STRAIT OF MAGELLAN.--CLIMATE OF THE SOUTHERN COASTS
Strait of Magellan--Port Famine--Ascent of Mount Tarn--Forests--Edible
Fungus--Zoology--Great Sea-weed--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.
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.
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 civilized, and
proportionally demoralized.
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.
June 1st.--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 dare say 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.
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 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.
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.
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
[picture]
a smooth surface; but when mature it shrinks, becomes tougher, and has
its entire surface deeply pitted or honey-combed, as represented in the
accompanying woodcut. 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 Diernan'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 un-cooked. 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.
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. Azarae), 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 are 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 wood-pecker, 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 degs. 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 (Harpalidae and Heteromidae) living
under stones. The vegetable-feeding Chrysomelidae, 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 a 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 the 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.
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.
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 sea-weed.
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 organized kinds, and beautiful
compound Ascidiae. 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, cuttle-fish, crabs of
all orders, sea-eggs, star-fish, beautiful Holuthuriae, Planariae, 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
Flustraceae, and some compound Ascidiae; 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 8th.--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 9th.--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 10th.--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 38' S. 51 -- --
Dublin 53 21' N. 59.54 39.2 49.37
Hence we see that the central part of Tierra del Fuego is colder in
winter, and no less than 9.5 degs. 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 degs.,
and this place is actually 13 degs. 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
lat. 55 degs. S. I have already remarked to what a degree the sea
swarms with living creatures; and the shells (such as the Patellae,
Fissurellae, 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 degs. 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 characterized 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 degs. 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.
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 further 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 degs., 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 degs., 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 lat 37 degs.; an
arborescent grass, very like a bamboo, in 40 degs.; and another closely
allied kind, of great length, but not erect, flourishes even as far
south as 45 degs. S.
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 degs.), and I measured one trunk no less than six feet in
circumference. An arborescent fern was found by Forster in New Zealand
in 46 degs., 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 degs. in the
Macquarrie Islands, parrots abound.
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:--
Height in feet
Latitude of Snow-line Observer
----------------------------------------------------------------
Equatorial region; mean result 15,748 Humboldt. Bolivia,
lat. 16 to 18 degs. S. 17,000 Pentland. Central Chile,
lat. 33 degs. S. 14,500 - 15,000 Gillies, and
the Author.
Chiloe, lat. 41 to 43 degs. S. 6,000 Officers of the
Beagle and the
Author.
Tierra del Fuego, 54 degs. S. 3,500 - 4,000 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 degs. N., that is, about 14 degs.
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
degs. of latitude), is truly wonderful. The land from the southward of
Chiloe to near Concepcion (lat. 37 degs.) 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.
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 furthest from the pole, surveyed during the voyages of the
Adventure and Beagle, is in lat. 46 degs. 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 Laguna
de San
[picture]
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!
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 degs.
Now, this is more than 20 degs. 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 7.5 degs. 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
degs. from where palms grow, within 4.5 degs. of a region where the
jaguar and puma range over the plains, less than 2.5 degs. from
arborescent grasses, and (looking to the westward in the same
hemisphere) less than 2 degs. 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, explain 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 further than 48
degs. of latitude, measured from the southern pole; in North America it
appears that the limit of their transportal extends to 53.5 degs. from
the northern pole; but in Europe to not more than 40 degs. 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]
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 degs. 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 degs. in North America at the depth of three
feet, [18] and in 62 degs. 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.
The case of the sailor's body perfectly preserved in the icy soil of
the South Shetland Islands (lat. 62 to 63 degs. S.), in a rather lower
latitude than that (lat. 64 degs. 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 degs., as in
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.
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 Orchideae 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]
[1] The south-westerly breezes are generally very dry. January 29th,
being at anchor under Cape Gregory: a very hard gale from W. by S.,
clear sky with few cumuli; temperature 57 degs., dew-point 36
degs.,--difference 21 degs. 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 S.S.W. Temperature 60 degs., dew-point 42
degs.,--difference 18 degs.
[2] Rengger, Natur. der Saeugethiere von Paraguay. S. 334.
[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.
[4] Described from my specimens and notes by the Rev. 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.
[5] I believe I must except one alpine Haltica, and a single specimen
of a Melasoma. Mr. Waterhouse informs me, that of the Harpalidae 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:
Staphylinidae, Elateridae, Cebrionidae, Melolonthidae. 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.
[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
degs.,--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 degs. in longitude.
[7] Voyages of the Adventure and Beagle, vol. i. p. 363.--It appears
that sea-weed 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.
[8] With regard 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
Capt. Sulivan for the mean of the mean temperature (reduced from
careful observations at midnight, 8 A.M., noon, and 8 P.M.) of the
three hottest months, viz., December, January, and February. The
temperature of Dublin is taken from Barton.
[9] Agueros, Descrip. Hist. de la Prov. de Chiloe, 1791, p. 94.
[10] See the German Translation of this Journal; and for the other
facts, Mr. Brown's Appendix to Flinders's Voyage.
[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 degs., 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.
[13] Bulkeley's and Cummin's Faithful Narrative of the Loss of the
Wager. The earthquake happened August 25, 1741.
[14] Agueros, Desc. Hist. de Chiloe, p. 227.
[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 countries, are due to erroneous observations; several
statements there given I have since found confirmed by various authors.
[17] Geographical Journal, 1830, pp. 65, 66.
[18] Richardson's Append. to Back's Exped., and Humboldt's Fragm.
Asiat., tom. ii. p. 386.
[19] Messrs. Dease and Simpson, in Geograph. Journ., vol. viii. pp. 218
and 220.
[20] Cuvier (Ossemens Fossiles, tom. i. p. 151), from Billing's Voyage.
[21] In the former edition and Appendix, I have given some facts on the
transportal of erratic boulders and icebergs in the Atlantic 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.