different type from their predecessors, are still the prevailing
forms. The Dinotherium, one of the greatest quadrupedal mammals that
ever lived, seems to have formed a connecting link in this middle age
between the Pachydermata and the Cetaceæ. Each ramus of the under
jaw, which in the larger specimens are fully four feet in length,
bore at the symphysis a great bent tusk turned downward, which
appears to have been employed as a pick-axe in uprooting the aquatic
plants and liliaceous roots on which the creature seems to have
lived. The head, which measured about three feet across--a breadth
sufficient, surely, to satisfy the demands of the most exacting
phrenologist--was provided with muscles of enormous strength,
arranged so as to give potent effect to the operations of this
strange tool. The hinder part of the skull not a little resembled
that of the Cetaceæ; while, from the form of the nasal bones, the
creature was evidently furnished with a trunk like the elephant. It
seems not improbable, therefore, that this bulkiest of mammaliferous
quadrupeds constituted, as I have said, a sort of uniting tie between
creatures still associated in the human mind, from the circumstances
of their massive proportions, as the greatest that swim the sea
or walk the land--the whale and the elephant The Mastodon, an
elephantoid animal, also furnished, like the elephant, with tusks
and trunk, but marked by certain peculiarities which constitute it
a different genus, seems in Europe to have been contemporary with
the Dinotherium; but in North America (the scene of its greatest
numerical development) it appears to belong to a later age. In
height it did not surpass the African elephant, but it considerably
exceeded it in length--a specimen which could not have stood above
twelve feet high indicating a length of about twenty-five feet: it
had what the elephants want--tusks fixed in its lower jaw, which the
males retained through life, but the females lost when young; its
limbs were proportionally shorter, but more massive, and its abdomen
more elongated and slim; its grinder teeth, too, some of which have
been known to weigh from seventeen to twenty pounds, had their cusps
elevated into great mammæ-like protuberances, to which the creature
owes its name, and wholly differ in their proportions and outline
from the grinders of the elephant. The much greater remoteness of the
mastodontic period in Europe than in America is a circumstance worthy
of notice, as it is one of many facts that seem to indicate a general
transposition of at least the later geologic ages on the opposite
sides of the Atlantic.
EUROPEAN AND ASIATIC DELUGES
--LOUIS FIGUIER
The Tertiary formations, in many parts of Europe of more or less
extent, are covered by an accumulation of heterogeneous deposits,
filling up the valleys, and composed of very various materials,
consisting mostly of fragments of the neighboring rocks. The erosions
which we remark at the bottoms of the hills, and which have greatly
enlarged already existing valleys; the mounds of gravel accumulated
at one point, and which is formed of rolled materials, that is
to say, of fragments of rocks worn smooth and round by continual
friction during a long period, in which they have been transported
from one point to another--all these signs indicate that these
denudations of the soil, these displacements and transports of very
heavy bodies to great distances, are due to the violent and sudden
action of large currents of water. An immense wave has been thrown
suddenly on the surface of the earth, making great ravages in its
passage, furrowing the earth and driving before it débris of all
sorts in its disorderly course.
To what cause are we to attribute these sudden and apparently
temporary invasions of the earth’s surface by rapid currents of
water? In all probability to the upheaval of some vast extent of dry
land, to the formation of some mountain or mountain range in the
neighborhood of the sea, or even in the bed of the sea itself. The
land, suddenly elevated by an upward movement of the terrestrial
crust, or by the formation of ridges and furrows at the surface, has,
by its reaction, violently agitated the waters, that is to say, the
more mobile portion of the globe. By this new impulse the waters have
been thrown with great violence over the earth, inundating the plains
and valleys, and for the moment covering the soil with their furious
waves, mingled with the earth, sand, and mud, of which the devastated
districts have been denuded by their abrupt invasion.
There have been, doubtless, during the epochs anterior to the
Quaternary period many deluges such as we are considering. Mountains
and chains of mountains were formed by upheaval of the crust into
ridges, where it was too elastic or too thick to be fractured. Each
of these subterranean commotions would be provocative of momentary
irruptions of the waves.
