in such abundance, and gigantic saurians were living, the dry land, from
pole to pole, was probably less than it now is in the South Pacific and the
Indian Ocean. We shall see, in a subsequent part of this work, how this
preponderating quantity of water, combined with other causes, must have
contributed to raise the temperature and induce a greater uniformity of
climate. Here we would only remark in considering the gradual extension of
the dry land, that, shortly before the 'disturbances' which at longer or
shorter intervals caused the sudden destruction of so great a number of
colossal vertebrata in the 'diluvial period', some parts of the present
continental masses must have been completely separated from one another.
There is a great similarity in South America and Australia between still
living and extinct species of animals. In New Holland, fossil remains of
the kangaroo have been found, and in New Zealand the semi-foxxilized bones
of an enormous bird, resembling the ostrich, the dinornis of Owen,* which is
nearly allied to the present spteryx, and but little so to the recently
extinct dronte (dodo) of the island of Rodriguez.
[[footnote] *[See 'American Journal of Science', vol. xiv., p. 187; and
'Medals of Creation', vol. ii., p. 817; 'Trans. Zoolog. Society of London',
vol. ii; 'Wonders of Geology', vol. i., p. 129.] -- Tr.
The form of the continental portions of the earth may, perhaps, in a great
measure, owe their elevation above the surrounding level of the water to the
eruption of quartzose porphyry, which overthrew with violence the first
great vegetation from which the matrial of our present coal measures was
formed. The portions of the earth's surface which we term plains are
nothing more than the broad summits of hills and mountains whose bases rest
on the bottom of the ocean. Every plain is, therefore, when considered
according to its submarine relations, an 'elevated plateau', whose
inequalities have been covered over by horizontal deposition of new
sedimentary formations and by the accumulation of alluvium.
p 288
Among the general subjects of contemplation appertaining to a work of this
nature, a prominent place must be given, first, in the consideration of the
'quantity' of the land raised above the level of the sea, and next, to the
individual configuration of each part, either in relation to horizontal
extension (relations of form) or to vertical elevation (hypsometrical
relations of mountain-chains). Our planet has two envelopes, of which one,
which is general -- the atmosphere -- is composed of an elastic fluid, and
the other -- the sea -- is only locally distributed, surrounding, and
therefore modifying, the form of the land. These two envelopes of air and
sea constitute a natural whole, on which depend the difference of climate on
the earth's surface, according to the relative extension of the aqueous and
solid parts, the form and aspect of the land, and the direction and
elevation of mountain chains. A knowledge of the reciprocal action of air,
sea, and land teaches us that great meteorological phenomena can not be
comprehended when considered independently of geognostic relations.
Meteorology, as well as the geography of plants and animals, has only begun
to make actual progress since the mutual dependence of the phenomena to be
investigated has been fully recognized. The word climate has certainly
special reference to the character of the atmosphere, but this character is
itself dependent on the perpetually concurrent influences of the ocean,
which is universally and deeply agitated by currents having a totally
opposite temperature, and of radiation from the dry land, which varies
greatly in form, elevation, color, and fertility, whether we consider its
bare, rocky portions, or those that are covered with arborescent or
herbaceous vegetation.
In the present condition of the surface of our planet, the area of the solid
is to that of the fluid parts as 1:2 4/5ths (according to Rigaud, as
100:270).*
[footnote] *See 'Transactions of the Cambridge Philosophical Society', vcl.
vi., Part ii., 1837, p. 297. Other writers have given the ratio as 100:284.
The islands form scarcely 1/22d of the continental masses, which are so
unequally divided that they consist of three times more land in the northern
than in the southern hemisphere; the latter being, therefore, pre-eminently
oceanic. From 40 degrees south latitude to the Antarctic pole the earth is
almost entirely covered with water. The fluid element predominates in like
manner between the eastern shores of the Old and the western shores of the
New Continent, being only interspersed with some few insular groups. The
learned hydrographer Fleurieu has very justly named this
p 289
vast oceanic basis, which, under the tropics, extends over 145ºdegrees of
longitude, the 'Great Ocean', in contradistinction to all other seas. The
southern and western hemispheres (reckoning the latter from the meridian of
Teneriffe) are therefore more rich in water than in any other region of the
whole earth.
