Strait of Magellan—Port Famine—Ascent of Mount Tarn—Forests—Edible
fungus—Zoology—Great Seaweed—Leave Tierra del Fuego—Climate—Fruit-trees
and productions of the southern coasts—Height of snow-line on the
Cordillera—Descent of glaciers to the sea—Icebergs formed—Transportal
of boulders—Climate and productions of the Antarctic
Islands—Preservation of frozen carcasses—Recapitulation.
STRAIT OF MAGELLAN.—CLIMATE OF THE SOUTHERN COASTS.
In the end of May 1834 we entered for a second time the eastern mouth
of the Strait of Magellan. The country on both sides of this part of
the Strait consists of nearly level plains, like those of Patagonia.
Cape Negro, a little within the second Narrows, may be considered as
the point where the land begins to assume the marked features of Tierra
del Fuego. On the east coast, south of the Strait, broken park-like
scenery in a like manner connects these two countries, which are
opposed to each other in almost every feature. It is truly surprising
to find in a space of twenty miles such a change in the landscape. If
we take a rather greater distance, as between Port Famine and
Gregory Bay, that is about sixty miles, the difference is still more
wonderful. At the former place we have rounded mountains concealed by
impervious forests, which are drenched with the rain brought by an
endless succession of gales; while at Cape Gregory there is a clear and
bright blue sky over the dry and sterile plains. The atmospheric
currents,[1] although rapid, turbulent, and unconfined by any apparent
limits, yet seem to follow, like a river in its bed, a regularly
determined course.
[1] The south-westerly breezes are generally very dry. January 29th,
being at anchor under Cape Gregory: a very hard gale from west by
south, clear sky with few cumuli; temperature 57°, dew-point
36°,—difference 21°. On January 15th, at Port St. Julian: in the
morning light winds with much rain, followed by a very heavy squall
with rain,—settled into heavy gale with large cumuli,—cleared up,
blowing very strong from south-south-west. Temperature 60°, dew-point
42°,—difference 18°.
Patagonians from Cape Gregory
During our previous visit (in January), we had an interview at Cape
Gregory with the famous so-called gigantic Patagonians, who gave us a
cordial reception. Their height appears greater than it really is, from
their large guanaco mantles, their long flowing hair, and general
figure: on an average their height is about six feet, with some men
taller and only a few shorter; and the women are also tall; altogether
they are certainly the tallest race which we anywhere saw. In features
they strikingly
resemble the more northern Indians whom I saw with Rosas, but they have
a wilder and more formidable appearance: their faces were much painted
with red and black, and one man was ringed and dotted with white like a
Fuegian. Captain Fitz Roy offered to take any three of them on board,
and all seemed determined to be of the three. It was long before we
could clear the boat; at last we got on board with our three giants,
who dined with the Captain, and behaved quite like gentlemen, helping
themselves with knives, forks, and spoons: nothing was so much relished
as sugar. This tribe has had so much communication with sealers and
whalers, that most of the men can speak a little English and Spanish;
and they are half civilised, and proportionally demoralised.
Port Famine, Magellan
The next morning a large party went on shore, to barter for skins and
ostrich-feathers; fire-arms being refused, tobacco was in greatest
request, far more so than axes or tools. The whole population of the
toldos, men, women, and children, were arranged on a bank. It was an
amusing scene, and it was impossible not to
like the so-called giants, they were so thoroughly good-humoured and
unsuspecting: they asked us to come again. They seem to like to have
Europeans to live with them; and old Maria, an important woman in the
tribe, once begged Mr. Low to leave any one of his sailors with them.
They spend the greater part of the year here; but in summer they hunt
along the foot of the Cordillera: sometimes they travel as far as the
Rio Negro, 750 miles to the north. They are well stocked with horses,
each man having, according to Mr. Low, six or seven, and all the women,
and even children, their one own horse. In the time of Sarmiento (1580)
these Indians had bows and arrows, now long since disused; they then
also possessed some horses. This is a very curious fact, showing the
extraordinarily rapid multiplication of horses in South America. The
horse was first landed at Buenos Ayres in 1537, and the colony being
then for a time deserted, the horse ran wild;[2] in 1580, only
forty-three years afterwards, we hear of them at the Strait of
Magellan! Mr. Low informs me, that a neighbouring tribe of foot-Indians
is now changing into horse-Indians: the tribe at Gregory Bay giving
them their worn-out horses, and sending in winter a few of their best
skilled men to hunt for them.
[2] Rengger, _Natur. der Saeugethiere von Paraguay._ S. 334.
_June_ 1_st._—We anchored in the fine bay of Port Famine. It was now
the beginning of winter, and I never saw a more cheerless prospect; the
dusky woods, piebald with snow, could be only seen indistinctly through
a drizzling hazy atmosphere. We were, however, lucky in getting two
fine days. On one of these, Mount Sarmiento, a distant mountain 6800
feet high, presented a very noble spectacle. I was frequently
surprised, in the scenery of Tierra del Fuego, at the little apparent
elevation of mountains really lofty. I suspect it is owing to a cause
which would not at first be imagined, namely, that the whole mass, from
the summit to the water’s edge, is generally in full view. I remember
having seen a mountain, first from the Beagle Channel, where the whole
sweep from the summit to the base was full in view, and then from
Ponsonby Sound across several successive ridges; and it was curious to
observe in the latter case, as each fresh ridge afforded fresh means of
judging of the distance, how the mountain rose in height.
Before reaching Port Famine, two men were seen running along the shore
and hailing the ship. A boat was sent for them.
