_I.--To the South American Coast_
The "Journal of Researches into the Natural History and
Geology of the Countries Visited during the Voyage of
H.M.S. Beagle Round the World" was Darwin's first popular
contribution to travel and science. His original journal
of the part he took in the expedition, as naturalist of
the surveying ships Adventure and Beagle, was published,
together with the official narratives of Captains Fitzroy
and King, a year after the return of the latter vessel to
England in October, 1836. It was not till 1845 that Darwin
issued his independent book, of which the following is an
epitome, written from the notes in his journal. It
immediately attracted considerable popular and scientific
attention, and many editions and cheap reprints have been
issued during the past half century. It is said that
Darwin at first considered himself more as a collector
than as a scientific worker; but experience soon brought
to him the keen enjoyment of the original investigator.
The most striking feature of the book is the combined
minuteness and breadth of his observations and
descriptions. There can be no doubt that it was the
gathered results of his discoveries, and the study of his
collected specimens of the zoology, botany, and geology of
the countries visited; his graphic presentation of their
physical geography; and their synthetic analysis, which
laid the foundations of his great generalisations of the
"Origin of Species." (See SCIENCE.)
After having been twice driven back by heavy south-west gales, H.M.S.
Beagle, a ten-gun brig, under the command of Captain Fitzroy, R.N.,
sailed from Devonport on December 27, 1831. The object of the expedition
was to complete the survey of Patagonia and Tierra del Fuego, commenced
under Captain King in 1826-30; to survey the shores of Chile, Peru, and
of some of the islands in the Pacific; and to carry a chain of
chronometrical measurements round the world.
On January 16, 1832, we touched at Porto Praya, St. Jago, in the Cape de
Verde archipelago, and sailed thence to Rio de Janeiro, Brazil. Delight
is a weak term to express the higher feelings of wonder, astonishment,
and devotion which fill the mind of a naturalist in wandering through
the Brazilian tropical forest. The noise from the insects is so loud
that it may be heard at sea several hundred yards from the shore, yet
within the recesses of the forest a universal silence seems to reign.
The wonderful and beautiful flowering parasites invariably struck me as
the most novel object in these grand scenes. Among the cabbage-palms,
waving their elegant heads fifty feet from the ground, were woody
creepers, two feet in circumference, themselves covered by other
creepers.
The humming birds are fond of shady spots, and these little creatures,
with their brilliant plumage, buzzing round the flowers with wings
vibrating so rapidly as scarcely to be visible, seek the tiny insects in
the calyx rather than the fabled honey. Insects are particularly
numerous, the bees excepted. The Beagle was employed surveying the
extreme southern and eastern coasts of America south of the Plata during
the two succeeding years. The almost entire absence of trees in the
pampas of Uruguay, the provinces of Buenos Ayres [now Argentina], and
Patagonia is remarkable.
Fifteen miles from the Rio Negro, the principal river on the whole line
of coast between the Strait of Magellan and the Plata, are several
shallow lakes of brine in winter, which in summer are converted into
fields of snow-white salt two and a half miles long and one broad. The
border of the lakes is formed of mud, which is thrown up by a kind of
worm. How surprising it is that any creature should be able to exist in
brine, and that they should be crawling among crystals of sulphate of
soda and lime!
The valley of the Rio Negro, broad as it is, has merely been excavated
out of the sandstone plain; and everywhere the landscape wears the same
sterile aspect.
_II.--Fossil Monsters of the Pampas_
The pampas are formed from the mud, gravel, and sand thrown up by the
sea during the slow elevation of the land; and the section disclosed at
Punta Alta, a few miles from Bahia Blanca, was interesting from the
number and extraordinary character of the remains of gigantic land
animals embedded in it. I also found remains of immense armadillo-like
animals on the banks of a tributary of the Rio Negro; and, indeed, I
believe that the whole area of the pampas is one wide sepulchre of these
extinct colossal quadrupeds. The following, which I unearthed, are now
deposited in the College of Surgeons, London.
(1) Head and bones of a _megatherium_, the huge dimensions of which are
expressed by its name; (2) the _megalonyx_, a great allied animal; (3)
the perfect skeleton of a _scelidorium_, also an allied animal, as large
as a rhinoceros, in structure like the Cape ant-eater, but in some other
respects approaching the armadilloes; (4) the _mylodon Darwinii_, a
closely related genus, and little inferior in size; (5) another gigantic
dental quadruped; (6) another large animal very like an armadillo; (7)
an extinct kind of horse (it is a marvellous fact in the history of the
mammalia that, in South America, a native horse should have lived and
disappeared, to be succeeded in after ages by the countless herds
descended from the few introduced with the Spanish colonists); (8) a
pachydermatous animal, a huge beast with a long neck like a camel; (9)
the toxodon, perhaps the strangest animal ever discovered; in size it
equalled an elephant, or _megatherium_, but was intimately related to
the Gnawers, the order which at the present day includes most of the
smallest quadrupeds; and judging from the position of the eyes, ears,
and nostrils, it was probably aquatic.
