&c., form the food of the finches and other birds on their first arrival; and no sooner does the snow begin to thaw, forming a surface on the ice of the smaller lakes, than the larvæ of gnats, and other insects, swarm in myriads, affording abundant supplies of suitable food for the young birds, as soon as they are hatched. Other birds, such as the ptarmigan, feed on the catkins of the dwarf birch and willow, and may therefore obtain their food, even amidst the snow. These and other capabilities, cause a large number of birds to migrate to these northerly regions, yielding, in their turn, a supply of food to the human inhabitants of those barren and desolate lands.

The passenger pigeons, whose migrations in such immense bodies, as actually to obscure the light of day, render them an object of interest, feed chiefly on beech masts, and their migrations appear, in great measure, dependent on the abundance of that food. They migrate northwards towards the end of summer, as far as the 62nd parallel; and return southwards when the supplies fail them in those parts. Among the other birds of North America, are the Virginian owl (fig. 118), the mocking bird, and innumerable flocks of warblers, fly-catchers, starlings, thrushes, woodpeckers, &c., keeping the noxious insects within due bounds, and making the woods resound with their notes. The turkey (fig. 124) is a native of these regions, and still found wild in the woods.

The islands of North America are, from their high latitude, subject to great severity of climate, and their animal and vegetable productions are limited in number. Southampton Island, situated at the entrance of Hudson's Bay, presents a dreary appearance; the land being high and irregular, and the whole face of the country consisting of little else than rounded blocks of granite: the only trees are a few miserably stunted willows; and the only animals observed by Captain Back, were a brace of ptarmigans. The Georgian Islands possess an equally rigorous climate. Melville Island, the most westerly of the group, appears to be nearly desti

tute of animal and vegetable productions. Sir Edward Parry, during his stay in this region, met with no other animals than a few ptarmigans in the summer, and a pack of hungry wolves in the winter. A succession of islands, included in the same group, extends eastward from Melville Island, all bearing a similar Arctic character.

The remarkable vegetable, the Palmella nivalis, to which the appellation of "red snow " has been given, occurs abundantly in the islands of North America. This singular cryptogamic plant grows in situations where there is no land, no rock, no earth, to which it can attach itself; the snow forming its native station. Minute as is this little plant, it is as perfectly adapted for the situation it occupies, as is the most splendid tropical plant: it is formed from a seed, and provided with organs by means of which it imbibes nourishment from the atmosphere, and from the snow: it grows, bears seed, and decays; probably furnishing in its decay, soil for future generations of its own kind: and perhaps ultimately, for more important species. So abundant is this lichen in these high northern latitudes, that, in some parts, the snow has been found tinged with it to the depth of twelve feet, and the surface covered with it for many miles. We have already noticed its occurrence on the Alps of Europe.

Greenland, although its actual limits have not hitherto been ascertained, is evidently a territory of vast extent. Its aspect is very dreary, especially on the eastern coast, which is described as consisting, in most parts, of one almost uninterrupted glacier, varied only by a few patches of vegetation, principally occurring on the banks of the rivers, which, in their course to the ocean, dissolve the ice in their immediate vicinity. A mountain range skirts the shores in this part, forming-bold and precipitous cliffs, and rising in the interior into numberless peaks and cones, ranging from 2000 to 3000 feet in height; but the portion of the range known as the Werner Mountains, attains the elevation of 6000 feet above the sea. These shores are deeply indented by bays and

inlets. The south-western coast of Greenland, though apparently the most favoured portion of this arctic region, presents little to adapt it for the abode of civilized man. In this district, the only trees, if trees they can be called, consist of some low bushes of birch and willow, which never exceed two feet in height. A fine grass springs up in some parts, but withers quickly, when exposed to the warmth of the sun. Besides these plants, the vegetation chiefly consists of some species of cochlearia, sorrel, and a few other similar plants; one or two alpine flowers, and the ling, or common heath. It is a remarkable fact, that whilst not a single species of heath occurs in any part of America, the latter plant, so common in Europe, should also be met with in Greenland. The insects of Greenland, as we have already remarked, are likewise similar to those of the Old World. The larger animals consist only of the most northern species; and the seas abound in marine mammalia, which form the principal food of the natives.

