Direction of the Forces that raised the Continents—Proportion of Land
and Water—Size of the Continents and Islands—Outline of the Land—
Extent of Coasts, and proportion they bear to the Areas of the
Continents—Elevation of the Continents—Forms of Mountains—Forms of
Rocks—Connection between Physical Geography of Countries and their
Geological Structure—Contemporaneous Upheaval of parallel Mountain
Chains—Parallelism of Mineral Veins or Fissures—Mr. Hopkins’s Theory
of Fissures—Parallel Chains similar in Structure—Interruptions in
Continents and Mountain Chains—Form of the Great Continent—The High
Lands of the Great Continent—The Atlas, Spanish, French, and German
Mountains—The Alps, Balkan, and Apennines—Glaciers—Geological Notice.
AT the end of the tertiary period the earth was much in the same state
as it is at present with regard to the distribution of land and water.
The preponderance of land in the northern hemisphere indicates a
prodigious accumulation of internal energy under these latitudes at a
very remote geological period. The forces that raised the two great
continents above the deep, when viewed on a wide scale, must evidently
have acted at right angles to one another, nearly parallel to the
equator in the old continent, and in the direction of the meridian in
the new; yet the structure of the opposite coasts of the Atlantic points
at some connection between the two.
The mountains, from their rude and shattered condition, bear testimony
to repeated violent convulsions similar to modern earthquakes; while the
high table-lands, and that succession of terraces by which the
continents sink down from their mountain-ranges to the plains, to the
ocean, and even below it, show also that the land must have been heaved
up occasionally by slow and gentle pressure, such as appears now to be
gradually elevating the coast of Scandinavia and many other parts of the
earth. The periods in which these majestic operations were effected must
have been incalculable, since the dry land occupies an area of nearly
38,000,000 of square miles.
The ocean covers nearly three-fourths of the surface of the globe, but
the distribution is very unequal, whether it be considered with regard
to the northern and southern hemispheres, or the eastern and western.
Independently of Victoria Land, whose extent is unknown, the quantity of
land in the northern hemisphere is three times greater than in the
southern. In the latter it occupies only one-sixteenth of the space
between the Antarctic Circle and the thirtieth parallel of south
latitude, while between the corresponding parallels in the northern
hemisphere the extent of land and water is nearly equal. If the globe be
divided into two hemispheres by a meridian passing through the island of
Teneriffe, the land will be found to predominate greatly on the eastern
side of that line, and the water on the western. In consequence of the
very unequal arrangement of the solid and liquid portions of the surface
of the earth, England is nearly in the centre of the greatest mass of
land, and its antipode, the island of New Zealand, is in the centre of
the greatest mass of water; so that a person raised above Falmouth,
which is almost the central point, till he could perceive a complete
hemisphere, would see the greatest possible expanse of land, while, were
he elevated to the same height above New Zealand, he would see the
greatest possible extent of ocean. In fact, only one twenty-seventh of
the land has land directly opposite to it in the opposite hemisphere,
and under the equator five-sixths of the circumference of the globe is
water. It must, however, be observed that there is still an unexplored
region within the Antarctic Circle more than twice the size of Europe,
and of the north polar basin we know nothing. With regard to the land
alone, the great continent has an area of about 24,000,000 square miles,
while the extent of America is 11,000,000, and that of Australia with
its islands scarcely 3,000,000. Africa is more than three times the size
of Europe, and Asia is more than four times as large. The extent of the
continents is twenty-three times greater than that of all the islands
taken together.[15]
Of the polar lands little is known. Greenland probably is part of a
continent, the domain of perpetual snow; and the recent discovery of so
extensive a mass of high volcanic land near the south pole is an
important event in the history of physical science, though the stern
severity of the climate must for ever render it unfit for the abode of
animated beings, or even for the support of vegetable life. It seems to
form a counterpoise to the preponderance of dry land in the northern
hemisphere. There is something sublime in the contemplation of these
lofty and unapproachable regions—the awful realm of ever-during ice and
perpetual fire, whose year consists of one day and one night. The
strange and terrible symmetry in the nature of the lands within the
polar circles, whose limits are to us a blank, where the antagonist
principles of cold and heat meet in their utmost intensity, fills the
mind with that awe which arises from the idea of the unknown and the
indefinite.
