slowness. It must have
been raised up to meet the clouds of heaven since its formation in the
ocean-depth. Do you think that this can have been a rapid process?
Volcanic cones, it is true, are sometimes piled up by a sudden effort.
But with widespread platforms of solid rock the upheaving forces deal
more respectfully. An average elevation of a foot or two in a century,
is perhaps a high exceptional speed for such movements. But this rate
requires a thousand centuries for a hill only one or two thousand feet
high, to rise, not from the depths, but from the surface of the water.
If we had only a single formation to deal with instead of scores of
them; if we had a thickness of only one thousand feet of the earth’s
crust to consider, instead of scores of thousands, the proved antiquity
of the globe would be enormous. What is to be said, then, when we stand
face to face with what geologists have been pleased to call the new
red sandstone? This formation cannot be less than millions of years
old, although in relation to the Devonian limestone it is indisputably
new. Those deep red rocks, that with their fantastic profiles in so
many places fringe the southern border of Devon, must have been formed
since the limestone; for the simple reason, that in every part they are
full of pebbles or fragments of the limestone containing characteristic
fossils of the earlier formations. It will at least be granted that you
cannot break off a piece from a rock before the rock itself exists.
Prior, then, to the very beginning of the formation of these red
conglomerates, the limestone rock must have been formed; it must have
been heaved up above the level of the sea; fragments must have been
broken off from it, rolled into pebbles, triturated into sand. As the
breaking, and the rolling, and the grinding went on, so with equal
steps would the growth of the conglomerate proceed. But the workshop
and the work must still have been beneath the waters of the ocean, and
not till the whole work of formation was finished could the further
process be begun of raising the work above the level of the waves.
It is not uncommon to find fossils in the pebbles of a conglomerate
rock showing lines of a dislocating fracture filled with spar. The
fossil shell or coral once had an inhabitant. We must allow time
for its life and death. Its vacant tabernacle must then have become
filled with extraneous matter. This must have required time to harden
into rock. While that rock was still in the mass, some cause must
have operated to fracture it, and such causes are not of every-day
operation. After this, more time was needed to fill up the divisional
line with spar; more time to break off the fragment containing the
shell from the general mass of the rock; more time to roll it into a
pebble; more time to imbed it hard and fast in a conglomerate rock;
more time to raise the rock high out of the waters; and, lastly, one
more vast addition of time for the crumbling away of the conglomerate
formation, so as to expose the tall sea-cliff from which human hands
might gather this memorial relic of untold ages.
The same tale is told by the coal-measures. Dr. Dawson, of Montreal,
has drawn out the argument from the carboniferous formation[57] with
extraordinary force and a convincing plainness that leaves nothing to
be desired, for the benefit of any one who will read his great work on
Acadian geology. The formation of coal depends on sub-aërial growths,
affected by sub-aqueous action. The trees and plants, out of which
coal is formed, for the most part could not possibly have grown under
water. The mud, the sand, the stone which cover seams of coal, could
not have been laid over them without the agency of water to bring them
down, and spread them out in regular layers of stratification. When the
hollow bark of a tall tree is found erect upon its roots, with those
roots still permeating the clay from which they once drew nourishment,
it is evident that time must be allowed for the growth of the tree,
for the almost complete decay which left nothing of it but its bark
and roots, and for the slow accumulation of sediment which has encased
without overthrowing it. A complete alteration must have taken place
in the conditions of the ground in the interval between the time when
the tree began to grow, and the time when a length of seven or eight
feet of its upright stem was buried in mud. Layers, indeed, of sand and
mud may be spread out over small areas by storms and inundations with
comparative speed; but if above the sands we come to thicknesses of
limestone composed almost entirely of animal remains, such as those
of shells and fish, not only are we forced to admit a long period for
the successive generations of those creatures, but we are forced to
observe the products of the ocean lying actually above the products of
the dry land, as though, according to the old poetical extravagance,
the stag and doe had taken to the waters and the fishes been building
in the tree-tops. The conclusion is inevitable, that what was once dry
land, fruitful in vegetation, in process of time became a swamp, and
from the swamp became a sea. It will be a fresh surprise, but a fresh
evidence of time’s duration, if above the limestone we find more clay
with more plants buried in more mud, and over-topped by more limestone.
Bearing in mind the old supposition, that order and beauty and life
upon the globe are only six thousand years’ old, astonishment should
reach its climax when we find, as we do, that within the thickness of
only a few feet of the earth’s crust, the record that we have been
describing is repeated again and again and again; but beyond the
climax, a fresh and overpowering marvel awaits us, when, as at one spot
in British America, the record expands itself from a few feet into
sixteen thousand, showing conclusively by eighty successive bands of
coal that fourscore times at least, and perhaps many more, while that
thickness of the earth’s crust was forming, the waters gave place to
dry land, and in turn the dry land to the waters,--showing conclusively
that during all the period of these changes tall forests of graceful
trees abounded on the globe, along with exquisite ferns and curious
reptiles, and beetles and winged insects of great size and beauty;
while fish replenished the waters, along with an infinity of shells and
corals, and other inhabitants of the deep. Yet these sixteen thousand
feet, these eighty successive forests, these hundred and sixty changes,
comprise but a small fraction of the whole known succession of strata.