They turned out to be two sailors who had run away from a
sealing-vessel, and had joined the Patagonians. These Indians had
treated them with their usual disinterested hospitality. They had
parted company through accident, and were then proceeding to Port
Famine in hopes of finding some ship. I daresay they were worthless
vagabonds, but I never saw more miserable-looking ones. They had been
living for some days on mussel-shells and berries, and their tattered
clothes had been burnt by sleeping so near their fires. They had been
exposed night and day, without any shelter, to the late incessant
gales, with rain, sleet, and snow, and yet they were in good health.
[Illustration]
During our stay at Port Famine, the Fuegians twice came and plagued us.
As there were many instruments, clothes, and men on shore, it was
thought necessary to frighten them away. The first time a few great
guns were fired, when they were far distant. It was most ludicrous to
watch through a glass the Indians, as often as the shot struck the
water, take up stones, and, as a bold defiance, throw them towards the
ship, though about a mile and a half distant! A boat was then sent with
orders to fire a few musket-shots wide of them. The Fuegians hid
themselves behind the trees, and for every discharge of the muskets
they fired their arrows; all, however, fell short of the boat, and the
officer as he pointed at them laughed. This made the Fuegians frantic
with passion, and they shook their mantles in vain rage. At last,
seeing the balls cut and strike the trees, they ran away, and we were
left in peace and quietness. During the former voyage the Fuegians were
here very troublesome, and to frighten them a rocket was fired at night
over their wigwams; it answered effectually, and one of the officers
told me that the clamour first raised, and the barking of the dogs, was
quite ludicrous in contrast with the profound silence which in a minute
or two afterwards prevailed. The next morning not a single Fuegian was
in the neighbourhood.
Patagonian spurs and pipe
When the _Beagle_ was here in the month of February, I started one
morning at four o’clock to ascend Mount Tarn, which is 2600 feet high,
and is the most elevated point in this immediate district. We went in a
boat to the foot of the mountain (but unluckily not to the best part),
and then began our ascent. The forest commences at the line of
high-water mark, and during the first two hours I gave over all hopes
of reaching the summit. So thick was the wood, that it was necessary to
have constant recourse to the compass; for every landmark, though in a
mountainous country, was completely shut out. In the deep ravines the
death-like scene of desolation exceeded all description; outside it was
blowing a gale, but in these hollows not even a breath of wind stirred
the leaves of the tallest trees. So gloomy, cold, and wet was every
part, that not even the fungi, mosses, or ferns could flourish. In the
valleys it was scarcely possible to crawl along, they were so
completely barricaded by great mouldering trunks, which had fallen down
in every direction. When passing over these natural bridges, one’s
course was often arrested by sinking knee deep into the rotten wood; at
other times, when attempting to lean against a firm tree, one was
startled by finding a mass of decayed matter ready to fall at the
slightest touch. We at last found ourselves among the stunted trees,
and then soon reached the bare ridge, which conducted us to the summit.
Here was a view characteristic of Tierra del Fuego; irregular chains of
hills, mottled with patches
of snow, deep yellowish-green valleys, and arms of the sea intersecting
the land in many directions. The strong wind was piercingly cold, and
the atmosphere rather hazy, so that we did not stay long on the top of
the mountain. Our descent was not quite so laborious as our ascent, for
the weight of the body forced a passage, and all the slips and falls
were in the right direction.
I have already mentioned the sombre and dull character of the evergreen
forests,[3] in which two or three species of trees grow, to the
exclusion of all others. Above the forest land there are many dwarf
alpine plants, which all spring from the mass of peat, and help to
compose it: these plants are very remarkable from their close alliance
with the species growing on the mountains of Europe, though so many
thousand miles distant. The central part of Tierra del Fuego, where the
clay-slate formation occurs, is most favourable to the growth of trees;
on the outer coast the poorer granitic soil, and a situation more
exposed to the violent winds, do not allow of their attaining any great
size. Near Port Famine I have seen more large trees than anywhere else:
I measured a Winter’s Bark which was four feet six inches in girth, and
several of the beech were as much as thirteen feet. Captain King also
mentions a beech which was seven feet in diameter seventeen feet above
the roots.
[3] Captain Fitz Roy informs me that in April (our October) the leaves
of those trees which grow near the base of the mountains change
colour, but not those on the more elevated parts. I remember having
read some observations, showing that in England the leaves fall
earlier in a warm and fine autumn than in a late and cold one. The
change in the colour being here retarded in the more elevated, and
therefore colder situations, must be owing to the same general law of
vegetation. The trees of Tierra del Fuego during no part of the year
entirely shed their leaves.
[Illustration]
There is one vegetable production deserving notice from its importance
as an article of food to the Fuegians. It is a globular, bright-yellow
fungus, which grows in vast numbers on the beech-trees. When young it
is elastic and turgid, with a smooth surface; but when mature, it
shrinks, becomes tougher, and has its entire surface deeply pitted or
honeycombed, as represented in the figure at right. This fungus belongs
to a new and curious genus;[4] I found a second
species on another species of beech in Chile: and Dr. Hooker informs me
that just lately a third species has been discovered on a third species
of beech in Van Diemen’s Land. How singular is this relationship
between parasitical fungi and the trees on which they grow, in distant
parts of the world! In Tierra del Fuego the fungus in its tough and
mature state is collected in large quantities by the women and
children, and is eaten uncooked. It has a mucilaginous, slightly sweet
taste, with a faint smell like that of a mushroom. With the exception
of a few berries, chiefly of a dwarf arbutus, the natives eat no
vegetable food besides this fungus. In New Zealand, before the
introduction of the potato, the roots of the fern were largely
consumed; at the present time, I believe, Tierra del Fuego is the only
country in the world where a cryptogamic plant affords a staple article
of food.