The tendency of the land to assume a peninsular form is very remarkable,
and it is still more so that almost all the peninsulas tend to the
south—circumstances that depend on some unknown cause which seems to
have acted very extensively. The continents of South America, Africa,
and Greenland, are peninsulas on a gigantic scale, all tending to the
south; the Asiatic peninsula of India, the Indo-Chinese peninsula, those
of Corea, Kamtchatka, of Florida, California, and Aliaska, in North
America, as well as the European peninsulas of Norway and Sweden, Spain
and Portugal, Italy and Greece, take the same direction. All the latter
have a rounded form except Italy, whereas most of the others terminate
sharply, especially the continents of South America and Africa, India,
and Greenland, which have the pointed form of wedges; while some are
long and narrow, as California, Aliaska, and Malacca. Many of the
peninsulas have an island or group of islands at their extremity, as
South America, which terminates with the group of Tierra del Fuego:
India has Ceylon; Malacca has Sumatra and Banca; the southern extremity
of New Holland ends in Van Dieman’s Land; a chain of islands run from
the end of the peninsula of Aliaska; Greenland has a group of islands at
its extremity; and Sicily lies close to the termination of Italy. It has
been observed as another peculiarity in the structure of peninsulas that
they generally terminate boldly, in bluffs, promontories, or mountains,
which are often the last portions of the continental chains. South
America terminates in Cape Horn, a high promontory, which is the visible
termination of the Andes; Africa with the Cape of Good Hope; India with
Cape Comorin, the last of the Ghauts; New Holland ends with South-East
Cape in Van Dieman’s Land; and Greenland’s farthest point is the
elevated bluff of Cape Farewell.[16]
There is a strong analogy between South America and Africa in form and
the unbroken mass which their surface presents, while North America
resembles Europe, in being much indented by inland seas, gulfs, and
bays. Eastern Asia is evidently continued in a subaqueous continent from
the Indian Ocean across the Pacific nearly to the west coast of America,
of which New Holland, the Indian Archipelago, the islands of the Asiatic
coast and of Oceania, are the great table-lands and summits of its
mountain-chains. With the exception of a vast peninsula in Siberia,
between the mouths of the rivers Yenesei and Khatanga and the unknown
regions of Greenland, the two great continents terminate in a very
broken line to the north; and as they sink beneath the Icy Ocean, the
tops of their high lands and mountains rise above the waves and stud the
coast with innumerable snow-clad rocks and islands. The 70th parallel is
the average latitude of these northern shores, which have a great
similarity on each side of Behring’s Straits in form, direction, and in
the adjacent islands.
The peninsular form of the continents adds greatly to the extent of
their coasts, of such importance to civilization and commerce. All the
shores of Europe are deeply indented and penetrated by the Atlantic
Ocean, which has formed a number of inland seas of great magnitude, so
that it has a greater line of maritime coast, compared with its size,
than any other quarter of the world. The extent of coast from the
Straits of Waigatz, in the Polar Ocean, to the Strait of Caffa, at the
entrance of the Sea of Azoff, is about 17,000 miles. The coast of Asia
has been much worn by currents, and possibly also by the action of the
ocean occasioned by the rotation of the earth from west to east. On the
south and east especially it is indented by large seas, bays, and gulfs;
and the eastern shores are rugged and encompassed by chains of islands
which render navigation dangerous. Its maritime coast is about 33,000
miles in length.
The coast of Africa, 16,000 miles long, is very entire, except perhaps
at the Gulf of Guinea and in the Mediterranean. The shores of North
America have probably been much altered by the equatorial current and
the Gulf-stream. There is little doubt that these currents, combined
with volcanic action, have hollowed out the Gulf of Mexico, and
separated the Antilles and Bahama Islands from the continent. The coast
is less broken on the west, but in the Icy Ocean there is a labyrinth of
gulfs, bays, and creeks. The shores of South America on both sides are
very entire, except towards Southern Chile and Cape Horn, where the
tremendous surge and currents of the ocean in those high latitudes have
eaten into the mountains, and produced endless sounds and fiords which
run far into the land. The whole continent of America has a sea-coast of
31,000 miles. Thus, it appears that the ratio of the number of linear
miles in the coast-line to the number of square miles in the extent of
surface, in each of these great portions of the globe, is 164 for
Europe, 376 for Asia, 530 for Africa, and 359 for America. Hence, the
proportion is most favourable to Europe, with regard to civilization and
commerce; America comes next, then Asia, and last of all Africa, which
has every natural obstacle to contend with, from the extent and nature
of its coasts, the desert character of the country, and the insalubrity
of its climate, on the Atlantic coast at least.
The continents had been raised from the deep by a powerful effort of the
internal forces acting under widely-extended regions, and the stratified
crust of the earth either remained level, rose in undulations, or sank
into cavities, according to its intensity. Some thinner portion of the
earth’s surface, giving way to the internal forces, had been rent into
deep fissures, and the mountain masses had been raised by violent
concussions, perceptible in the convulsed state of their strata. The
centres of maximum energy are marked by the pyrogenous rocks, which
generally form the nucleus or axis of the mountain masses, on whose
flanks the stratified rocks are tilted at all angles to the horizon,
whence, declining on every side, they sink to various depths, or stretch
to various distances in the plains. Enormous as the mountain-chains and
table-lands are, and prodigious as the forces that elevated them, they
bear a very small proportion to the mass of the level continents and to
the vast power which raised them even to their inferior altitude. Both
the high and the low lands had been elevated at successive periods; some
of the very highest mountain-chains are but of recent geological date,
and some chains that are now far inland once stood up as islands above
the ocean, while marine strata filled their cavities and formed round
their bases. The influence of mountain-chains on the extent and form of
the continents is beyond a doubt.