It is true that different strata not only may, but must have been
forming at one and the same time in different parts of the world.
But when one stratum has been formed out of the wreck of another, it
is self-evident that they cannot have been formed together. The same
thing is obvious in regard to any number of layers found lying in
undisturbed succession one above the other. They must have been formed
successively, the lowest first, the highest last. But one point about
them is far from obvious, namely, the length of the interval that may
have intervened between the end of one formation and the beginning of
another. The great African desert has been the great African desert as
far back as human histories extend; yet in times geologically recent
it lay beneath the waters of the ocean. Should it be again submerged
before any fertilizing agencies have covered it with signs of its
sub-aërial exposure, another layer of sand may be thrown down upon it,
containing new marine fossils, and no memorial be left to the future
geologist of the vast era during which its kindly influence was warming
the winds of Europe, and saving us from a glacial climate. The ground
you stand on is passing through such an interval. It was under the sea
once; doubtless it will be under the sea again in the future. Look
into that future; look into that past. Can you measure either of those
intervals in the years of common chronology? Yet all over the world the
succession of geological strata proclaims the recurrence over and over
again of such intervals; silent, indeed, as to positive evidence, but
widening the possible limits of time’s duration to the furthest stretch
of fancy.
All our great continents have been ever so many times, either in the
mass or piecemeal, under the waves of the ocean. Nothing hinders that
the bed of every great ocean should have been ever so many times turned
into dry land. This interchange is going on now in numberless regions
of sea and land. All the facts as we find them are such as they might
be expected to be had this interchange been going on, as no doubt it
has been, through an indefinite past. We are bound to allow millions
of years for the formation of the strata that have been already
examined. There may be depths below the lowest depths yet explored by
geologists; there have certainly been immense intervals which have left
no materials for the geologist to explore; and when all the profoundest
deep of stratification shall have been explored, we may still find that
the record of all these unnumbered millions of years is but, as it
were, the latest page of the volume--a page that may have been preceded
by a thousand others now almost irrevocably lost or become utterly
illegible. There is nothing to hinder the supposition that those
earlier pages, if they existed, were, amidst innumerable differences,
still in their general aspect very like the latest, as long or longer,
as full of the memorials of eventful circumstance, of constant change
dominated by and springing from the operation of unchanging laws. As
the time is absolutely incalculable which the theory of evolution
requires to account for the highest forms of life upon the earth, so
the time which all these considerations leave open for the work is
absolutely beyond calculation. The theory cannot ask for more than the
facts make it possible to offer.
We hear men sometimes dwell on an expression which they fancy to be
Scriptural, ‘that there should be time no longer[58];’ as if time by
any possibility could ever come to an end! It is a pity that they
should completely misinterpret the passage on which their opinion
fancies itself to be grounded. It is a still greater pity that they
should use the language of rational human beings, without being at the
pains to determine whether their words have any intelligible meaning:
for certainly to the human mind any beginning or end of time is wholly
inconceivable. Language itself will not bear with the conception,
unless it be consistent to speak of a _time_ when time was not, of a
_time_ when time will be no more.
There is a poem, and a sweet one, by the present Poet-Laureate,
in which the murmuring brook is made to speak the language of the
moralist, and to proclaim the transitory nature of all human affairs,
by a comparison between the short duration of man’s life and its own
unceasing current--
‘For men may come, and men may go,
But I flow on for ever.’
Such is the proud language of the murmuring brook. Yet the boast is
an untrue one; for if any conclusion in regard to the future can be
warranted from the facts of the past, none can be more sure than
that no particular brook will flow on for ever. Instead of a brook,
it may become a mighty river like the St. Lawrence; it may dash over
precipitous cliffs with a vaster fall and volume than Niagara; and,
after all, the slow inexorable changes of the earth’s crust will one
day make its flow impossible, and the channel of it shall know its
stream no more. Only the flow of time is unending, of time which does
nothing, but out of or without which nothing can be done,--of time,
replete with glorious wonders as far back as the knowledge or the
imagination of man can penetrate, through every age, through every
million of years that can be rescued from forgetfulness, bearing fresh
testimony, in the greatness and the endlessness of the work, to the
eternal power and wisdom of the Supreme Worker.
NOTE ON THE HYPOTHESIS OF SPONTANEOUS GENERATION.
Presuming that there is not a particle of evidence as yet established
in favour of the supposition known as the doctrine of _abiogenesis_,
it does not follow that no such evidence ever will, or ever can, be
forthcoming. The advancement of science is continually doing away with
harsh, abrupt outlines, and revealing the softest shades of transition
in the varied scenery of nature. Between organic and inorganic matter,
between the inert and the living mass, the line of separation has
been hitherto, to our minds, the hardest and sharpest of all. We have
indeed become so accustomed to this violation of the cosmos, this harsh
interruption to the continuous order of nature, and to the simplicity
of its general plan, that we are apt to be rather annoyed than pleased
with the first efforts made to prove them only imaginary. There is a
dignity about life which requires, it is thought, to be defended from
too close a proximity in character to the chemical solids and liquids
amongst which it makes its appearance, even though the life whose
dignity is thus maintained exhibit little more than the functions of a
stomach, or be presented in the somewhat dull animation of a chrysalis
and the torpor of a slug.