[4] Described from my specimens and notes by the Reverend J. M.
Berkeley in the _Linnean Transactions_ (vol. xix, p. 37), under the
name of Cyttaria Darwinii: the Chilean species is the C. Berteroii.
This genus is allied to Bulgaria.
The zoology of Tierra del Fuego, as might have been expected from the
nature of its climate and vegetation, is very poor. Of mammalia,
besides whales and seals, there is one bat, a kind of mouse (Reithrodon
chinchilloides), two true mice, a ctenomys allied to or identical with
the tucutuco, two foxes (Canis Magellanicus and C. Azaræ), a sea-otter,
the guanaco, and a deer. Most of these animals inhabit only the drier
eastern parts of the country; and the deer has never been seen south of
the Strait of Magellan. Observing the general correspondence of the
cliffs of soft sandstone, mud, and shingle, on the opposite sides of
the Strait, and on some intervening islands, one is strongly tempted to
believe that the land was once joined, and thus allowed animals so
delicate and helpless as the tucutuco and Reithrodon to pass over. The
correspondence of the cliffs is far from proving any junction; because
such cliffs generally are formed by the intersection of sloping
deposits, which, before the elevation of the land, had been accumulated
near the then existing shores. It is, however, a remarkable
coincidence, that in the two large islands cut off by the Beagle
Channel from the rest of Tierra del Fuego, one has cliffs composed of
matter that may be called stratified alluvium, which front similar ones
on the opposite side of the
channel,—while the other is exclusively bordered by old crystalline
rocks; in the former, called Navarin Island, both foxes and guanacos
occur; but in the latter, Hoste Island, although similar in every
respect, and only separated by a channel a little more than half a mile
wide, I have the word of Jemmy Button for saying that neither of these
animals is found.
The gloomy woods are inhabited by few birds: occasionally the plaintive
note of a white-tufted tyrant-flycatcher (Myiobius albiceps) may be
heard, concealed near the summit of the most lofty trees; and more
rarely the loud strange cry of a black woodpecker, with a fine scarlet
crest on its head. A little, dusky-coloured wren (Scytalopus
Magellanicus) hops in a skulking manner among the entangled mass of the
fallen and decaying trunks. But the creeper (Oxyurus tupinieri) is the
commonest bird in the country. Throughout the beech forests, high up
and low down, in the most gloomy, wet, and impenetrable ravines, it may
be met with. This little bird no doubt appears more numerous than it
really is, from its habit of following with seeming curiosity any
person who enters these silent woods: continually uttering a harsh
twitter, it flutters from tree to tree, within a few feet of the
intruder’s face. It is far from wishing for the modest concealment of
the true creeper (Certhia familiaris); nor does it, like that bird, run
up the trunks of trees, but industriously, after the manner of a
willow-wren, hops about, and searches for insects on every twig and
branch. In the more open parts, three or four species of finches, a
thrush, a starling (or Icterus), two Opetiorhynchi, and several hawks
and owls occur.
The absence of any species whatever in the whole class of Reptiles is a
marked feature in the zoology of this country, as well as in that of
the Falkland Islands. I do not ground this statement merely on my own
observation, but I heard it from the Spanish inhabitants of the latter
place, and from Jemmy Button with regard to Tierra del Fuego. On the
banks of the Santa Cruz, in 50 degrees south, I saw a frog; and it is
not improbable that these animals, as well as lizards, may be found as
far south as the Strait of Magellan, where the country retains the
character of Patagonia; but within the damp and cold limit of Tierra
del Fuego not one occurs. That the climate would not have
suited some of the orders, such as lizards, might have been foreseen;
but with respect to frogs, this was not so obvious.
Beetles occur in very small numbers: it was long before I could believe
that a country as large as Scotland, covered with vegetable productions
and with a variety of stations, could be so unproductive. The few which
I found were alpine species (Harpalidæ and Heteromidæ) living under
stones. The vegetable-feeding Chrysomelidæ, so eminently characteristic
of the Tropics, are here almost entirely absent;[5] I saw very few
flies, butterflies, or bees, and no crickets or Orthoptera. In the
pools of water I found but few aquatic beetles, and not any fresh-water
shells: Succinea at first appears an exception; but here it must be
called a terrestrial shell, for it lives on the damp herbage far from
water. Land-shells could be procured only in the same alpine situations
with the beetles. I have already contrasted the climate as well as the
general appearance of Tierra del Fuego with that of Patagonia; and the
difference is strongly exemplified in the entomology. I do not believe
they have one species in common; certainly the general character of the
insects is widely different.
[5] I believe I must except one alpine Haltica, and a single specimen
of a Melasoma. Mr. Waterhouse informs me, that of the Harpalidæ there
are eight or nine species—the forms of the greater number being very
peculiar; of Heteromera, four or five species; of Rhyncophora, six or
seven; and of the following families one species in each:
Staphylinidæ, Elateridæ, Cebrionidæ, Melolonthidæ. The species in the
other orders are even fewer. In all the orders, the scarcity of the
individuals is even more remarkable than that of the species. Most of
the Coleoptera have been carefully described by Mr. Waterhouse in the
_Annals of Nat. Hist._
If we turn from the land to the sea, we shall find the latter as
abundantly stocked with living creatures as the former is poorly so. In
all parts of the world a rocky and partially protected shore perhaps
supports, in a given space, a greater number of individual animals than
any other station. There is one marine production which, from its
importance, is worthy of a particular history. It is the kelp, or
Macrocystis pyrifera. This plant grows on every rock from low-water
mark to a great depth, both on the outer coast and within the
channels.[6] I
believe, during the voyages of the _Adventure_ and _ Beagle_, not one
rock near the surface was discovered which was not buoyed by this
floating weed. The good service it thus affords to vessels navigating
near this stormy land is evident; and it certainly has saved many a one
from being wrecked. I know few things more surprising than to see this
plant growing and flourishing amidst those great breakers of the
western ocean, which no mass of rock, let it be ever so hard, can long
resist. The stem is round, slimy, and smooth, and seldom has a diameter
of so much as an inch. A few taken together are sufficiently strong to
support the weight of the large loose stones, to which in the inland
channels they grow attached; and yet some of these stones were so heavy
that when drawn to the surface, they could scarcely be lifted into a
boat by one person. Captain Cook, in his second voyage, says that this
plant at Kerguelen Land rises from a greater depth than twenty-four
fathoms; “and as it does not grow in a perpendicular direction, but
makes a very acute angle with the bottom, and much of it afterwards
spreads many fathoms on the surface of the sea, I am well warranted to
say that some of it grows to the length of sixty fathoms and upwards.”