Notwithstanding the various circumstances of their elevation, there is
everywhere a certain regularity of form in mountain masses, however
unsymmetrical they may appear at first, and rocks of the same kind have
identical characters in every quarter of the globe. Plants and animals
vary with climate, but a granite mountain has the same peculiarities in
the southern as in the northern hemisphere—at the equator as near the
poles. Single mountains, insulated on plains, are rare, except where
they are volcanic; they generally appear in groups intersected by
valleys in every direction, and more frequently in extensive chains
symmetrically arranged in a series of parallel ridges, separated by
narrow longitudinal valleys, the highest and most rugged of which occupy
the centre: when the chain is broad and of the first order in point of
magnitude, peak after peak arises in endless succession. The lateral
ridges and valleys are constantly of less elevation, and are less bold,
in proportion to their distance from the central mass, till at last the
most remote ridges sink down into gentle undulations. Extensive and
lofty branches diverge from the principal chains at various angles, and
stretch far into the plains. They are often as high as the chains from
which they spring, and it happens not unfrequently that these branches
are united by transverse ridges, so that the country is often
widely-covered by a net-work of mountains, and, at the point where these
offsets diverge, there is frequently a knot of mountains spreading over
hundreds of square miles.
One side of a mountain range is usually more precipitous than the other,
but there is nothing in which the imagination misleads the judgment more
than in estimating the steepness of a declivity. In the whole range of
the Alps there is not a single rock which has 1600 feet of perpendicular
height, or a vertical slope of 90°. The declivity of Mont Blanc towards
the Allée Blanche, precipitous as it seems, does not amount to 45°; and
the mean inclination of the peak of Teneriffe, according to Baron
Humboldt, is only 12° 30ʹ. The Silla of Caraccas, which rises
precipitously from the Caribbean Sea, at an angle of 53° 28ʹ, to the
height of between 6000 and 7000 feet, is a majestic instance of perhaps
the nearest approach to perpendicularity of any great height yet known.
The circumstances of elevation are not the only causes of that variety
observed in the summits of mountains. A difference in the composition
and internal structure of a rock has a great influence upon its general
form, and on the degree and manner in which it is worn by the weather.
Thus dolomite assumes generally the form of peaks like saw-teeth;
crystalline schists assume the form of needles, as in the Alps; slates
and quartziferous schists take the form of triangular pyramids;
calcareous rocks a rounded shape; serpentine and trachyte are often
twisted and crumpled; phonolites assume a pyramidal form; dark walls
like those in Greenland are of trap and basalt; and volcanoes are
indicated by blunt cones and craters. Thus, the mountain-peaks often
indicate by their form their geological nature.
Viewing things on a broad scale, it appears that there is also a very
striking connection between the physical geography or external aspect of
different countries and their geological structure. By a minute
comparison of the different parts of the land, M. Boué has shown that a
critical similarity of outward forms, while indicating similarity in the
producing causes, must also, to a large extent, indicate identity of
structure, and therefore from the external appearance of an unexplored
country its geological structure may be inferred, at least to a certain
extent. This he illustrates by pointing out a correspondence, even in
their most minute details, between the leading features of Asia and
Europe, and the identity of their geological structure. It has been
justly observed, that when the windings of our continents and seas are
narrowly examined, and the more essential peculiarities of their
contours contemplated, it is evident that Nature has not wrought after
an indefinite number of types or models, but that, on the contrary, her
fundamental types are very few, and derived from the action of definite
constructive forces on a primary base.[17] The whole of our land and
sea, in fact, may be decomposed into a less or greater number of masses,
either exhibiting all these fundamental forms or merely a portion of
them.[18] The peninsular structure of the continents with their
accompanying islands is a striking illustration of the truth of this
remark, and many more might be adduced. It follows, as a consequence of
that law in Nature’s operations, that analogy of form and contour throws
the greatest light on the constitution of countries far removed from
each other. Even the picturesque descriptions of a traveller often
afford information of which he may be little aware.
The determination of the contemporaneous upheaval of parallel
mountain-chains, by a comparison of the ages of the inclined and
horizontal strata resting on them, is one of the highest steps of
generalization which has been attempted by geologists. It was first
observed by the miners of the Freyberg school, and established as a law
by Werner, that veins of the same nature in mines occur in parallel
fissures opened at the same time, and probably filled with metal, also
simultaneously, at a subsequent period; and that fissures differing in
direction differ also in age. As these veins and fissures are rents
through the solid strata, often of unfathomable depth and immense
length, there is the strongest analogy between them and those enormous
fissures in the solid mass of the globe through which the
mountain-chains have been heaved up. Were the analogy perfect, it ought
to follow that parallel mountain-chains have been raised simultaneously,
that is, by forces acting during the same geological periods. By a
careful examination of the relative ages of the strata resting on the
flanks of many of the mountain systems, M. Elie de Beaumont has shown,
if not proved, that all strata elevated simultaneously assume a parallel
direction, or, that parallel strata are contemporaneous. Should this be
confirmed, parallel chains in the most distant regions will no longer be
regarded as insulated masses. They will indicate the course of enormous
fissures that have simultaneously rent the solid globe and passed
through the bed of the ocean from continent to continent, from island to
island. M. Von Buch has found that four systems of mountains in Germany
accord with this theory, and Mr. Sedgwick has observed the same in the
Westmoreland system of mountains, believed to be the most ancient of
which the globe can now furnish any traces. This theory of elevation of
mountain-chains, which originated with M. Elie de Beaumont, has already
led to the discovery of twelve different periods of fracture and
elevation in the European continent alone.