These are the main points involved in the consideration of the relative
quantity of land and sea, a relation which exercises so important an
influence on the distribution of temperature, the variations in atmospheric
pressure, the direction of the winds, and the quantity of moisture contained
in the air, with which the development of vegetation is so essentially
connected. When we consider that nearly three fourths of the upper surface
of our planet are covered with water,* we shall be less surprised at the
imperfect condition of meteorology before the beginning of the present
century, since it is only during the subsequent period that numerous
accurate observations on the temperature of the sea at different latitudes
and at different seasons have been made and numerically compared together.
[footnote] *In the Middle Ages, the opinion prevailed that the sea covered
one seventh of the surface of the globe, an opinion which Cardinal d'Ailly
('Imago Mundi', cap. 8) founded on the fourth apocryphal book of Esdras.
Columbus, who derived a great portion of his cosmographical knowledge from
the cardinal's work, was much interested in upholding this idea of the
smallness of the sea, to which the misunderstood expression of "the ocean
stream" contributed not a little. See Humboldt, 'Examen Critique de l'Hist.
de la Geographie', t. i.,
p. 186.
The horizontal configuration of continents in their general relations of
extension was already made a subject of intellectual contemplation by the
ancient Greeks. Conjectures were advanced regarding the maximum of the
extension from west to east, and Dicaearchus placed it, according to the
testimony of Agathemerus, in the latitude of Rhodes, in the direction of a
line passing from the Pillars of Hercules to Thine. This line, which has
been termed 'the parallel of the diaphragm of Dicaearchus', is laid down
with an astronomical accuracy of position, which, as I have stated in
another work, is well worthy of exciting surprise and admiration.*
[footnote] *Agathemerus, in Hudson, 'Geographi Minores', t. ii., p. 4. See
Humboldt, 'Asie Centr.', t. i., p. 120-125.
Strabo, who was probably influenced by Eratosthenes, appears to have been so
firmly convinced that this parallel of 36 degrees was the maximum of the
extension of the then existing world, that he supposed it had some intimate
connection with the form of the earth, and therefore places under this line
the continent whose existence
p 290
he divined in the northern hemisphere, between Theria and the coasts of
Thine.*
[footnote] *Strabo, lib. i., p. 65, Casaub. See Humboldt, 'Examen Crit.',
t. i., p. 152.
As we have already remarked, one hemisphere of the earth (whether we divide
the sphere through the equator or through the meridian of Teneriffe) has a
much greater expansion of elevated land than the opposite one: these two
vast ocean-girt tracts of land, which we term the eastern and western, or
the Old and New Continents, present, however, conjointly with the most
striking contrasts of configuration and position of their axes, some
similarities of form, especially with reference to the mutual relations of
their opposite coasts. In the eastern continent, the predominating
direction -- the position of the major axis -- inclines from east to west
(or, more correctly speaking, from southwest to northeast), while in the
western continent it inclines from south to north (or, rather, from
south-southeast to north-northwest). Both terminate to the north at a
parallel coinciding nearly with that of 70ºdegrees, while they extend to
the south in pyramidal points, having submarine prolongations of islands and
shoals. Such, for instance, are the Archipelago of Tierra del Fuego, the
Lagullas Bank south of the Cape of Good Hope, and Van Diemen's Land,
separated from New Holland by Bass's Straits. Northern Asia extends to the
above parallel at Cape Taimura, which, according to Krusenstern, is 78
degrees 16', while it falls below it from the mouth of the Great
Tschukotsehja River eastward to Behring's Straits, in the eastern extremity
of Asia -- Cook's East Cape -- which, according to Beechey, is only 66
degrees E.*
[footnote] *On the mean latitude of the Northern Asiatic shores, and the
true name of Cape Taimura (Cape Siewere-Wostotschnoi), and Cape Northeast
(Schalagskoi Mys), see Humboldt, 'Asie Centrale', t. iii., p. 35, 37.
The northern shore of the New Continent follows with tolerable exactness the
parallel of 70 degrees, since the lands to the north and south of Barrow's
Strait, from Boothia Felix and Victoria Land, are merely detached islands.