But the visible testimony to this phenomenon--the living proofs
of this denudation, of this tearing away of the soil--is found
nowhere so strikingly as in the beds superimposed, far and near,
upon the Tertiary formations, and which bear the geological name of
_diluvium_. This term was long employed to designate what is now
better known as the “bowlder” formation, a glacial deposit which is
abundant in Europe north of the 50th, and in America north of the
40th, parallel, and reappearing again in the Southern Hemisphere;
but altogether absent in tropical regions. It consists of sand and
clay, sometimes stratified, mixed with rounded and angular fragments
of rock, generally derived from the same district; and their origin
has generally been ascribed to a series of diluvial waves raised
by hurricanes, earthquakes, or the sudden upheaval of land from
the bed of the sea, which had swept over continents, carrying with
them vast masses of mud and heavy stones, and forcing these stones
over rocky surfaces so as to polish and impress them with furrows
and striæ. Other circumstances occurred, however, to establish a
connection between this formation and the glacial drift. The size and
number of the erratic blocks increase as we travel toward the Arctic
regions; some intimate association exists, therefore, between this
formation and the accumulations of ice and snow which characterize
the approaching glacial period.
There is very distinct evidence of two successive deluges in our
hemisphere during the Quaternary epoch. The two may be distinguished
as the _European Deluge_ and the _Asiatic_. The two European deluges
occurred prior to the appearance of man; the Asiatic deluge happened
after that event; and the human race, then in the early days of its
existence, certainly suffered from this cataclysm.
The first occurred in the north of Europe, where it was produced by
the upheaval of the mountains of Norway. Commencing in Scandinavia,
the wave spread and carried its ravages into those regions which
now constitute Sweden, Norway, European Russia, and the north of
Germany, sweeping before it all the loose soil on the surface, and
covering the whole of Scandinavia--all the plains and valleys of
Northern Europe--with a mantle of transported soil. As the regions
in the midst of which this great mountainous upheaval occurred--as
the seas surrounding these vast spaces were partly frozen and covered
with ice, from their elevation and neighborhood to the pole--the wave
which swept these countries carried along with it enormous masses of
ice.
The physical proof of this _deluge of the north of Europe_ exists
in the accumulation of unstratified deposits which covers all the
plains and low grounds of Northern Europe. On and in this deposit
are found numerous blocks which have received the characteristic
and significant name of erratic blocks, and which are frequently of
considerable size. These become more characteristic as we ascend to
higher latitudes, as in Norway, Sweden, and Denmark, the southern
borders of the Baltic, and in the British Islands generally, in all
of which countries deposits of marine fossil shells occur, which
prove the submergence of large areas of Scandinavia, of the British
Isles, and other regions during parts of the glacial period. Some of
these rocks, characterized as _erratic_, are of very considerable
volume; such, for instance, is the granite block which forms the
pedestal of the statue of Peter the Great at St. Petersburg. This
block was found in the interior of Russia, where the whole formation
is _Permian_, and its presence there can only be explained by
supposing it to have been transported by some vast iceberg, carried
by a diluvial current. This hypothesis alone enables us to account
for another block of granite, weighing about 340 tons, which was
found on the sandy plains in the north of Prussia, an immense model
of which was made for the Berlin Museum. The last of these erratic
blocks deposited in Germany covers the grave of King Gustavus
Adolphus, of Sweden, killed at the battle of Lutzen, in 1632. He was
interred beneath the rock. Another similar block has been raised in
Germany into a monument to the geologist Leopold von Buch.
These erratic blocks, which are met with in the plains of Russia,
Poland, and Prussia, and in the eastern parts of England, are
composed of rocks entirely foreign to the region where they are
found. They belong to the primary rocks of Norway; they have been
transported to their present sites, protected by a covering of ice,
by the waters of the northern deluge.