Mr. Hopkins, of Cambridge, has taken a purely mathematical view of the
subject, and has proved that, when an internal expansive force acts
upwards upon a single point in the earth’s crust, the splits or cracks
must all diverge from that point like radii in a circle, which is
exactly the case in many volcanic districts; that when the expansive
force acts uniformly from below on a wide surface or area, it tends to
stretch the surface, so that it would split or crack where the tension
is greatest, that is, either in the direction of the length or breadth;
and if the area yields in more places than one, he found that the
fissures would necessarily be parallel to one another, which agrees with
the law of arrangement of veins in mines. These results are greatly
modified by the shape of the area, but the modification is according to
a fixed law, which, instead of interfering with that of the parallelism
of the fissures, actually arises from the same action which produces it.
This investigation agrees in all its details with the fractures in the
districts in England to which they were applied, so that theory comes to
the aid of observation in this still unsettled question.[19]
It seems to bear on the subject, that parallel mountain-chains are
similar in geological age, even when separated by seas. For instance,
the mountains of Sweden and Finland are of the same structure, though
the Gulf of Bothnia is between them; those of Cornwall, Brittany, and
the north-west of Spain are similar; the Atlas and the Spanish
mountains, the chains in California and those on the adjacent coast of
America, and, lastly, those of New Guinea and the north-east of
Australia, furnish examples. The same correspondence in geological epoch
prevails in chains that are not parallel, but that are convergent from
the form of the earth. This observation is also extensively exemplified
in those that run east and west, as the Alps, the Balkan, Taurus,
Paropamisus with its prolongation, the Hindoo Coosh, the Himalaya, and
in America the mountains of Parima and the great chain of Venezuela.
Continents and mountain-chains are often interrupted by posterior
geological changes, such as clefts and cavities formed by erosion, as
evidently appears from the correspondence of the strata. The chalk
cliffs on the opposite sides of the British Channel show that Britain
once formed part of the continent; the formation of the Orkney Islands
and Ireland is the same with that of the Highlands of Scotland; the
formation is the same on each side of the Straits of Gibraltar; that of
Turkey in Europe passes into Asia Minor, the Crimea into the Caucasus, a
volcanic region bounds the Straits of Babelmandel, and Behring’s Straits
divide the ancient strata of a similar age. This is particularly the
case with coast islands.[20]
Immediately connected with the mountains are the high table-lands which
form so conspicuous a feature in the Asiatic and American continents.
These perpetual storehouses of the waters send their streams to refresh
the plains, and to afford a highway between the nations. Table-lands of
less elevation, sinking in terraces of lower and lower level, constitute
the links between the high ground and the low, the mountains and the
plains, and thus maintain the continuity of the land. They frequently
are of the richest soil, and enjoy the most genial climate, affording a
delightful and picturesque abode to man, though the plains are his
principal dwelling. Sloping imperceptibly from the base of the inferior
table-lands, or from the last undulations of the mountains, to the
ocean, they carry off the superfluous waters. Fruitfulness and sterility
vary their aspect: immense tracts of the richest soil are favoured by
climate, and hardly require culture; a greater portion is only rendered
productive by hard labour, compelling man to fulfil his destiny; while
vast regions are doomed to perpetual barrenness, never gladdened by a
shower.
The form of the great continent has been determined by an immense zone
of mountains and table-lands, lying between the 30th and 40th or 45th
parallels of north latitude, which stretches across it from W.S.W. to
E.N.E., from the coasts of Barbary and Portugal, on the Atlantic Ocean,
to the farthest extremity of Asia, at Behring’s Straits, in the North
Pacific. North of this lies a vast plain, extending almost from the
Pyrenees to the utmost parts of Asia, the greater portion of which is a
dead level, or low undulations, uninterrupted except by the Scandinavian
and British system on the north, and the Ural chain, which is of small
elevation. The low lands south of the mountainous zone are much indented
by the ocean, and of the most diversified aspect. By much the greater
part of the flat country lying between the China Sea and the river Indus
is of the most exuberant fertility, while that between the Persian Gulf
and the foot of the Atlas is, with some happy exceptions, one of the
most desolate tracts on the earth. The southern lowlands, too, are
broken by a few mountain systems of considerable extent and height.