We have good evidence that these gigantic quadrupeds, more different
from those of the present day than the oldest of the Tertiary quadrupeds
of Europe, lived whilst the sea was peopled with most of its present
inhabitants. These animals migrated on land, since submerged, near
Behring's Strait, from Siberia into North America, and thence on land,
since submerged, in the West Indies into South America, where they
mingled with the forms characteristic of that southern continent, and
have since become extinct.
The existing animals of the pampas include the puma, the South American
lion, while the birds are numerous. The largest is the ostrich, which is
found in groups. The ostriches are fleet in pace, prefer running against
the wind, and freely take to the water. At first start they expand their
wings, and, like a vessel, make all sail. Of mammalia, the jaguar, or
South American tiger, is the most formidable. It frequents the wooded
and reedy banks of the great rivers. There are four species of
armadilloes, notable for their smooth, hard, defensive covering. Of
reptiles there are many kinds. One snake, a _trigonocephalus_, has in
some respects the structure of a viper with the habits of a rattlesnake.
The expression of this snake's face is hideous and fierce. I do not
think I ever saw anything more ugly, excepting, perhaps, some of the
viper-bats.
_III.--In the Extreme South_
From the Rio Plata the course of the Beagle was directed to the mouth of
the Santa Cruz river, on the coast of Patagonia. One evening, when we
were about ten miles from the bay of San Blas, vast numbers of
butterflies, in bands and flocks of countless myriads, extended as far
as the eye could range. One dark night, with a fresh breeze, the foam
and every part of the surface of the waves glowed with a pale light. The
vessel drove before her bows two billows of liquid phosphorus, and in
her wake she was followed by a milky train. I am inclined to consider
that the phosphorescence is the result of organic particles, by which
process (one is tempted almost to call it a kind of respiration) the
ocean becomes purified.
The geology of Patagonia is interesting. For hundreds of miles of coast
there is one great deposit composed of shells--a white pumiceous stone
like chalk, including gypsum and _infusoria_. At Port St. Julian it is
eight hundred feet thick, and is capped by a mass of gravel forming
probably one of the largest beds of shingle in the world, extending to
the foot of the Cordilleras. For 1,200 miles from the Rio Plata to
Tierra del Fuego the land has been raised by many hundred feet, and the
uprising movement has been interrupted by at least eight long periods of
rest, during which the sea ate deep back into the land, forming at
successive levels the long lines of cliffs, or escarpments, which
separate the different plains as they rise like steps one behind the
other. What a history of geological change does the simply constructed
coast of Patagonia reveal! In some red mud, capping the gravel, I
discovered fossil bones which showed the wonderful relationship in the
same continent between the dead and the living, and will, I have no
doubt, hereafter throw more light on the appearance of organic beings on
our earth and their disappearance from it than any other class of facts.
Patagonia is sterile, but is possessed of a greater stock of rodents
than any other country in the world. The principal animals are the
llamas, in herds up to 500, and the puma, which, with the condor and
other carrion hawks, preys upon them.
From the Strait of Magellan, the Beagle twice made a compass of the
Falkland Islands, and archipelago in nearly the same latitude. It is a
delicate and wretched land, everywhere covered by a peaty soil and wiry
grass of one monotonous colour. The only native quadruped is a large
wolf-like fox, which will soon be as extinct as the dodo. The birds
embrace enormous numbers of sea-fowl, especially geese and penguins. The
wings of a great logger-headed duck called the "steamer" are too weak
for flight; but, by their aid, partly by swimming, partly flapping, they
move very quickly. Thus we found in South America three birds who use
their wings for other purposes besides flight--the penguins as fins, the
"steamers" as paddles, and the ostrich as sails.
Tierra del Fuego may be described as a mountainous land, separated from
the South American continent by the Strait of Magellan, partly submerged
in the sea, so that deep inlets and bays occupy the place where valleys
should exist. The mountain-sides, except on the exposed western coasts,
are covered from the water's edge upwards to the perpetual snow-line by
one great forest, chiefly of beeches. Viewing the stunted natives on the
west coast, one can hardly conceive that they are fellow-creatures and
inhabitants of the same world; and I believe that in this extreme part
of South America man exists in a lower state of improvement than in any
other part of the globe. The zoology of Tierra del Fuego is very poor.
