dation to which they have been subjected. It is in this manner that hills composed of hard basalts and greenstones, alternating with soft tufas or stratified rocks, assume terraciform declivities; that extinct volcanic hills, like those of Auvergne, put on a crateriform aspect; that those largely composed of hard massive strata-as limestone, conglomerates, and sandstones-present a tabular appearance; and that mountains capped and flanked by crystalline schists are serrated with peaks and pinnacles.] 57. With these explanations, the principal MOUNTAIN-SYSTEMS, whose direction and extent will be best seen on reference to the Atlas, may be here enumerated--the student remembering that there is much in this arrangement that is arbitrary, or, at all events, not sufficiently established by actual observation. Thus, in EUROPE, geographers usually distinguish the British system, comprising the Grampians, Cheviot, Cumbrian, Cambrian, and Hibernian ranges; the Iberian or Spanish, embracing the Pyrenees, the Cantabrian Mountains, the Sierra Morena, Sierra Nevada, and the sierras of the central table-land; the Sardo-Corsican, consisting of the mountainous range of Sardinia and Corsica; the Alpine, including the Alps proper, Apennines, Carpathians, Balkan, and Hellenic ranges; the Scandinavian, or mountain plateaux of Norway and Sweden; the Sarmatian, or central high-ground of Russia; the Uralian, and Caucasian. In ASIA we have the Western system, comprising the Taurus, Anti-Taurus, Lebanon, Armenian, and Elburz ranges; the South-eastern system, embracing the Hindoo Koosh, the Himalaya, and the mountains of Birmah, Siam, and Cochin-China; the Eastern system, comprising the Kuen-lun, the Pe-ling, Yun-ling, Kihan-shan, In-shan, and other Chinese ranges; and the North-eastern system, extending from the Bolor Tagh in the centre of the continent to Behring Strait, and comprehending the Thian-shan, the Altai, Yablonoi, and Stannovoi ranges. In AFRICA may be enumerated the Atlas system; the Guinea system, embracing the Kong and Cameroon Mountains; and, so far as is known, the Eastern system, comprehending such as the Quotlamba, Lupata, and other contiguous ranges. In NORTH AMERICA, the Pacific system, embracing the great range of the Mexican Cordilleras and the Rocky Mountains, on the west of the continent; and the Atlantic or Appalachian system (Alleghanies, &c.) on the east. In SOUTH AMERICA there is the giant system of the Andes in the west, the Brazilian system in the east, and the system of Parimè between the rivers Amazon and Orinocco in the north. Of AUSTRALIA and its mountain-chains we know too little as yet to enable us to arrange them into groups or systems, though one main ridge, extending along the eastern coast from Torres Strait on the north to the extreme point of Tasmania on the south, would seem to indicate a sameness and continu ity of geological upheaval. Besides the above, other minor systems have been named; but enough has been indicated to lead the student to the appreciation of the fact that the principal mountainchains may be arranged in groups or systems that have arisen apparently from the same set of geological causes acting more or less continuously along the line or direction of their elevation. [Touching the general distribution of mountains, it has been aptly remarked by Sir John Herschel that, "In the New World we find a continuity of a vast and extremely precipitous line of very elevated mountains, running from the Arctic Ocean almost to the extremity of Patagonia (a distance of 8280 statute miles), skirting along the western coast of that immense continent, closely following all its flexures in the southern half, and in the northern opening out somewhat more, it is true, but still preserving the same general character of a lofty, mountainous, western border to a vast expanse of eastern lowlands; and, throughout the whole of this border, we perceive a most distinct and unmistakable tendency to a system of double or triple ridges, nearly or exactly parallel, not here and there for short distances, but extending for hundreds of miles in succession, and resumed again and again when interrupted. In the Old World, on the other hand, we find no single, well-defined, continuous chain running throughout, much less following the coast-line, but a broad belt of mountainous country traversing the whole mass of land in a general direction, and carried through the heart of the continents, from the extremity of Europe and North Africa across to the western shores of the Pacific. In the European portion of this system, linear prolongation, except in the Pyrenees, is very far from distinctly