The Atlas and Spanish mountains form the western extremity of that great
zone of high lands that girds the old continent almost throughout its
extent: these two mountain systems were certainly at one time united,
and from their geological formation, and also the parallelism of their
mountain-chains, they must have been elevated by forces acting in the
same direction; now, indeed, the Strait of Gibraltar, a sea-filled chasm
960 fathoms deep, divides them.[21]
A very elevated and continuous mountain region extends in a broad belt
along the north-west of Africa, from the promontory of Gher, on the
Atlantic, to the Gulf of Sidra, in the Mediterranean, enclosing all the
high lands of Morocco, Algiers, and Tunis. It is bounded by the Atlantic
and Mediterranean, and insulated from the rest of Africa by the desert
of Sahara.
This mountain system consists of three parts. The chain of the Greater
Atlas, which is farthest inland, extends from Cape Gher, on the
Atlantic, to the Lesser Syrtis; and, in Morocco, forms a knot of
mountains 15,000 feet high, covered with perpetual snow.
The Lesser Atlas begins at Cape Spartel (the ancient Cape Cotes)
opposite to Gibraltar, and keeps parallel to the Mediterranean till it
attains the Gharian range in Tripoli, the last and lowest of the Little
Atlas, which runs due east in a uniformly diminishing line till it
vanishes in the plain of the Great Syrtis. That long, rugged, but lower
chain of parallel ridges and groups which forms the bold coasts of the
Straits of Gibraltar and the Mediterranean, is only a portion of the
Lesser Atlas, which rises above it majestically, covered with snow. The
flanks of the mountains are generally clothed with forests, but their
summit is one uninterrupted line of bare inaccessible rocks, and they
are rent by fissures frequently not more than a few feet wide—a peculiar
feature of the whole system.
The Middle Atlas, lying between the two great chains, consists of a
table-land, rich in valleys and rivers, which rises in successive
terraces to the foot of the Greater Atlas, separated by ridges of hills
parallel to it. This wide and extensive region has a delightful climate,
abounds in magnificent forests, and the valleys are full of vitality.
The crest of the Atlas is of granite and crystalline strata; their
flanks and lower ranges are sandstone and limestone, on which the
tertiary strata rest.
The Spanish peninsula consists chiefly of a table-land traversed by
parallel ranges of mountains, and is surrounded by the sea, except where
it is separated from France by the Pyrenees, which extend from the
Mediterranean to the Bay of Biscay, but are continued by the Cantabrian
chain to Cape Finisterre on the Atlantic.
The Pyrenean chain is of moderate height at its extremities, but its
summit maintains a waving line, whose mean altitude is 7990 feet; it
rises to a greater height on the east; its highest point is the Malahite
or Nethou, 11,170 feet above the sea. The snow lies deep on these
mountains during the greater part of the year, and is perpetual on the
highest parts; but the glaciers, which are chiefly on the northern side,
are neither so numerous nor so large as in the Alps.
The greatest breadth of this range is about 60 miles, and its length
270. It is so steep on the French side, so rugged and so notched, that
from the plains below its summits look like the teeth of a saw, whence
the term Sierra has been appropriated to mountains of this form. On the
Spanish side, gigantic sloping offsets, separated by deep precipitous
valleys, extend to the banks of the Ebro. All the Spanish mountains are
torn by deep crevices, the beds of torrents and rivers.
The interior of Spain is a table-land with an area of 93,000 square
miles, nearly equal to half of the peninsula. It dips to the Atlantic
from its western side, where its altitude is about 2300 feet. There it
is bounded by the Iberian mountains, which begin at the point where the
Pyrenees take the name of the Cantabrian chain, and run in a tortuous
south-easterly direction through all Spain, constituting the eastern
boundary of Valencia and Murcia, and sending many branches through those
provinces to the Mediterranean: its most elevated point is the Sierra
Urbion.
Four nearly parallel ranges of mountains originate in this limiting
chain, running from E.N.E. to W.S.W. diagonally across the peninsula to
the Atlantic. Of these, the high Castilian chain of the Guadarama and
the Sierra de Toledo cross the table-land, the Sierra Morena, so called
from the dingy colour of its forests of Hermes oak, on the southern
edge; and lastly, the Sierra Nevada, though only 100 miles long and 50
broad, the finest range of mountains in Europe after the Alps, traverses
the plains of Andalusia and Grenada. The table-land is monotonous and
bare of trees; the plains of Old Castile are as naked as the Steppes of
Siberia, and uncultivated, except along the banks of the rivers. Corn
and wine are produced in abundance on the wide plains of New Castile and
Estremadura: other places serve for pasture. The table-land becomes more
fertile as it extends towards Portugal, which is altogether more
productive than Spain, though the maritime provinces of the latter on
the Mediterranean are luxuriant and beautiful, with a semi-tropical
vegetation.
Granite, crystalline strata, and primary fossiliferous rocks prevail
chiefly in the Spanish mountains, and give them their peculiar, bold,
serrated aspect. The valleys between the parallel ranges, through which
the great Spanish rivers flow to the Atlantic, appear to have been at
one time the basins of lakes.