The pyramidal configuration of all the southern extremities of continents
belongs to the 'similtudines physicae in configuratione mundi', to which
Bacon already called attention in his 'Novum Organon', and with which
Reinhold Foster, one of Cook's companions in his second voyage of
circumnavigation, connected some ingenious considerations. On looking
eastward from the meridian of Teneriffe, we perceive that the southern
extremities of the three continents, viz., Africa as the extreme
p 291
of the Old World, Australia, and South America, successively approach nearer
toward the south pole. New Zealand, whose length extends fully 12 degrees
of latitude, forms an intermediate link between Australia and South America,
likewise terminating in an island, New Leinster. It is also a remarkable
circumstance that the greatest extension toward the south falls in the Old
Continent, under the same meridian in which the extremest projection toward
the north pole is manifested. This will be perceived on comparing the Cape
of Good Hope and the Lagullas Bank with the North Cape of Europe, and the
peninsula of Malacca with Cape Taimura in Siberia.*
[footnote] *Humboldt, 'Asie Centrale', t. i., p. 198-200. The southern
point of America, and the Archipelago which we call Terra del Fuego, lie in
the meridian of the northwestern part of Baffin's Bay, and of the great
polar land, whose limits have not as yet been ascertained, and which,
perhaps, belongs to West Greenland.
We know not whether the poles of the earth are surrounded by land or by a
sea of ice. Toward the north pole the parallel of 82 degrees 55' has been
reached, but toward the south pole only that of 78 degrees 10'.
The pyramidal terminations of the great continents are variously repeated on
a smaller scale, not only in the Indian Ocean and in the peninsulas of
Arabia, Hindostan, and Malacca, but also, as was remarked by Eratosthenes
and Polybius, in the Mediterranean, where these writers had ingeniously
compared together the forms of the Iberian, Italian, and Hellenic
peninsulas.*
[footnote] *Strabo, lib. ii., p. 92, 108, Cassaub.
Europe, whose area is five times smaller than that of Asia, may almost be
regarded as a multifariously articulated western peninsula of the more
compact mass of the ontinent of Asia, the climatic relations of the former
being to those of the latter as the peninsula of Brittany is to the rest of
France.
[footnote] *Humboldt, 'Asie Centrale', t. iii., p. 25. As early as the
year 1817, in my work 'De distributione Geographica Plantarum, secundum
caels temperiem et altitudinem Montium', I directed attention to the
important influence of compact and of deeply-articulated continents on
climate and human civilization, "Regiones vel per sinus lunatos in longa
cornua porrectae, angulois littorum recessibus quasi membratim discerptae,
vel spatia patentia in immensum, quorum littora nullis incisa angulis ambit
sine aufractu oceanus" (p. 81, 182). On the relations of the extent of
coast to the area of a continent (considered in some degree as a measure of
the accessibility of the interior), see the inquiries in Berghaus, 'Annalen
der Erdkunde', bd. xii., 1835, s. 490, and 'Physikal. Atlas', 1839, No.
iii., s. 69.
The influence exercised by the articulation and higher development of the
form of a continent on the moral and intellectual condition of nations was
remarked by Strabo,* who extols
p 292
the varied form of our small continent as a special advantage.
[footnote] *Strabo, lib. ii., p. 92, 198. Casaub.
Africa* and South America, which manifest so great a resemblence in their
configuration, are also the two continents that exhibit the simplest
littoral outlines.
[footnote] *Of Africa, Pliny says (v. 1), "Nec alia pars terrarum paudiores
recipit sinus." The small Indian peninsula on this side the Ganges present,
in its triangular outline, a third analogous form. In ancient Greece there
prevailed an opinion of the regular configuration of the dry land. There
were four gulfs or bays, among which the Persian Gulf was placed in
opposition to the Hyrcanian or Caspian Sea (Arrian, vii., 16; Plut., 'in
vita Alexandri', cap. 44; Dionys. Perieg., v. 48 and 630, p. 11, 38,
Bernh.). These four bays and the isthmuses were, according to the optical
fancies of Agesianax, supposed to be reflected in the moon (Plut., 'de Facie
in Orbem Lunae', p. 921, 19). Respecting the 'terra quadrifida', or four
divisions of the dry land, of which two lay north and two south of the
equator, see Macrobius, 'Comm. in Somnium Scipionis', ii., 9. I have
submitted this portion of the geography of the ancients, regarding which
great confusion prevails, to a new and careful examination, in my 'Examen
Crit. de l'Hist. de la Geogr.', t. i., p. 119, 145, 180-185, as also in
'Asie Centr.', t. ii., p. 172-178.
It is only the eastern shores of Asia, which, broken as it were by the force
of the currents of the ocean* ('fractas ex aequore terra'), exhibit a
richly-variegated configuration, peninsulas and contiguous islands
alternating from the equator to 60 degrees north latitude.
[footnote] *Fleurieu, in 'Voyage de Marchand autour du Monde', t. iv., p.