indicated. On the contrary, divarication and embranchment are there the dominant features, as they are especially so in the northwestern region of Asia; and it requires some determination in tracing connections to follow out a leading line through the Pyrenees, the higher Alps, the Caucasus, and the mountains of Elbrouz, through the Hindu Koh, up to the great system of Asiatic mountains which enclose the plateau of Thibet. Neither is the principle of parallel association carried out with anything like the same precision and sequence in the old as in the new continent. Along the Caucasian and Elbrouz range, and as far as the termination of the Hindu Koh, this principle is pretty clearly maintained; but from the point in Little Thibet where this last-mentioned system forks out into the two great chains of the Himalaya and Kuen Lun which euclose the table-land of Thibet proper, a greater degree of confusion and interlacement prevails, and beyond the termination of these ranges in Assam and on the Chinese frontier, the mountain-system of China and south-western Asia spreads out like an immense fan, in some of whose ranges a high degree of parallelism is preserved among contiguous members, while in others the branching character prevails quite as conspicuously."] 58. As mountain-systems exercise very decided influences on the natural history of the globe, and as they generally appear in ranges consisting either of one central chain with branches or spurs running off at right angles, or of several chains running less or more parallel to each other, various theories have been advanced to account for their upheaval, their parallelism, and their geographical connections. Thus, as their central masses generally consist of igneous rocks (compare Geological Map of Europe with Map of Mountainsystems), which have been protruded from below, and as this pro truding force must have acted along the line of least resistance in the crust, the question arises, What is the determining cause of these directions? According to Elie de Beaumont, the French geologist, every system of mountains occupies a portion of a great circle of the globe-a cleft or fissure being more easily made in that direction than in any other; and he shows that the mountainchains of the same age are parallel to one another even when in opposite hemispheres. Professor Hopkins of Cambridge, treating the subject from a purely mathematical point of view, has also shown that when the upheaving force acts on a single point, the lines of upheaval must radiate from that point; hence lofty central mountains with diverging spurs. He further shows that when the expansive force acts uniformly over a wide area, the lines of greatest tension or upheaval must be in the direction either of the length or of the breadth of the area, and that, if the crust yields in more places than one, the fissures would necessarily be parallel. Of course this uniformity of system has been considerably obscured, if not modified, by subsequent geological changes; and it must also be remembered that, whatever may give the initial direction to a mountain-range, its subsequent increase is ever more a matter of accumulation than of upheaval. European Systems. 59. Accepting such generalisations as initiatory steps towards the explanation of one of the most important problems connected with the history of our planet, we may now advert to the character of the mountain chains or ranges of which the preceding systems are respectively composed. Under the British system are embraced the Northern or Ross-shire range, the Grampians, the Cheviots, the Cumbrian or Cumberland mountains, the Cambrian or Welsh, the Devonian, and the Hibernian or Irish, all having less or more a south-west and north-east strike, and all belonging to the eastern or primary geological periods. Their geological structure-huge granitic bosses flanked and capped by the crystalline schists-confers on them considerable boldness and diversity of scenery, though their minor, elevation prevents that massive grandeur and ruggedness so often displayed by loftier ranges. None of them rise to the height of perpetual congelation (about 5000 feet for the centre of the British Islands); but in an insular and northern position such as that they occupy, their cold, heathclad, inhospitable summits exercise a decided influence alike on climate, scenery, and natural productions. Arranging them in tabular order, with their culminating heights or points of highest elevation, they appear as follows: Northern or Ross-shire range, Ben Attow, Cheviots, Pennine chain, Cumbrian or Cumberland range, Scaw Fell, Hibernian mountains, M'Gillicuddy's Reeks,. 