The mass of high land is continued through the south of France, at a
much lower elevation, by chains of hills and table-lands, the most
remarkable of which are the Montagnes Noires, and the great plateau of
Auvergne, once the theatre of violent volcanic action. It continued from
the beginning to the middle of the tertiary period, so that there are
cones and craters of various ages and perfect form: some of the highest,
as the Puy de Dôme, are trachytic domes of elevation; Mont d’Or, 6200
feet high, is a portion of an immense crater of elevation.[22] The
volcanic mountains of Auvergne, and the Cévennes, which are a little
lower, are the most remarkable of the French system; the offsets of the
latter reach the right bank of the Rhone. In fact, the French mountains
are the link between the more elevated masses of Western and Eastern
Europe.
The eastern and highest part of the European portion of the
mountain-zone begins to rise above the low-lands about the 52d parallel
of north latitude, ascending by terraces, groups, and chains of
mountains, through six or seven degrees of latitude, till it reaches its
highest point in the great range of the Alps and Balkan. The descent on
the south side of this lofty mass is much more rapid and abrupt, and the
immediate offsets from the Alps shorter; but, taking a very general
view, the Apennines and mountains of Northern Sicily, those of Greece
and the southern part of Turkey in Europe, with all the islands of the
adjacent coasts, are but outlying members of the general protuberance.
The principal chain of the Hyrcanian mountains, the Sudetes, and the
Carpathian mountains, form the northern boundary of these high lands:
the first, consisting of three parallel ridges, extends from the right
bank of the Rhine to the centre of Germany, about 51° or 52° of N. lat.,
with a mean breadth of about 100 miles, and terminates in the knot of
the Fichtelberge, covering an area of 9000 square miles, on the confines
of Bavaria and Bohemia. The Sudetes begin on the east of this group,
and, after a circuit of 300 miles round Bohemia, terminate at the small
elevated plain of the Upper Oder, which connects them with the
Carpathian mountains. No part of these limiting ranges attains the
height of 5000 feet, except the Carpathians, some of which are very
high. They consist of mountain-groups united by elevated plains, rather
than of a single chain: the Tatra mountains, bisected by the 20th
meridian, is their loftiest point. This range is high also in
Transylvania, before it reaches the Danube, which divides it from a
secondary branch of the Balkan. Spurs decline in undulations from these
limiting chains on the great northern plain, and the country to the
south, intervening between them and the Alps, is covered with an
intricate network of mountains and plains of moderate elevation.
The higher Alps, which form the western crest of the elevated zone, may
be said to begin at the Cape della Melle on the Gulf of Genoa, and bend
round by the west and north to Mont Blanc; then turning E.N.E. they run
through the Grisons and Tyrol to the Great Glockner, in 40° 7ʹ N. lat.,
and 12° 43ʹ E. long., where the higher Alps terminate a course 420 miles
long. All this chain is lofty; much of it is above the line of perpetual
congelation; the most elevated part lies between the Col de la Seigne,
on the western shoulder of Mont Blanc, and the Simplon. The highest
mountains in Europe are comprised within this space, not more than 60
miles long, where Mont Blanc, the highest of all, has an absolute
elevation of 15,759·8 feet. The central ridge of the higher Alps is
jagged with peaks, pyramids, and needles of bare and almost
perpendicular rock, rising from fields of perpetual snow and rivers of
ice to an elevation of 14,000 feet. Many parallel chains and groups,
alike rugged and snowy, press on the principal crest, and send their
flanks far into the lower grounds. Innumerable secondary branches,
hardly lower than the main crest, diverge from it in various directions;
of these, the chain of the Bernese Alps is the highest and most
extensive. It breaks off at the St. Gothard, in a line parallel to the
principal chain, separates the Valais from the Canton of Berne, and with
its ramifications forms one of the most remarkable groups of mountain
scenery in Europe. Its endless maze of sharp ridges and bare peaks,
mixed with gigantic masses of pure snow, fading coldly serene into the
blue horizon, present a scene of sublime quiet and repose, unbroken but
by the avalanche or the thunder.
At the Great Glockner the range of the Alps, hitherto undivided, splits
into two branches, the Noric and Carnic Alps: the latter is the
continuation of the chief stem. Never rising to the height of perpetual
snow, it separates the Tyrol and Upper Carinthia from the Venetian
States, and, taking the name of the Julian Alps at Mont Terglou, runs
east till it joins the Eastern Alps, or Balkan, under the 18th meridian.
Offsets from this chain cover all the neighbouring countries.
It is difficult to estimate the width of the Alpine chain: that of the
higher Alps is about 100 miles; it increases to 150 east of the Grisons,
and amounts to 200 between the 15th and 16th meridians, but is not more
than 80 at its junction with the Balkan.
The Stelvio, 9174 feet above the sea, is the highest carriage-pass in
these mountains. That of St. Gothard goes directly over the crest of the
Alps. Passes very rarely go over the summit of a mountain; they
generally cross the watershed, ascending by the valley of a torrent, and
descending by a similar path on the other side.
The frequent occurrence of extensive deep lakes is a peculiar feature in
European mountains, rarely to be met with in the Asiatic system, except
in the Altaï and on the elevated plains.