The second European deluge is supposed to have been the result of
the formation and upheaval of the Alps. It has filled with débris
and transported material the valleys of France, Germany, and Italy
over a circumference which has the Alps for its centre. The proofs
of a great convulsion at a comparatively recent geological date are
numerous. The Alps may be from eighty to one hundred miles across,
and the probabilities are that their existence is due, as Sir Charles
Lyell supposes, to a succession of unequal movements of upheaval and
subsidence; that the Alpine region had been exposed for countless
ages to the action of rain and rivers, and that the larger valleys
were of pre-glacial times, is highly probable. In the eastern part
of the chain some of the Primary fossiliferous rocks, as well as
Oolitic and Cretaceous rocks, and even Tertiary deposits, are
observable; but in the central Alps these disappear, and more recent
rocks, in some places even Eocene strata, graduate into metamorphic
rocks, in which Oolitic, Cretaceous, and Eocene strata have been
altered into granular marble, gneiss, and other metamorphic schists;
showing that eruptions continued after the deposit of the Middle
Eocene formations. Again, in the Swiss and Savoy Alps, Oolitic and
Cretaceous formations have been elevated to the height of 12,000
feet, and Eocene strata 10,000 feet above the level of the sea; while
in the Rothal, in the Bernese Alps, occurs a mass of gneiss 1,000
feet thick between two strata containing Oolitic fossils.
Besides these proofs of recent upheaval, we can trace effects of two
different kinds, resulting from the powerful action of masses of
water violently displaced by this gigantic upheaval. At first broad
tracks have been hollowed out by the diluvial waves, which have, at
these points, formed deep valleys. Afterward these valleys have been
filled up by materials derived from the mountain and transported
into the valley, these materials consisting of rounded pebbles,
argillaceous and sandy mud, generally calcareous and ferriferous.
This double effect is exhibited, with more or less distinctness, in
all the great valleys of the centre and south of France. The valley
of the Garonne is, in respect to these phenomena, classic ground, as
it were.
The small valleys, tributary to the principal valley, would appear to
have been excavated secondarily, partly out of diluvial deposits, and
their alluvium, essentially earthy, has been formed at the expense of
the Tertiary formation, and even of the diluvium itself. Among other
celebrated sites, the diluvial formation is largely developed in
Sicily. The ancient temple of the Parthenon at Athens is built on an
eminence formed of diluvial earth.
In the valley of the Rhine, in Alsace, and in many isolated parts of
Europe, a particular sort of _diluvium_ forms thick beds; it consists
of a yellowish-gray mud, composed of argillaceous matter mixed with
carbonate of lime, quartzose and micaceous sand, and oxide of iron.
This mud, termed by geologists _loess_, attains in some places
considerable thickness. It is recognizable in the neighborhood of
Paris. It rises a little both on the right and left, above the base
of the mountains of the Black Forest and of the Vosges; and forms
thick beds on the banks of the Rhine.
The fossils contained in diluvial deposits consist, generally, of
terrestrial, lacustrine, or fluviatile shells, for the most part
belonging to species still living. In parts of the valley of the
Rhine, between Bingen and Basle, the fluviatile loam or _loess_,
now under consideration, is seen forming hills several hundred feet
thick, and containing, here and there, throughout that thickness,
land and fresh-water shells; from which it seems necessary to
suppose, according to Lyell, first, a time when the _loess_ was
slowly accumulated, then a later period, when large portions of it
were removed--and followed by movements of oscillation, consisting,
first, of a general depression, and then of a gradual re-elevation of
the land.
The Asiatic deluge--of which sacred history has transmitted to us
the few particulars we know--was the result of the upheaval of a
part of the long chain of mountains which are a prolongation of
the Caucasus. The earth opening by one of the fissures made in its
crust, in course of cooling, an eruption of volcanic matter escaped
through the enormous crater so produced. Volumes of watery vapor or
steam accompanied the lava discharged from the interior of the globe,
which, being first dissipated in clouds and afterward condensing,
descended in torrents of rain, and the plains were drowned with the
volcanic mud. The inundation of the plains over an extensive radius
was the immediate effect of this upheaval, and the formation of the
volcanic cone of Mount Ararat, with the vast plateau on which it
rests, altogether 17,323 feet above the sea, the permanent result.
The event is graphically detailed in the seventh chapter of Genesis.