I do not suppose the stem of any other plant attains so great a length
as three hundred and sixty feet, as stated by Captain Cook. Captain
Fitz Roy, moreover, found it growing[7] up from the greater depth of
forty-five fathoms. The beds of this sea-weed, even when of not great
breadth, make excellent natural floating breakwaters. It is quite
curious to see, in an exposed harbour, how soon the waves from the open
sea, as they travel through the straggling stems, sink in height, and
pass into smooth water.
[6] Its geographical range is remarkably wide; it is found from the
extreme southern islets near Cape Horn, as far north on the eastern
coast (according to information given me by Mr. Stokes) as lat.
43°,—but on the western coast, as Dr. Hooker tells me, it extends to
the R. San Francisco in California, and perhaps even to Kamtschatka.
We thus have an immense range in latitude; and as Cook, who must have
been well acquainted with the species, found it at Kerguelen Land, no
less than 140° in longitude.
[7] _Voyages of the Adventure and Beagle_, vol. i, p. 363. It appears
that seaweed grows extremely quick. Mr. Stephenson found (Wilson’s
_Voyage round Scotland_ vol. ii, p. 228) that a rock uncovered only at
spring-tides, which had been chiselled smooth in November, on the
following May, that is, within six months afterwards, was thickly
covered with Fucus digitatus two feet, and F. esculentus six feet, in
length.
The number of living creatures of all Orders, whose existence
intimately depends on the kelp, is wonderful. A great volume might be
written, describing the inhabitants of one of these beds of seaweed.
Almost all the leaves, excepting those that float on the surface, are
so thickly incrusted with corallines as
to be of a white colour. We find exquisitely delicate structures, some
inhabited by simple hydra-like polypi, others by more organised kinds,
and beautiful compound Ascidiæ. On the leaves, also, various
patelliform shells, Trochi, uncovered molluscs, and some bivalves are
attached. Innumerable crustacea frequent every part of the plant. On
shaking the great entangled roots, a pile of small fish, shells,
cuttlefish, crabs of all orders, sea-eggs, starfish, beautiful
Holothuriæ, Planariæ, and crawling nereidous animals of a multitude of
forms, all fall out together. Often as I recurred to a branch of the
kelp, I never failed to discover animals of new and curious structures.
In Chiloe, where the kelp does not thrive very well, the numerous
shells, corallines, and crustacea are absent; but there yet remain a
few of the Flustraceæ, and some compound Ascidiæ; the latter, however,
are of different species from those in Tierra del Fuego; we see here
the fucus possessing a wider range than the animals which use it as an
abode. I can only compare these great aquatic forests of the southern
hemisphere with the terrestrial ones in the intertropical regions. Yet
if in any country a forest was destroyed, I do not believe nearly so
many species of animals would perish as would here, from the
destruction of the kelp. Amidst the leaves of this plant numerous
species of fish live, which nowhere else could find food or shelter;
with their destruction the many cormorants and other fishing birds, the
otters, seals, and porpoises, would soon perish also; and lastly, the
Fuegian savage, the miserable lord of this miserable land, would
redouble his cannibal feast, decrease in numbers, and perhaps cease to
exist.
_June_ 8_th._—We weighed anchor early in the morning and left Port
Famine. Captain Fitz Roy determined to leave the Strait of Magellan by
the Magdalen Channel, which had not long been discovered. Our course
lay due south, down that gloomy passage which I have before alluded to
as appearing to lead to another and worse world. The wind was fair, but
the atmosphere was very thick; so that we missed much curious scenery.
The dark ragged clouds were rapidly driven over the mountains, from
their summits nearly down to their bases. The glimpses which we caught
through the dusky mass were highly interesting; jagged points, cones of
snow, blue glaciers, strong outlines, marked on a lurid sky, were seen
at different distances and
heights. In the midst of such scenery we anchored at Cape Turn, close
to Mount Sarmiento, which was then hidden in the clouds. At the base of
the lofty and almost perpendicular sides of our little cove there was
one deserted wigwam, and it alone reminded us that man sometimes
wandered into these desolate regions. But it would be difficult to
imagine a scene where he seemed to have fewer claims or less authority.
The inanimate works of nature—rock, ice, snow, wind, and water, all
warring with each other, yet combined against man—here reigned in
absolute sovereignty.