In the gloomy woods there are few birds, but where flowers grow there
are humming birds, a few parrots and insects, but no reptiles.
_IV.--The Wonders of the Cordilleras_
After encountering many adventures in these Antarctic seas, among which
was a narrow escape from shipwreck in a fierce gale off Cape Horn, and
amidst hitherto unexplored Antarctic islands, the Beagle set a course
northward in the open Pacific for Valparaiso, the chief seaport of
Chile, which was reached on July 23, 1834. Chile is a narrow strip of
land between the Cordilleras and the Pacific, and this strip itself is
traversed by many mountain lines which run parallel to the great range.
Between these outer lines and the main Cordilleras a succession of level
basins, generally opening into each other by narrow passages, extend far
to the southward. These basins, no doubt, are the bottoms of ancient
inlets and deep bays such as at the present day intersect every part of
Tierra del Fuego.
From November, 1834, to March, 1835, the Beagle was employed in
surveying the island of Chiloe and the broken line called the Chonos
Archipelago. This archipelago is covered by one dense forest, resembling
that of Tierra del Fuego, but incomparably more beautiful. There are few
parts of the world within the temperate regions where so much rain
falls. The winds are very boisterous, and the sky almost always clouded.
Fortunately, for once, while we were on the east side of Chiloe the day
rose splendidly clear, and we could see the great range of the Andes on
the mainland with three active volcanoes, each 7,000 feet high.
While at Valdivia, on the mainland, on February 20, 1835, the worst
earthquake ever recorded in Chile occurred, and it was followed for
twelve days by no less than 300 tremblings. A bad earthquake at once
destroys our oldest associations; the earth, the very emblem of
solidity, has moved beneath our feet like a thin crust over a fluid. One
second of time has created in the mind a strange idea of insecurity
which hours of reflection would not have produced. The most remarkable
effect was the permanent elevation of the land round the Bay of
Concepcion by several feet. The convulsion was more effectual in
lessening the size of the island of Quiriquina off the coast than the
ordinary wear and tear of the sea and weather during the course of a
whole century; but on the other hand, on the Island of St. Maria putrid
mussel-shells, still adhering to the rocks, were found ten feet above
high-water mark. Near Juan Fernandez Island a volcano uprose from under
the water close to the shore, and at the same instant two volcanoes in
the far-off Cordilleras bust forth into action.
The space from which volcanic matter was actually erupted is 720 miles
in one line and 400 miles in another line at right-angles from the
first; hence, in all probability, a subterranean lake of lava is here
stretched out of nearly double the area of the Black Sea. The frequent
quakings of the earth on this line of coast are caused, I believe, by
the rending of the strata, necessarily consequent on the tension of the
land when upraised, and their injection by fluidified rock. This rending
and injection would, if repeated often enough, form a chain of hills.
I made the passage of the Cordilleras to Mendoza, the capital of the
republic of that name, on horseback. The features in the scenery of the
Andes which struck me most were that all the main valleys have on both
sides a fringe, sometimes expanding into a narrow plain of shingle and
sand. I am convinced that these shingle terraces were accumulated during
the gradual elevation of the Cordilleras by the torrents delivering at
successive levels their detritus on the beach-heads of long, narrow arms
of the sea, first high up the valleys, then lower down and lower down as
the land slowly rose.
If this be so, and I cannot doubt it, the grand and broken chain of the
Cordilleras, instead of having been suddenly thrown up--as was till
lately the universal, and still is the common, opinion of
geologists--has been slowly upheaved in mass in the same gradual manner
as the coasts of the Atlantic and Pacific have arisen within the recent
period. The other striking features of the Cordilleras were the bright
colours, chiefly red and purple, of the utterly bare and precipitous
hills of porphyry; the grand and continuous wall-like dikes; the plainly
divided strata, which, where nearly vertical, formed the picturesque and
wild central pinnacles, but where less inclined composed the great
massive mountains on the outskirts of the range; and lastly, the smooth,
conical piles of fine and brightly-coloured detritus, which slope up
sometimes to a height of more than 2,000 feet.
It is an old story, but not less wonderful, to see shells which were
once crawling at the bottom of the sea now standing nearly 14,000 feet
above its level. But there must have been a subsidence of several
thousand feet as well as the ensuing elevation. Daily it is forced home
on the mind of the geologist that nothing, not even the wind that blows,
is so unstable as the level of the crust of the earth.
