|two feet, aM F. esculentus six fe-et, in length.
240 TIERRA DEL FUEGO. [chap. xi.
greater depth of forty-five fathoms. The beds o£ 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 Ascidias. 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, starfish, beautiful Holuthurise, 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 nc\ thrive very well, the numerous shells, corallines. and crustacea are absent; but there yet remain a few of the Flustracese, and some compound Ascidise ; the latter, however, are of different species from those in Tierra del Fuego: we here see 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.
1834.] MOUNT SARMIENTO. 241
June 8th.—We weighed anchor early in the morning and left Port Famine. Capfain 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
242 CLIMATE AND PRODUCTIONS OF [chap. xi.
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 \Oth.~-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 snowline, 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 :—•
T ... , 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 21N. 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^° less hot in summer, than Dublin. According to Yon 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
1834.] TIERRA DEL FUEGO AND THE WEST COAST. 243
the pole than Port Famine!* Inhospitable as this climate appears to our feelings, evergreen trees flourish luxuriantly under it. Humming-birds maybe seen sucking the flowers, and parrots feeding on the seeds of the Winter's Bark, in lat. 55° S. I have already remarked to what a degree the sea swarms with living creatures; and the shells (such as the Patellse, Fissurellse, 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 Yolutas, 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.
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 j- are often brought iiito 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
* With respect to Tierra del Fuego, the results are deduced from the observations by Capt. King (Geographical Journal, 1830), and those taken on board the Beagle. For the Falkland Islands, I am indebted to Capt. Salivan 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 mouthy viz. December, January, ana February. The temperature of Dublin is taken from Barton.
f Agüeros, Descríp. Hist, de la Prov. de Chiloe, 1791, p. 94.
244 HEIGHT OF SNOW-LIisTE. [chap. xi.
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 lat. 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.
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 orchi-deous plants are parasitical on the trees. In the Auckland Islands, ferns, according to Dr. Dieffenbach,* 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 Mac-quarrie 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:—
T ... j Height in feet ^
Latitude. of Snow-line. Observer.
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. . . 6,000 Officers of the Beagle, and the Author.
Tierra del Fuego, 54° S. . . 3,500 to 4,000 King.
As the height of the plane of perpetual snow seems chiefly to
* See the German Translation of this Journal: and for the other facts Mr. Brown's Appendix to Flinders's Voyage.
1834.] DESCENT OF GLACIEKS. 245
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* (a distance of only 9* of latitude), is truly wonderful. The land from the southward of Chiloe to near Concepción (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 Concepción, 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.")" 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 Concepción, 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
* 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.
f 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 largo date palm-trees.
246 FLOATING ICEBERGS. [chap. xr.
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*) 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
* Bulkeley*s and Cummin's Faithful Narrative of the Loss of the Wager The earthquake happened August 25, 1741.
1834.] ERRATIC BOULDERS. 247
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° 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* 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 Yon 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 Hafael. 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^° 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 4 J° of a region where the jaguar and puma range over the plains, less than 2J° 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 unstrati-fied formation of mud and sand, containing rounded and angular fragments of all sizes, which has originated "f in the repeated
* Agüeros, Desc. Hist, de Chiloe, p. 227. f Geological Transactions, vol. vi. p. 415.