With the exception of the Jura, whose pastoral summit is about 3000 feet
above the sea, there are no elevated table-lands in the Alps: the
tabular form, so eminently characteristic of the Asiatic high lands,
begins in the Balkan. The Oriental peninsula rises by degrees from the
Danube to Bosnia and Upper Macedonia, which are some hundred feet above
the sea; and the Balkan extends 600 miles along this elevated mass, from
the Julian Alps to Cape Eminec on the Black Sea. It begins by a
table-land 70 miles long, traversed by low hills, ending, towards
Albania and Myritida, in precipitous limestone rocks from 6000 to 7000
feet high. Rugged mountains, all but impassable, succeed to this, in
which the domes and needles of the Schandach, or ancient Scamus, are
covered with perpetual snow. Another table-land follows, whose marshy
surface is bounded by mural precipices at Mount Arbelus, near the town
of Sophia. There the Hemus, or Balkan properly so called, begins, and
runs in parallel ridges, separated by longitudinal valleys, to the Black
Sea, dividing the plains between the Lower Danube and the Propontis into
nearly equal parts. The central ridge is passable in few places, and
where there is no lateral ridge the precipices descend at once to the
plains.
The Balkan is everywhere rent by terrific fissures across the chains and
table-lands, so deep and narrow that daylight is almost excluded. These
chasms afford the safest passes across the range; the others along the
faces of the precipices are frightful.
The Mediterranean is the southern boundary of the elevated zone of
Eastern Europe, whose last offsets rise in rocky islands along the
coasts. The crystalline mountains of Sardinia and Corsica are outlying
members of the Maritime Alps, while shorter offsets end in the plains of
Lombardy, forming the magnificent scenery of the Italian lakes. Even the
Apennines, whose elevation has given its form to the peninsula of Italy,
are but secondary on a greater scale to the broad central band, as well
as the mountains and high land in the north of Sicily, which form the
continuance of the Calabrian chain.
The Apennines, beginning at the Maritime Alps, enclose the Gulf of
Genoa, and run through the centre of Italy in parallel ranges to the
middle of Calabria, where they split into two branches, one of which
goes to Capo de Leuca, on the Gulf of Torento, the other to Cape
Spartivento, in the Straits of Messina. The whole length is about 800
miles. None of the Apennines come within the line of perpetual snow,
though it lies nine months in the year on the Gran Sasso d’ltalia, 9521
feet high, in Abruzza Ulteriore.
Offsets from the Julian and Eastern Alps render Dalmatia and Albania
perhaps the most rugged tract in Europe; and the Pindus, which forms the
watershed of Greece, diverges from the latter chain, and, running south
200 miles, separates Albania from Macedonia and Thessaly.
Greece is a country of mountains, and, although none are perpetually
covered with snow, it lies nine months on several of their summits. The
chains terminate in strongly projecting headlands, which reach far into
the sea, and reappear in the numerous islands and rocks which stud that
deeply-indented coast. The Grecian mountains, like the Balkan, are torn
by transverse fractures. The defile of Blatamana and the Gulf of
Salonica are examples. The Adriatic, the Dardanelles, and the Sea of
Marmora limit the secondaries of the southern part of the Balkan.
The valleys of the Alps are long and narrow; those among the mountains
of Turkey in Europe and Greece are mostly caldron-shaped hollows, often
enclosed by mural rocks. Many of these cavities of great size lie along
the foot of the Balkan. In the Morea they are so encompassed by
mountains that the water has no escape but through the porous soil. They
consist of tertiary strata, which had formed the bottom of lakes.
Caldron-shaped valleys occur also in most volcanic countries, as Sicily,
Italy, and central France.
The table-lands which constitute the tops of mountains or of
mountain-chains are of a different character from those terraces by
which the high lands slope to the low. The former are on a small scale
in Europe, and of a forbidding aspect, with the exception of the Jura,
which is pastoral, whereas the latter are almost always habitable and
cultivated. The mass of high land in south-eastern Europe shelves on the
north to the great plain of Bavaria, 3000 feet high; Bohemia, which
slopes from 1500 to 900 feet; and Hungary, from 4000 above the sea to
300. The descent on the south of the Alps is six or seven times more
rapid, because the distance from the axis of the chain is shorter.
It is scarcely possible to estimate the quantity of ice on the Alps; it
is said, however, that, independent of the glaciers in the Grisons,
there are 1500 square miles of ice in the Alpine range, from 80 to 600
feet thick. There are no glaciers east of the Great Glockner, except on
the small group of Hallstadt. Thirty-four bound the snowy regions of
Mont Blanc, and 95 square miles of snow and ice clothe that mountain.