From Valparaiso to Coquimbo, and thence to Copiapo, in Northern Chile,
the country is singularly broken and barren. On some of the terraced
plains rising to the Cordilleras, covered with cacti, there were large
herds of llamas. At one point in the coast range great prostrate
silicified trunks of fir trees were very numerous, embedded in a
conglomerate. I discovered convincing proof that this part of the
continent of South America has been elevated near the coast from 400
feet to 1,300 feet since the epoch of existing shells; and further
inland the rise possibly may have been greater. From the evidence of
ruins of Indian villages at very great altitude, now absolutely barren,
and some fossil human relics, man must have inhabited South America for
an immensely long period.
From the port of Iquique, in Peru, a visit was made across the desert to
the nitrate of soda mines. The nitrate stratum, between two and three
feet thick, lies close to the surface, and follows for 150 miles the
margin of the plain. From the troubled state of the country, I saw very
little of the rest of Peru.
A month was spent in the Galapagos Archipelago--a group of volcanic
islands situated on the Equator between 500 and 600 miles westward of
the coast of America. The little archipelago is a little world within
itself. Hence, both in time and space, we seemed to be brought somewhere
near to that great fact, that mystery of mysteries, the first appearance
of new beings on this earth. The vegetation is scanty. The principal
animals are the giant tortoises, so large that it requires six or eight
men to lift one. The most remarkable feature of the natural history of
this archipelago is that the different islands are inhabited by
different kinds of tortoises; and so with the birds, insects, and
plants. One is astonished at the amount of creative force, if such an
expression may be used, displayed on these small, barren, and rocky
islands, and still more so at its diverse, yet analogous, action on
points so near each other.
_V.--The Coral Islands of the Indian Ocean_
Having completed the survey of the coasts and islands of the South
American continent, the Beagle sailed across the wide Pacific to Tahiti,
New Zealand, and Australia, in order to carry out the chain of
chronometrical measurements round the world. From Australasia a run was
then made for Keeling or Cocos Island in the Indian Ocean. This lonely
island, 600 miles from the coast of Sumatra, is an atoll, or lagoon
island. The land is entirely composed of fragments of coral.
There is, to my mind, much grandeur in the view of the outer shores of
these lagoon islands. The ocean, throwing its waters over the broad
barrier-like reef, appears an invincible, all-powerful enemy. Yet these
low, insignificant coral islets stand and are victorious; for here
another power, as an antagonist, takes part in the contest. Organic
forces separate the atoms of carbonate of lime, one by one, from the
foaming breakers, and unite them in a symmetrical structure. Let the
hurricane tear up its thousand huge fragments, yet what will that tell
against the accumulated labour of myriads of architects at work night
and day, month after month?
There are three great classes of coral reefs--atoll, barrier, and
fringing. Now, the utmost depth at which corals can construct reefs is
between twenty and thirty fathoms, so that wherever there is an atoll a
foundation must have originally existed within a depth of from twenty to
thirty fathoms from the surface. The coral formation is raised only to
that height to which the waves can throw up fragments and the winds pile
up sand. The foundation, such as a mountain peak, therefore, must have
sunk to the required level, and not have been raised, as has hitherto
been generally supposed.
I venture, therefore, to affirm that, on the theory of the upward growth
of the corals during the sinking of the land, all the leading features
of those wonderful structures, the lagoon-islands or atolls, as well as
the no less wonderful barrier-reefs, whether encircling small islands,
or stretching for hundreds of miles along the shores of a continent, are
simply explained. On the other hand, coasts merely fringed by reefs
cannot have subsided to any perceptible amount, and therefore they must,
since the growth of their corals, either have remained stationary or
have been upheaved.
The chronometrical measurements were completed in the Indian Ocean by a
visit to Mauritius, and thence, voyaging around the Cape of Good Hope,
to the islands of St. Helena and Ascension, in the Southern Atlantic,
and to the mainland of Brazil at Bahia and Pernambuco, from which the
course was set for home. The Beagle made the shores of England at
Falmouth on October 2, 1836, after an absence of nearly five years.
On a retrospect, among the scenes which are deeply impressed on my mind,
including the spectacles of the Southern Cross, the Cloud of Magellan,
and the other constellations of the Southern Hemisphere, the glacier
leading its blue stream of ice overhanging the sea in a bold precipice,
the lagoon-islands raised by the reef-building corals, the active
volcano, the overwhelming effects of a violent earthquake--none exceed
in sublimity the primeval forests undefaced by the hand of man, whether
those of Brazil, where the powers of Life are predominant, or those of
Tierra del Fuego, where Death and Decay prevail. Both are temples filled
with the varied productions of the God of nature. No one can stand in
those solitudes unmoved and not feel that there is more in man than the
mere breath of his body. And so with the boundless plains of Patagonia,
or when looking from the highest crest of the Cordilleras, the mind is
filled with the stupendous dimensions of the surrounding masses.