38-42.
Our Atlantic Ocean presents all the indications of a valley. It is as if a
flow of eddying waters had been directed first toward the northeast, then
toward the northwest, and back again to the northeast. The parallelism of
the coasts north of 10 degrees south latitude, the projecting and receding
angles, the convexity of Brazil opposite to the Gulf of Guinea, that of
Africa under the same parallel, with the Gulf of the Antilles, all favor
this apparently speculative view.*
[footnote] *Humboldt, in the 'Journal de Physique', liii., 1799, p. 33; and
'Rel. Hist.', t. ii., p. 19; t. iii., p. 189, 198.
In this Atlantic valley, as is almost every where the case in the
configuration of large continental masses, coasts deeply indented, and rich
in islands, are situated opposite to those possessing a different character.
I long since drew attention to the geognostic importance of entering into a
comparison of the western coast of Africa and of South America within the
tropics. The deeply curved indentation of the African continent at Fernando
Po, 4 degrees 30' north latitude, is repeated on the coast of the Pacific at
18 degrees 15' south latitude, between the Valley of Arica and the Morro de
Juan Diaz, where the Peruvian coast suddenly changes the direction from
wouth to north which it had previously followed, and inclines to the
northwest. This change
p 293
of direction extends in like manner to the chain of the Andes, which is
divided into two parallel branches affecting not only the littoral
portions,* but even the eastern Cordilleras.
[footnote] *Humboldt, in Poggendorf's 'Annalen der Physik', bd. xl., s.
171. On the remarkable fiord formation at the southeast end of America, see
Darwin's Journal ('Narrative of the Voyages of the Adventure and Beagle',
vol. iii.), 1839, p. 266. The parallelism of the two mountain chains is
maintained from 5 degrees north latitude. The change in the direction of
the coast at Arica appears to be in consequence of the altered course of the
fissure, above which the Cordillera of the Andes has been upheaved.
In the latter, civilization had its earliest seat in the South American
plateaux where the small Alpine lake of Titicaca bathes the feet of the
colossal mountains of Sorata and Illimani. Further to the south, from
Valdiva and Chiloë (40 degrees to 42 degrees south latitude), through the
Archipelago 'de los Chonos' to 'Terra del Fuego', we find repeated that
singular configuration of 'fiords' (a blending of narrow and deeply-indented
bays), which in the Northern hemisphere characterizes the western shores of
Norway and Scotland.
These are the most general considerations suggested by the study of the
upper surface of our planet with reference to the form of continents, and
their expansion in a horizontal direction. We have collected facts and
brought forward some analogies of configuration in distant parts of the
earth, but we do not venture to regard them as fixed laws of form. When the
traveler on the declivity of an active volcano, as, for instance, of
Vesuvius, examines the frequent partial elevations by which portions of the
soil are often permanently upheaved several feet above their former level,
either immediately precediing or during the continuance of an eruption, thus
forming roof-like or flattened summits, he is taught how accidental
conditions in the expression of the force of subterranean vapors, and in the
resistance to be overcome, may modify the feeble perturbations in the
equilibrium of the internal elastic forces of our planet may have inclined
them more to its norther than to its southern direction, and caused the
continent in the eastern part of the globe to present a broad mass, whose
major axis is almost parallel with the equator, while in the western and
more oceanic part the southern extremity is extremely narrow.
Very little can be empirically determined regarding the causal connection of
the phenomena of the formation of continents, or of the analogies and
contrasts presented by their
p 294
configuration. All that we know regarding this subject resolves itself into
this one point, that the active cause is subterranean; that continents did
not arise at once in the form they now present, but were, as we have already
observed, increased by degrees by means of numerous oscillatory elevations
and depressions of the soil, or were formed by the fusion of separate
smaller continental masses. Their present form is, therefore, the result of
two causes, which have exercised a consecutive action the one on the other;
the first is the expression of subterranean force, whose direction we term
accidental, owing to our inability to defint it, from its removal from
within the sphere of our comprehension, while the second is derived from
forces acting on the surface, among which volcanic eruptions, the elevation
of mountains, and currents of sea water play the principal parts. How
totally different would be the condition of the temperature of the earth,
and consequently, of the state of vegetation, husbandry, and human society,
if the major axis of the New Continent had the same direction as that of the
Old Continent; if, for instance, the Cordilleras, instead of having a
southern direction, inclined from east to west; if there had been no
radiating tropical continent, like Africa, to the south of Europe; and if
the Mediterranean, which was once connected with the Caspian and Red Seas,
and which has become so powerful a means of furthering the
intercommunication of nations, had never existed, or if it had been elevated
like the plains of Lombardy and Cyrene?