_June_ 9_th._—In the morning we were delighted by seeing the veil of
mist gradually rise from Sarmiento, and display it to our view. This
mountain, which is one of the highest in Tierra del Fuego, has an
altitude of 6800 feet. Its base, for about an eighth of its total
height, is clothed by dusky woods, and above this a field of snow
extends to the summit. These vast piles of snow, which never melt, and
seem destined to last as long as the world holds together, present a
noble and even sublime spectacle. The outline of the mountain was
admirably clear and defined. Owing to the abundance of light reflected
from the white and glittering surface, no shadows were cast on any
part; and those lines which intersected the sky could alone be
distinguished: hence the mass stood out in the boldest relief. Several
glaciers descended in a winding course from the upper great expanse of
snow to the sea-coast: they may be likened to great frozen Niagaras;
and perhaps these cataracts of blue ice are full as beautiful as the
moving ones of water. By night we reached the western part of the
channel; but the water was so deep that no anchorage could be found. We
were in consequence obliged to stand off and on in this narrow arm of
the sea, during a pitch-dark night of fourteen hours long.
_June_ 10_th._—In the morning we made the best of our way into the open
Pacific. The western coast generally consists of low, rounded, quite
barren hills of granite and greenstone. Sir J. Narborough called one
part South Desolation, because it is “so desolate a land to behold:”
and well indeed might he say so. Outside the main islands there are
numberless scattered rocks on which the long swell of the open ocean
incessantly rages. We passed out between the East and West Furies;
and a little farther northward there are so many breakers that the sea
is called the Milky Way. One sight of such a coast is enough to make a
landsman dream for a week about shipwrecks, peril, and death; and with
this sight we bade farewell for ever to Tierra del Fuego.
The following discussion on the climate of the southern parts of the
continent with relation to its productions, on the snow-line, on the
extraordinarily low descent of the glaciers, and on the zone of
perpetual congelation in the antarctic islands, may be passed over by
any one not interested in these curious subjects, or the final
recapitulation alone may be read. I shall, however, here give only an
abstract, and must refer for details to the Thirteenth Chapter and the
Appendix of the former edition of this work.
_On the Climate and Productions of Tierra del Fuego and of the
South-west Coast._—The following table gives the mean temperature of
Tierra del Fuego, the Falkland Islands, and, for comparison, that of
Dublin:—
Summer Winter Mean of Summer
Latitude. Temp. Temp. and Winter.
Tierra del Fuego 53° 38′ S. 50° 33.08° 41.54°
Falkland Islands 51° 30′ S. 51° — —
Dublin 53° 21′ N. 59.54° 39.20° 49.37°
Hence we see that the central part of Tierra del Fuego is colder in
winter, and no less than 9.5° less hot in summer, than Dublin.
According to von Buch the mean temperature of July (not the hottest
month in the year) at Saltenfiord in Norway, is as high as 57.8°, and
this place is actually 13° nearer the pole than Port Famine![8]
Inhospitable as this climate appears to our feelings, evergreen trees
flourish luxuriantly under it. Humming-birds may be seen sucking the
flowers, and parrots feeding on the seeds of the Winter’s Bark, in
latitude 55 degrees south. I have already remarked to what a degree the
sea swarms with living creatures; and the shells
(such as the Patellæ, Fissurellæ, Chitons, and Barnacles), according to
Mr. G. B. Sowerby, are of a much larger size, and of a more vigorous
growth, than the analogous species in the northern hemisphere. A large
Voluta is abundant in southern Tierra del Fuego and the Falkland
Islands. At Bahia Blanca, in lat. 39° S., the most abundant shells were
three species of Oliva (one of large size), one or two Volutas, and a
Terebra. Now these are amongst the best characterised tropical forms.
It is doubtful whether even one small species of Oliva exists on the
southern shores of Europe, and there are no species of the two other
genera. If a geologist were to find in lat. 39° on the coast of
Portugal a bed containing numerous shells belonging to three species of
Oliva, to a Voluta, and Terebra, he would probably assert that the
climate at the period of their existence must have been tropical; but,
judging from South America, such an inference might be erroneous.
[8] With respect to Tierra del Fuego, the results are deduced from the
observations of Capt. King (_Geographical Journal_, 1830), and those
taken on board the _Beagle._ For the Falkland Islands, I am indebted
to Captain Sulivan for the mean of the mean temperature (reduced from
careful observation at midnight, 8 A.M., noon, and 8 P.M.) of the
three hottest months, namely, December, January, and February. The
temperature of Dublin is taken from Barton.
The equable, humid, and windy climate of Tierra del Fuego extends, with
only a small increase of heat, for many degrees along the west coast of
the continent. The forests for 600 miles northward of Cape Horn, have a
very similar aspect. As a proof of the equable climate, even for 300 or
400 miles still farther northward, I may mention that in Chiloe
(corresponding in latitude with the northern parts of Spain) the peach
seldom produces fruit, whilst strawberries and apples thrive to
perfection. Even the crops of barley and wheat[9] are often brought
into the houses to be dried and ripened. At Valdivia (in the same
latitude of 40° with Madrid) grapes and figs ripen, but are not common;
olives seldom ripen even partially, and oranges not at all. These
fruits, in corresponding latitudes in Europe, are well known to succeed
to perfection; and even in this continent, at the Rio Negro, under
nearly the same parallel with Valdivia, sweet potatoes (convolvulus)
are cultivated; and grapes, figs, olives, oranges, water and musk
melons, produce abundant fruit. Although the humid and equable climate
of Chiloe, and of the coast northward and southward of it, is so
unfavourable to our fruits, yet the native forests, from lat. 45° to
38°, almost rival in luxuriance those of the glowing intertropical
regions. Stately trees of many kinds, with smooth and highly coloured
barks, are loaded by parasitical monocotyledonous
plants; large and elegant ferns are numerous, and arborescent grasses
entwine the trees into one entangled mass to the height of thirty or
forty feet above the ground. Palm-trees grow in latitude 37°; an
arborescent grass, very like a bamboo, in 40°; and another closely
allied kind, of great length, but not erect, flourishes even as far
south as 45° S.