All the particulars of the Biblical narrative here recited are only
to be explained by the volcanic and muddy eruption which preceded the
formation of Mount Ararat. The waters which produced the inundation
of these countries proceeded from a volcanic eruption accompanied
by enormous volumes of vapor, which in due course became condensed
and descended on the earth, inundating the extensive plains which
now stretch away from the foot of Ararat. The expression, “the
earth,” or “all the earth,” as it is translated in the Vulgate, which
might be implied to mean the entire globe, is explained by Marcel
de Serres, in a learned book entitled _La Cosmogonie de Moïse_,
and other philologists, as being an inaccurate translation. He has
proved that the Hebrew word _haarets_, incorrectly translated “all
the earth,” is often used in the sense of _region_ or _country_, and
that, in this instance, Moses used it to express only the part of
the globe which was then peopled, and not its entire surface. In the
same manner “_the mountains_” (rendered “_all the mountains_” in the
Vulgate) only implies all the mountains known to Moses.
Of this deluge many races besides the Jews have preserved a
tradition. Moses dates it from 1,500 to 1,800 years before the epoch
in which he wrote. Berosus, the Chaldean historian, who wrote at
Babylon in the time of Alexander, speaks of a universal deluge, the
date of which he places immediately before the reign of Belus, the
father of Ninus.
The _Vedas_, or sacred books of the Hindus, supposed to have been
composed about the same time as Genesis, that is, about 3,300 years
ago, make out that the deluge occurred 1,500 years before their time.
The _Guebers_ speak of the same event as having occurred about the
same date.
Confucius, the celebrated Chinese philosopher and lawgiver, born
toward the year 551 before Christ, begins his history of China by
speaking of the Emperor named Jas, whom he represents as making the
waters flow back, which, being _raised to the heavens_, washed the
feet of the highest mountains, covered the less elevated hills, and
inundated the plains. Thus the Biblical deluge is confirmed in many
respects; but it was local, like all phenomena of the kind, and was
the result of the upheaval of the mountains of western Asia.
GLACIERS
--LOUIS AGASSIZ
The long summer was over. For ages a tropical climate had prevailed
over a great part of the earth, and animals whose home is now beneath
the equator roamed over the world from the far south to the very
borders of the Arctics. The gigantic quadrupeds, the mastodons,
elephants, tigers, lions, hyenas, bears, whose remains are found in
Europe from its southern promontories to the northernmost limits of
Siberia and Scandinavia, and in America from the Southern States
to Greenland and the Melville Islands, may indeed be said to have
possessed the earth in those days. But their reign was over. A
sudden intense winter, that was also to last for ages, fell upon
our globe; it spread over the very countries where these tropical
animals had their homes, and so suddenly did it come upon them that
they were embalmed beneath masses of snow and ice, without time even
for the decay which follows death. The elephant was by no means a
solitary specimen; upon further investigation it was found that the
disinterment of these large tropical animals in Northern Russia and
Asia was no unusual occurrence. Indeed, their frequent discoveries
of this kind had given rise among the ignorant inhabitants to the
singular superstition that gigantic moles lived under the earth which
crumbled away and turned to dust as soon as they came to the upper
air. This tradition, no doubt, arose from the fact that, when in
digging they came upon the bodies of these animals, they often found
them perfectly preserved under the frozen ground, but the moment
they were exposed to heat and light they decayed and fell to pieces
at once. Admiral Wrangell, whose Arctic explorations have been so
valuable to science, tells us that the remains of these animals are
heaped up in such quantities in certain parts of Siberia that he and
his men climbed over ridges and mounds consisting entirely of the
bones of elephants, rhinoceroses, etc.
We have as yet no clew to the source of this great and sudden change
of climate. Various suggestions have been made, among others that
formerly the inclination of the earth’s axis was greater, or that
the submersion of the continents under water might have produced
a decided increase of cold; but none of these explanations is
satisfactory, and science has yet to find any cause which accounts
for all the phenomena connected with it. It seems, however,
unquestionable that, since the opening of the Tertiary age, a cosmic
summer and winter have succeeded each other, during which a tropical
heat and an Arctic cold have alternately prevailed over a great
portion of the present temperate zone. In the so-called drift (a
superficial deposit subsequent to the Tertiaries) there are found far
to the south of their present abode the remains of animals whose
home now is in the Arctics or the coldest parts of the Temperate
Zones. Among them are the musk-ox, the reindeer, the walrus, the
seal, and many kinds of shells characteristic of the Arctic regions.