The changes of the reciprocal relations of height between the fluid and
solid portions of the earth's surface (changes which, at the same time,
determine the outlines of continents, and the greater or lesser submersion
of low lands) are to be ascribed to numerous unequally working causes. The
most powerful have incontestably been the force of elastic vapors inclosed
in the interior of the earth, the sudden change of temperature of certain
dense strata,* the unequal secular loss of
p 295
heat experienced by the crust and nucleus of the earth, occasioning ridges
in the solid surface, local modifications of gravitation,** and, as a
consequence of these alterations, in the curvature of a portion of the
liquid element.
[footnote] *De la Beche, 'Sections and Views illustrative of Geological
Phenomena', 1830, tab. 40; Charles Babbage, 'Observations on the Temple of
Serapis at Pozzuoli, near Naples, and on certain Causes which may produce
Geological Cycles of great Extent', 1834. "If a stratum of sandstone five
miles in thickness should have its temperature raised about 100 degrees, its
surface would rise twenty-five feet. Heated beds of clay would, on the
contrary, occasion a sinking of the ground by their contraction." See
Bischof, 'Wurmelehre des Innern unseres Erdkorpers', s. 303, concerning the
calculations for the secular elevation of Sweden, on the supposition of a
rise by so small a quantity as 7 degrees in a stratum of about 155,000 feet
in thickness, and heated to a state of fusion.
[footnote] **The opinion so implicitly entertained regarding the
invariability of the force of gravity at any given point of the earth's
surface, has in some degree been controverted by the gradual rise of large
portions of the earth's surface. See Bessel, 'Ueber Maas und Gewicht', in
Schumacher's 'Jahrbuch fur' 1840, s. 134.
According to the views generally adopted by geognosists in the present day
and which are supported by the observation of a series of well-attested
facts, no less than by analogy with the most important volcanic phenomena,
it would appear that the elevation of continents is actual, and not merely
apparent or owing to the configuration of the upper surface of the sea. The
merit of having advanced this view beloongs to Leopold von Buch, the
narrative of his memorable 'Travels through Norway and Sweden' in 1806 and
1807.*
[footnnote] *Th. ii. (1810), s. 389. See Hallstrom, in 'Kongl.
Vetenskaps-Academiens Handlingar' (Stockh.), 1823, p. 30; Lyell in the
'Philos. Trans.' for 1835; Blom (Amtmann in Budskerud), 'Stat. Beschr. von
Norwegen',1843, s. 89-116. If not before Von Buch's travels through
Scandinavia, at any rate before their publication, Playfair, in 1802, in his
illustrations of the Huttonian theory, § 393, and according to Keilhau ('Om
Landjardens Stigning in Norge', in the 'Nyt Magazine fur
Naturvidenskaberne'), and the Dane Jessen, even before the time of Playfair,
had expressed the opinion that it was not the sea which was sinking, but the
solid land of Sweden which was rising. Their ideas, however, were wholly
unknown to our great geologist, and exerted no influence on 'Norge
fremstillet efter dets naturlige og borgerlige Tilstand', Kjobenh., 1763,
sought to explain the causes of the changes in the relative levels of the
land and sea, basing his views on the early calculations of Celsius, Kalm,
and Dalin. He broaches some confused ideas regarding the possibility of an
internal growth of rocks, but finally declares himself in favor of an
upheaval of the land by earthquakes, "although," he observes, "no such
rising was apparent immediately after the earthquake of Egersund, yet the
earthquake may have opened the way for other causes producing such an
effect."
While the whole coast of Sweden and Finland, from Solvitzborg, on the limits
of Northern Scania, past Gefle to Tornea, and from Tornea to Abo,
experiences a gradual rise of four feet in a century, the southern part of
Sweden is, according to Neilson, undergoing a simultaneous depression.*
[footnote] *See Berzelius, 'Jahrsbericht uber die Fortschritte der
Physichen Wiss.', No. 18, s. 686. The islands of Saltholm, opposite to
Copenhagen, and Bjornholm, however, rise but very little -- Bjornholm
scarcely one foot in a century. See Forchhammer, in 'Philos. Magazine', 3d
Series, vol. ii., p. 309.