[9] Agüeros, _Descrip. Hist. de la Prov. de Chiloé_, 1791, p. 94.
An equable climate, evidently due to the large area of sea compared
with the land, seems to extend over the greater part of the southern
hemisphere; and as a consequence, the vegetation partakes of a
semi-tropical character. Tree-ferns thrive luxuriantly in Van Diemen’s
Land (lat. 45°), and I measured one trunk no less than six feet in
circumference. An arborescent fern was found by Forster in New Zealand
in 46°, where orchideous plants are parasitical on the trees. In the
Auckland Islands, ferns, according to Dr. Dieffenbach,[10] have trunks
so thick and high that they may be almost called tree-ferns; and in
these islands, and even as far south as lat. 55° in the Macquarie
Islands, parrots abound.
[10] See the German Translation of this Journal; and for the other
facts Mr. Brown’s Appendix to Flinders’s _ Voyage._
_On the Height of the Snow-line, and on the Descent of the Glaciers, in
South America._—For the detailed authorities for the following table, I
must refer to the former edition:—
Latitude. Height in feet Observer
of Snow-line
Equatorial region: mean result 15,748 Humboldt.
Bolivia, lat. 16° to 18° S. 17,000 Pentland.
Central Chile, lat. 33° S. 14,500 to 15,000 Gillies, and the Author.
Chiloe, lat. 41° to 43° S. 6000 Officers of the Beagle and the Author.
Tierra del Fuego, 54° S. 3500 to 4000 King.
As the height of the plane of perpetual snow seems chiefly to be
determined by the extreme heat of the summer, rather than by the mean
temperature of the year, we ought not to be surprised at its descent in
the Strait of Magellan, where the summer is so cool, to only 3500 or
4000 feet above the level of the sea; although in Norway, we must
travel to between lat. 67° and 70° N., that is, about 14° nearer the
pole, to meet with perpetual snow at this low level. The difference in
height, namely, about 9000 feet, between the snow-line on the
Cordillera behind Chiloe (with its highest points ranging from
only 5600 to 7500 feet) and in central Chile[11] (a distance of only 9°
of latitude), is truly wonderful. The land from the southward of Chiloe
to near Concepcion (lat. 37°) is hidden by one dense forest dripping
with moisture. The sky is cloudy, and we have seen how badly the fruits
of southern Europe succeed. In central Chile, on the other hand, a
little northward of Concepcion, the sky is generally clear, rain does
not fall for the seven summer months, and southern European fruits
succeed admirably; and even the sugar-cane has been cultivated.[12] No
doubt the plane of perpetual snow undergoes the above remarkable
flexure of 9000 feet, unparalleled in other parts of the world, not far
from the latitude of Concepcion, where the land ceases to be covered
with forest-trees; for trees in South America indicate a rainy climate,
and rain a clouded sky and little heat in summer.
[11] On the Cordillera of central Chile, I believe the snow-line
varies exceedingly in height in different summers. I was assured that
during one very dry and long summer, all the snow disappeared from
Aconcagua, although it attains the prodigious height of 23,000 feet.
It is probable that much of the snow at these great heights is
evaporated, rather than thawed.
[12] Miers’s _Chile_, vol. i, p. 415. It is said that the sugar-cane
grew at Ingenio, lat. 32° to 33°, but not in sufficient quantity to
make the manufacture profitable. In the valley of Quillota, south of
Ingenio, I saw some large date-palm trees.
Eyre Sound
The descent of glaciers to the sea must, I conceive, mainly depend
(subject, of course, to a proper supply of snow in the upper region) on
the lowness of the line of perpetual snow on steep mountains near the
coast. As the snow-line is so low in Tierra del Fuego, we might have
expected that many of the glaciers would have reached the sea.
Nevertheless I was astonished when I first saw a range, only from 3000
to 4000 feet in height, in the latitude of Cumberland, with every
valley filled with streams of ice descending to the sea-coast. Almost
every arm of the sea, which penetrates to the interior higher chain,
not only in Tierra del Fuego, but on the coast for 650 miles
northwards, is terminated by “tremendous and astonishing glaciers,” as
described by one of the officers on the survey. Great masses of ice
frequently fall from these icy cliffs, and the crash reverberates like
the broadside of a man-of-war through the lonely channels. These falls,
as noticed in the last chapter, produce great waves which break on the
adjoining coasts. It is known that earthquakes frequently cause masses
of earth to fall from sea-cliffs: how terrific, then, would be the
effect of a severe shock (and such occur here[13]) on a body like a
glacier, already in motion, and traversed by fissures! I can readily
believe that the water would be fairly beaten back out of the deepest
channel, and then, returning with an overwhelming force, would whirl
about huge masses of rock like so much chaff. In Eyre’s Sound, in the
latitude of Paris, there are immense glaciers, and yet the loftiest
neighbouring mountain is only 6200 feet high. In this Sound, about
fifty icebergs were seen at one time floating outwards, and one of them
must have been _at least_ 168 feet in total height. Some of the
icebergs were loaded with blocks of no inconsiderable size, of granite
and other rocks, different from the clay-slate of the surrounding
mountains. The glacier farthest from the Pole, surveyed during the
voyages of the _Adventure_ and _Beagle_, is in lat. 46° 50′, in the
Gulf of Penas. It is 15 miles long, and in one part 7 broad, and
descends to the sea-coast. But even a few miles northward of this
glacier, in the Laguna de San Rafael, some Spanish missionaries[14]
encountered “many icebergs, some great, some small, and others
middle-sized,” in a narrow arm of the sea, on the 22nd of the month
corresponding with our
June, and in a latitude corresponding with that of the Lake of Geneva!