CHAPTER XX.

GENERAL FEATURES OF SOUTH AMERICA. THE ANTARCTIC REGIONS.

Where the roots of the Andes

Strike deep in the earth:

As their summits to heaven

Shoot soaringly forth.-BYRON.

Two remarkable features characterize the vast peninsula of South America:—the colossal range of mountains, which traverse it from north to south; and the almost boundless plains, which occupy so large a portion of its eastern surface.

The Andes, called also the Cordilleras, or Chains of the Andes, present a mighty unbroken range of elevated sum

mits, rising, like a vast wall, on the western side of the continent, parallel to, and at no great distance from, the Pacific Ocean, and extending from the dreary regions of Tierra del Fuego, to the most northern boundaries of South America: being also remarkable for the numerous active volcanos, and the prodigious volcanic agency exhibited in nearly their whole course.

Tierra del Fuego consists of a group of islands of mountainous character, intersected by narrow and deep arms of the sea. The summits of these islands are crowned with perpetual snow; but their steep and rocky shores are in great part covered with evergreen woods, consisting chiefly of a species of evergreen beech, and of the winter's bark (fig. 6), both of which thrive in the sheltered parts of these islands, as far as 2000 feet above the sea level. The line of perpetual snow descends considerably lower in this region, than in parallel northern latitudes; and yet, vegetation appears to thrive so luxuriantly, that on these shores, the fuschia and veronica, which in our climate rank as tender plants, not only flourish in the open air, but attain the size of woody-stemmed trees, the stems being five or six inches in diameter: and they were observed by Captain King, in full flower, at the temperature of 36°, and growing at the base of a mountain, two-thirds of which was covered with snow. This circumstance has been attributed to the superior clearness of the atmosphere in this region. The parrot and humming bird extend their range to the Straits of Magelhaens; the former in quest of the seeds of the winter's bark, whilst the humming bird sips the honey from the blossoms of the fuschia, and has even been observed tering about in the midst of a snow shower.

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In their more southern parts, the Andes are not remarkable for their altitude; the average height being about 3000 feet, and the most elevated summit that has been measured to the south of the island of Chiloe, not exceeding 9000 feet above the sea. In this part, which may be distinguished as Western Patagonia, the mountains

border closely on the ocean, the waters reaching to their very base, and forming numerous inlets, resembling, though on a larger scale, the fiords of Norway; and the whole of the region off this coast presents the appearance of the upper portion of a mountain range, the base of which is immersed in the ocean, whilst its summits form multitudes of islands. These islands are barren to seaward, but towards the mainland they are clothed with impenetrable woods; and there are very few acres capable of cultivation in the whole district: no place fit for the permanent abode of civilized man. The large island of Chiloe is fertile, but like this portion of the coast, exposed, as we have already seen, to an excessive amount of wind and rain.

In the territory of Chili, the Andes do not border so closely on the ocean, between which and their base a belt of land occurs, varying in fertility, and becoming gradually less productive as it approaches the equator. Thus, the country in the vicinity of Concepcion, is covered with the richest and most luxuriant foliage; near Valparaiso, the hills are thinly clad with stunted brushwood, and a sprinkling of grass, the ground generally looking poor and bare; near Coquimbo the brushwood disappears, and nothing is met with but the cactus, and a few blades of gray or purple wiry grass, excepting indeed, during the rainy season, when beautiful annuals spring up: further northwards, all traces of vegetation cease, and sand hills and plains alone are seen, unless perhaps, in a few spots, where some stream of water, caused by the melting of the snow on the Andes, may fertilize the channel through which it takes its course.

The Andes, in this part, occasionally rise abruptly from the plains, with nearly perpendicular walls of sienite, 1000 feet in height. In those parts where the acclivities are less steep, the lower portion of the range is covered with lofty forest trees, which gradually diminish in size at increasing elevations, until they wholly disappear, and nothing but bare rocky masses are seen, or summits covered with perpetual snow. In the more northern parts of Chili, however,