The northernmost part of Norway and Sweden is at this day the
southern limit of the reindeer in Europe; but their fossil remains
are found in large quantities in the drift about the neighborhood of
Paris, and they have been traced even to the foot of the Pyrenees,
where their presence would, of course, indicate a climate similar to
the one now prevailing in Northern Scandinavia. Side by side with
the remains of the reindeer are found those of the European marmot,
whose present home is in the mountains, about six thousand feet
above the level of the sea. The occurrence of these animals in the
superficial deposits of the plains of Central Europe, one of which
is now confined to the high north and the other to mountain heights,
certainly indicates an entire change of climatic conditions since
the time of their existence. European shells now confined to the
Northern Ocean are found as fossils in Italy, showing that, while
the present Arctic climate prevailed in the Temperate Zone, that of
the Temperate Zone extended much further south to the regions we now
call sub-tropical. In America there is abundant evidence of the same
kind; throughout the recent marine deposits of the Temperate Zone,
covering the low lands above tide water on this Continent, are found
fossil shells whose present home is on the shores of Greenland. It is
not only in the Northern Hemisphere that these remains occur, but in
Africa and in South America, wherever there has been an opportunity
for investigation, the drift is found to contain the traces of
animals whose presence indicates a climate many degrees colder than
that now prevailing there.
But these organic remains are not the only evidence of the geological
winter. There are a number of phenomena indicating that during
this period two vast caps of ice stretched from the northern pole
southward and from the southern pole northward, extending in each
case far toward the equator, and that ice fields, such as now spread
over the Arctics, covered a great part of the Temperate Zones, while
the line of perpetual ice and snow in the tropical mountain ranges
descended far below its present limits.
The first essential condition for the formation of glaciers in
mountain ranges is the shape of their valleys. Glaciers are by no
means in proportion to the height and extent of mountains. There
are many mountain chains as high or higher than the Alps which can
boast of but few and small glaciers, if, indeed, they have any. In
the Andes, the Rocky Mountains, the Pyrenees, the Caucasus, the few
glaciers remaining from the great ice period are insignificant in
size. The volcanic, cone-like shape of the Andes gives, indeed, but
little chance for the formation of glaciers, though their summits
are capped with snow. The glaciers of the Rocky Mountains have been
little explored, but it is known that they are by no means extensive.
In the Pyrenees there is but one great glacier, though the height
of these mountains is such that, were the shape of their valleys
favorable to the accumulation of snow, they might present beautiful
glaciers. In the Tyrol, on the contrary, as well as in Norway and
Sweden, we find glaciers as fine as those of Switzerland in mountain
ranges much lower than either of the above-mentioned chains. But they
are of diversified forms, and have valleys widening upward on the
slope of long crests. The glaciers on the Caucasus are very small in
proportion to the height of the range; but on the northern side of
the Himalayas there are large and beautiful ones, while the southern
slope is almost destitute of them. Spitzbergen and Greenland are
famous for their extensive glaciers, coming down to the seashore,
where huge masses of ice, many hundred feet in thickness, break off
and float away into the ocean as icebergs.
At the Aletsch in Switzerland, where a little lake lies in a deep cup
between the mountains, with the glacier coming down to its brink, we
have these Arctic phenomena on a small scale; a miniature iceberg
may often be seen to break off from the edge of the larger mass and
float out upon the surface of the water. Icebergs were first traced
back to their true origin by the nature of the land ice of which they
were always composed, and which is quite distinct in structure and
consistency from the marine ice produced by frozen sea water, and
called “ice flow” by the Arctic explorers, as well as from the pond
or river ice, resulting from the simple congelation of fresh water,
the laminated structure of which is in striking contrast to the
granular structure of glacier ice.