[13] Bulkeley’s and Cummin’s _Faithful Narrative of the Loss of the
Wager._ The earthquake happened August 25, 1741.
[14] Agüeros, _Desc. Hist. de Chiloé_, p. 227.
Glacier in Gulf of Penas
In Europe, the most southern glacier which comes down to the sea is met
with, according to Von Buch, on the coast of Norway, in lat. 67°. Now,
this is more than 20° of latitude, or 1230 miles, nearer the pole than
the Laguna de San Rafael. The position of the glaciers at this place
and in the Gulf of Penas may be put even in a more striking point of
view, for they descend to the sea-coast within 7½° degrees of latitude,
or 450 miles, of a harbour, where three species of Oliva, a Voluta, and
a Terebra, are the commonest shells, within less than 9° from where
palms grow, within 4½° of a region where the jaguar and puma range over
the plains, less than 2½° from arborescent grasses, and (looking to the
westward in the same hemisphere) less than 2° from orchideous
parasites, and within a single degree of tree-ferns!
These facts are of high geological interest with respect to the climate
of the northern hemisphere, at the period when boulders were
transported. I will not here detail how simply the theory of icebergs
being charged with fragments of rock explains the origin and position
of the gigantic boulders of eastern Tierra del Fuego, on the high plain
of Santa Cruz, and on the island of Chiloe. In Tierra del Fuego the
greater number of boulders lie on the lines of old sea-channels, now
converted into dry valleys by the elevation of the land. They are
associated with a great unstratified formation of mud and sand,
containing rounded and angular fragments of all sizes, which has
originated[15] in the repeated ploughing up of the sea-bottom by the
stranding of icebergs, and by the matter transported on them. Few
geologists now doubt that those erratic boulders which lie near lofty
mountains have been pushed forward by the glaciers themselves, and that
those distant from mountains, and embedded in subaqueous deposits, have
been conveyed thither either on icebergs, or frozen in coast-ice. The
connection between the transportal of boulders and the presence of ice
in some form, is strikingly shown by their geographical distribution
over the earth. In South America they are not found farther than 48° of
latitude, measured from the southern pole; in North America it appears
that the limit of their transportal extends to 53½° from the northern
pole; but in Europe to not more than 40° of latitude, measured from the
same point. On the other hand, in the intertropical parts of America,
Asia, and Africa, they have never been observed; nor at the Cape of
Good Hope, nor in Australia.[16]
[15] _Geological Transactions_, vol. vi, p. 415.
[16] I have given details (the first, I believe, published) on this
subject in the first edition, and in the Appendix to it. I have there
shown that the apparent exceptions to the absence of erratic boulders
in certain hot countries are due to erroneous observations; several
statements there given I have since found confirmed by various
authors.
_On the Climate and Productions of the Antarctic Islands._—Considering
the rankness of the vegetation in Tierra del Fuego, and on the coast
northward of it, the condition of the islands south and south-west of
America is truly surprising. Sandwich Land, in the latitude of the
north part of Scotland, was found by Cook, during the hottest month of
the year, “covered many fathoms thick with everlasting snow;” and there
seems to be scarcely any vegetation. Georgia, an island 96 miles long
and 10 broad, in the latitude of Yorkshire, “in the very height of
summer, is in a manner wholly covered with frozen snow.” It can boast
only of moss, some tufts of grass, and wild burnet; it has only one
land-bird (Anthus correndera), yet Iceland, which is 10° nearer the
pole, has, according to Mackenzie, fifteen land-birds. The South
Shetland Islands, in the same latitude as the southern half of Norway,
possess only some lichens, moss, and a little grass; and Lieut.
Kendall[17] found the bay in which he was at anchor, beginning to
freeze at a period corresponding with our 8th of September. The soil
here consists of ice and volcanic ashes interstratified; and at a
little depth beneath the surface it must remain perpetually congealed,
for Lieut. Kendall found the body of a foreign sailor which had long
been buried, with the flesh and all the features perfectly preserved.
It is a singular fact that on the two great continents in the northern
hemisphere (but not in the broken land of Europe between them) we have
the zone of perpetually frozen under-soil in a low latitude—namely, in
56 degrees in North America at the depth of three feet,[18] and in 62°
in Siberia at the depth of twelve to fifteen feet—as the result of a
directly opposite condition of things to those of the southern
hemisphere. On the northern continents, the winter is rendered
excessively cold by the radiation from a large area of land into a
clear sky, nor is it moderated by the warmth-bringing currents of the
sea; the short summer, on the other hand, is hot. In the Southern Ocean
the winter is not so excessively cold, but the summer is far less hot,
for the clouded sky seldom allows the sun to warm the ocean, itself a
bad absorbent of heat: and hence the mean temperature of the year,
which regulates the zone of perpetually congealed under-soil, is low.
It is evident that a rank vegetation, which does not so much require
heat as it does protection from intense cold, would approach much
nearer to this zone of perpetual congelation under the equable climate
of the southern hemisphere, than under the extreme climate of the
northern continents.
[17] _Geographical Journal_, 1830, pp. 65, 66.
[18] Richardson’s _Append. to Back’s Exped._ and Humboldt’s _ Fragm.
Asiat._ tome ii, p. 386.