Some glaciers have been permanent and stationary in the Alps time
immemorial, while others now occupy ground formerly bearing corn or
covered with trees, which the irresistible force of the ice has swept
away. These ice-rivers, formed on the snow-clad summits of the
mountains, fill the hollows and high valleys, hang on the declivities,
or descend by their weight through the transverse valleys to the plains,
where they are cut short by the increased temperature, and deposit those
accumulations of rocks and rubbish, called moraines, which had fallen
upon them from the heights above; but their motion is so slow, that six
generations may pass before a stone fallen on the upper end of a long
glacier can reach the moraine. In the Alps, the glaciers move at the
rate of from 12 to 25 feet annually, and, as in rivers, the motion is
most rapid in the centre, and slower at the sides and bottom on account
of friction. It is slower in winter, yet it does not cease, because the
winter’s cold penetrates the ice, as it does the ground, only to a
limited depth. Glaciers are not of solid ice; they consist of a mixture
of ice, snow, and water; so that they are in some degree flexible and
viscous, but acquire more solidity as they descend to lower levels;
evaporation goes on at their surface, but they are not consumed by it.
The front is perpetually melting, but maintains a permanent form; it is
steep and inaccessible, owing to the figure of the ground over which it
tumbles in its icy cascade, sometimes 1000 feet high. The middle course
is rather level, the higher part very steep, and the surface is uneven
and rent by crevices into which the purest blue streams fall in rushing
cascades while the sun is up, but they freeze at his setting, and then a
death-like silence prevails. The rocks and stones that fall on them from
the surrounding heights protect the ice below from the sun which melts
it all around, so that at last they rest on elevated pinnacles till they
fall off by their weight, and in this manner those numerous pyramids are
formed with which the surface is bristled. Throughout much of the length
of a glacier the winter’s snow melts from its surface as completely as
it does from the ground; it is fed from above, for in the upper part the
snow never melts, but accumulates in a stratified form and is
consolidated. In some of the largest glaciers, where there is a
difference of 4000 feet in height between the origin and termination,
the pressure is enormous and irresistible, carrying all before it; even
the thickest forest is overwhelmed and crushed.
Glaciers advance or retreat according to the severity or mildness of the
season; they have been advancing in Switzerland of late years, but they
are subject to cycles of unknown duration. From the moraines, as well as
the striæ engraven on the rocks over which they have passed, M. Agassiz
has ascertained that the valley of Chamouni was at one time occupied by
a glacier that had moved towards the Col de Balme. A moraine 2000 feet
above the Rhone at St. Maurice would appear to indicate that, at a
remote period, glaciers had covered Switzerland to the height of 2155
feet above the Lake of Geneva.
Their increase is now limited by various circumstances—as the mean
temperature of the earth, which is always above the freezing-point in
those latitudes; excessive evaporation; and blasts of hot air, which
occur at all heights, in the night as well as in the day, from some
unknown cause. They are not peculiar to the Alps, but have been observed
also in the glaciers of the Andes. From the heat of the valley thawing
the ice, the natural springs that rise under the glacier as they do
elsewhere, the heat of the earth, the melting of the glacier itself, the
rain that falls on its surface, which rushes down its crevices, a stream
of turbid water is formed which works out an icy cavern at the
termination of the glacier and flows through it into the lower ground.
Thus, a glacier “begins in the clouds, is formed by the mountains, and
ends in the ocean.”[23]
Granite no doubt forms the base of the mountain system of Eastern
Europe, though it more rarely comes into view than might have been
expected. Crystalline schists of various kinds are enormously developed,
and generally form the most elevated pinnacles of the Alpine crest and
its offsets, and also the principal chains in Greece and Turkey in
Europe; but the secondary fossiliferous strata constitute the chief
mass, and often rise to the highest summits; indeed, secondary
limestones occupy a great portion of the high land of Eastern Europe.
Calcareous rocks form two great mountain-zones on each side of the
central chain of the Alps, and rise occasionally to altitudes of 10,000
or 12,000 feet. They constitute a great portion of the central range of
the Apennines, and fill the greater part of Sicily. They are extensively
developed in Turkey in Europe, where the plateau of Bosnia with its high
lands on the south, part of Macedonia, and Albania with its islands, are
principally composed of them.[24] Tertiary strata of great thickness
rest on the flanks of the Alps, and rise in some places to a height of
5000 feet; zones of the older Pleiocene period flank the Apennines on
each side, filled with organic remains; and half of Sicily is covered
with the Pleiocene strata. It appears that the Atlas, the Sierra Morena
and most of the Spanish mountains, the central chain of the Caucasus,
and the Balkan, were raised before the period of the erratic blocks.
From numerous dislocations in the strata, the Alps appear to have been
heaved up by many violent and repeated convulsions, separated by
intervals of repose, and different parts of the chain have been raised
at different times; for example, the Maritime Alps and the south-western
part of the Jura mountains were raised previously to the formation of
the chalk: but the tertiary period appears to have been that of the
greatest commotions; for nearly two-thirds of the lands of Europe have
risen since the beginning of that epoch, and those that existed then
acquired additional height, though some sank below their original level.
During that time the Alps acquired an additional elevation of between
2000 and 3000 feet; Mont Blanc then attained its present altitude; the
Apennines rose 1000 or 2000 feet higher; and the Carpathians seem to
have gained an accession of height since the seas were inhabited by the
existing species of animals.[25]