4000 feet. دو 3166 29 3571 29 2077 "" 3410 "" 60. The Iberian or Hesperian system embraces the Pyrenees, Cantabrian Mountains, Mountains of Toledo, Sierra Morena, Sierra Nevada, and other associated elevations that give character to the rocky table-land and peninsula of Spain. Less ancient than the British system, but loftier in their altitude and more extensive in their ranges, they exercise a still more decided influence on the external condition of their region. Ranging chiefly in an east and west direction, and upheaving rocks of primary and secondary formation, rising, in many parts, above the line of perpetual snow (which ascends from 8000 feet in the Pyrenees to 11,000 feet in the Sierra Nevada), and being intersected by numerous deep defiles and narrow valleys, they create great diversity of scenery, climate, and production, and are of themselves the frequent storehouses of the minerals and metals. Arranged in tabular form, with their culminating points, they are as follows: 61. The Sardo-Corsican system, as its name implies, is confined to the islands of Sardinia and Corsica, and extends from Cape Jeulada in the former, to Cape Corso in the latter. It is a high, rugged, and irregular range, attaining its culminating point in Monte Rotondo, in Corsica, which rises to the height of 8767 feet-an elevation closely bordering on the line of perpetual snow, which in that latitude ascends to 9000 feet. In its geological bearings it is evidently connected with the Alpine development, and ought, properly speaking, to be regarded as a mere outlier of that gigantic system. 62. Under the Alpine system are usually comprehended the whole of those extensive and lofty mountains which, from Switzerland as a centre, ramify in ranges more or less persistent, and confer on southern Europe one of its most marked and peculiar features. These ranges have many minor subdivisions, but for our present purpose it will be enough to arrange them into the Western and Eastern Alps, which, under several local names (the Maritime, Cottian, Graian, Pennine, Helvetian, Bernese, Phætian, Carnic, Noric, and other Alps) extend in a north-east direction from the shores of the Mediterranean to the table-land of Bohemia ; the Gallo-Francian mountains, including the Jura, Vosges, and other contiguous French ranges; the Apennines, traversing the entire length of the Italian peninsula, and terminating in the still active volcano of Etna; the Slavo-Hellenic ranges, lying between the shores of the Adriatic and the plain of the Danube, and which stretch eastward into the Balkan chain on the one hand, and southward into the Pindus chain on the other; and, lastly, the long range of the Carpathians, Krapacks, or Hercynian Mountains, which rise between the plain of the Danube and the great plain of Europe, and mark the northern limits of the system. The component members of this grand Alpine system are of various geological ages, ranging from the granites and crystalline schists of the Western Alps, through the secondary limestones and altered shales of the Jura, down to the tertiary beds of the sub-Apennines and the recent lavas and scoria of Vesuvius and Etna. Connected with the older range of the Pyrenees on the west, and with the still active craters of Vesuvius, Etna, and the Lipari Islands on the east, the Alpine system may be said to have been on the increase from the earliest geologic times to the present moment-gaining accession after accession, and this even since the tertiary period, to much of the Auvergne, Apennine, and Hellenic ranges, and to the Alps themselves an additional altitude of not less, perhaps, than 4000 or 5000 feet. Being of different geological structures and altitudes, the different members of the system present great diversity of character and aspect. Rising in many places above the snow-line, which sinks from 9000 feet in the Alps to 6000 feet in the Carpathians, they are rugged with peak and precipice, glacier and narrow gorge, as in the Helvetian Alps; swelling and sloping in outline, as in the Apennines; crateriform and terraced, as in the hills of Auvergne ; rocky and precipitous, as in the Balkan and Pindus ranges; or rich in minerals, as in the mountains of Transylvania. With the exception of the plains of Bavaria and Bohemia, which lie on the very outskirts of the system, there are no table-lands, in the proper sense of the term, connected with the development-the whole being a true typical mountain-series of ridge and valley, peak and pass, beetling precipice and rugged ravine. Subjoined are the component ranges of the system, with their culminations or points of highest elevation : |