[Illustration]
The case of the sailor’s body perfectly preserved in the icy soil of
the South Shetland Islands (lat. 62° to 63° S.), in a rather lower
latitude than that (lat. 64° N.) under which Pallas found the frozen
rhinoceros in Siberia, is very interesting. Although it is a fallacy,
as I have endeavoured to show in a former chapter, to suppose that the
larger quadrupeds require a luxuriant vegetation for their support,
nevertheless it is important to find in the South Shetland Islands a
frozen under-soil within 360 miles of the forest-clad islands near Cape
Horn, where, as far as the _ bulk_ of vegetation is concerned, any
number of great quadrupeds might be supported. The perfect preservation
of the carcasses of the Siberian elephants and rhinoceroses is
certainly one of the most wonderful facts in geology; but independently
of the imagined difficulty of supplying them with food from the
adjoining countries, the whole case is not, I think, so perplexing as
it has generally been considered. The plains of Siberia, like those of
the Pampas, appear to have been formed under the sea, into which rivers
brought down the bodies of many animals; of the greater number of these
only the skeletons have been preserved, but of others the perfect
carcass. Now it is known that in the shallow sea on the Arctic coast of
America the bottom freezes,[19] and does not thaw in spring so soon as
the surface
of the land, moreover, at greater depths, where the bottom of the sea
does not freeze, the mud a few feet beneath the top layer might remain
even in summer below 32°, as is the case on the land with the soil at
the depth of a few feet. At still greater depths the temperature of the
mud and water would probably not be low enough to preserve the flesh;
and hence, carcasses drifted beyond the shallow parts near an arctic
coast, would have only their skeletons preserved: now in the extreme
northern parts of Siberia bones are infinitely numerous, so that even
islets are said to be almost composed of them;[20] and those islets lie
no less than ten degrees of latitude north of the place where Pallas
found the frozen rhinoceros. On the other hand, a carcass washed by a
flood into a shallow part of the Arctic Sea, would be preserved for an
indefinite period, if it were soon afterwards covered with mud
sufficiently thick to prevent the heat of the summer water penetrating
to it; and if, when the sea-bottom was upraised into land, the covering
was sufficiently thick to prevent the heat of the summer air and sun
thawing and corrupting it.
[19] Messrs. Dease and Simpson, in _Geographical Journal_ vol. viii,
pp. 218 and 220.
[20] Cuvier (_Ossemens Fossiles,_ tome i, p. 151), from Billing’s
_Voyage._
_Recapitulation._—I will recapitulate the principal facts with regard
to the climate, ice-action, and organic productions of the southern
hemisphere, transposing the places in imagination to Europe, with which
we are so much better acquainted. Then, near Lisbon, the commonest
sea-shells, namely, three species of Oliva, a Voluta, and a Terebra,
would have a tropical character. In the southern provinces of France,
magnificent forests, intwined by arborescent grasses and with the trees
loaded with parasitical plants, would hide the face of the land. The
puma and the jaguar would haunt the Pyrenees. In the latitude of Mont
Blanc, but on an island as far westward as Central North America,
tree-ferns and parasitical Orchideæ would thrive amidst the thick
woods. Even as far north as central Denmark humming-birds would be seen
fluttering about delicate flowers, and parrots feeding amidst the
evergreen woods; and in the sea there we should have a Voluta, and all
the shells of large size and vigorous growth. Nevertheless, on some
islands only 360 miles northward of our new Cape Horn in Denmark, a
carcass buried in the soil (or if washed into a shallow sea, and
covered up with mud) would be preserved perpetually frozen. If some
bold navigator attempted to penetrate northward of these islands, he
would run a thousand dangers amidst gigantic icebergs, on some of which
he would see great blocks of rock borne far away from their original
site. Another island of large size in the latitude of southern
Scotland, but twice as far to the west, would be “almost wholly covered
with everlasting snow,” and would have each bay terminated by
ice-cliffs, whence great masses would be yearly detached: this island
would boast only of a little moss, grass, and burnet, and a titlark
would be its only land inhabitant. From our new Cape Horn in Denmark, a
chain of mountains, scarcely half the height of the Alps, would run in
a straight line due southward; and on its western flank every deep
creek of the sea, or fiord, would end in “bold and astonishing
glaciers.” These lonely channels would frequently reverberate with the
falls of ice, and so often would great waves rush along their coasts;
numerous icebergs, some as tall as cathedrals, and occasionally loaded
with “no inconsiderable blocks of rock,” would be stranded on the
outlying islets; at intervals violent earthquakes would shoot
prodigious masses of ice into the waters below. Lastly, some
missionaries
attempting to penetrate a long arm of the sea, would behold the not
lofty surrounding mountains, sending down their many grand icy streams
to the sea-coast, and their progress in the boats would be checked by
the innumerable floating icebergs, some small and some great; and this
would have occurred on our twenty-second of June, and where the Lake of
Geneva is now spread out![21]
[21] In the former edition and Appendix, I have given some facts on
the transportal of erratic boulders and icebergs in the Antarctic
Ocean. This subject has lately been treated excellently by Mr. Hayes,
in the _Boston Journal_ (vol. iv, p. 426). The author does not appear
aware of a case published by me (_Geographical Journal_, vol. ix, p.
528), of a gigantic boulder embedded in an iceberg in the Antarctic
Ocean, almost certainly one hundred miles distant from any land, and
perhaps much more distant. In the Appendix I have discussed at length
the probability (at that time hardly thought of) of icebergs, when
stranded, grooving and polishing rocks, like glaciers. This is now a
very commonly received opinion; and I cannot still avoid the suspicion
that it is applicable even to such cases as that of the Jura. Dr.
Richardson has assured me that the icebergs off North America push
before them pebbles and sand, and leave the submarine rocky flats
quite bare; it is hardly possible to doubt that such ledges must be
polished and scored in the direction of the set of the prevailing
currents. Since writing that Appendix I have seen in North Wales
(_London Phil. Mag._ vol. xxi, p. 180) the adjoining action of
glaciers and floating icebergs.
[Illustration]
[Illustration: Trochilus Forficatus]