Influences of Geographic Environment - Ellen Churchill Semple (libby ebook reader .TXT) 📗
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If the historical movement slackens its pace at the piedmont slope, higher up the mountain it comes to a halt. Only when human invention has greatly improved communication across the barrier are its obstacles in part overcome. The great highland wall stretching across southern Europe from the Bay of Biscay to the Black Sea long cut off the solid mass of the continent from the culture of the Mediterranean lands. Owing to these mountains Central Europe came late into the foreground of history, not till the Middle Ages. Even the penetrating civilization of Greece reached it only by long detours around the ends of the mountain barrier; by Massilia and the Rhone, by Istria and the Danube, Greek commerce trickled through to the interior of the continent.
Where mountains fail to check, they deflect the historical movement. The wall of the Carpathians, bulwark of Central Europe, split the westward moving Slav hordes in the 6th century, diverting one southward up the Danube Valley to the Eastern Alps, and turning one northward along the German lowlands.1211 The northward expansion of the Romans, rebuffed by the high double wall of the Central Alps, was bent to the westward over the Maritime, Cottine and Savoy Alps, where the barrier offered the shortest and easiest transmontane routes. Hence Germany received the elements of Mediterranean culture indirectly through Gaul, second-hand and late. The ancient Helvetians, moving southward from northern Switzerland into Gaul, took a route skirting the western base of the Alps by the gap at Geneva, and thus threatened Roman Provincia. Cæsar's campaigns into northern Gaul were given direction by the massive Central Plateau of France.1212 The rugged and infertile area of the Catskills long retarded the westward movement in colonial New York and deflected it northward through the Mohawk depression, which therefore had its long thin line of settlements when the neighboring Catskills were still a "bare spot."
In their valleys, mountains lose something of their barrier nature, and approximate the level of the plains. Here they harbor oases of denser population and easier intercourse. Valleys favor human settlement through the milder climate of their lower elevation, the accumulation of soil on their floors, their sheltered environment, and their command of such routes of communication as the highlands afford. They are the avenues into and within a mountain system, and therefore radically influence its history by their direction and location. The Central Plateau of France, through the valleys of the Alliers and upper Loire, is most accessible from the north; therefore in that direction it has maintained its most important historical connections,1213 from the days of Cæsar and Vercingetorix. The massive highland region of Transylvania, which opens long accessible valleys westward toward the plains of the Theiss and Danube, has since the eleventh century received thence Hungarian immigration and political dominion.1214 Its dominant Roumanian population, however, seems to have fled thither from the Tartar-swept plains to the southeast.
The anthropo-geography of mountain valleys depends upon the structure of the highlands themselves, whether they are fold mountains, whose ranges wall in longitudinal valleys, or dissected plateaus, whose valleys are mostly transverse river channels leading from the hydrographic center out to the rim of the highlands. Longitudinal valleys are not only long, but also broad as a rule and often show a nearly level floor.1215 They therefore form districts of considerable size, fertility, and individuality, and play distinct historical rôles in the history of their respective highlands. Such are the upper Rhone Valley with its long line of flourishing towns and villages, the Hither Rhine, the Inn of the Tyrol and the Engadine, the fertile trough of the meandering Isère above Grenoble,1216 the broad Orontes-Leontes valley between the Lebanon and Anti-Lebanon where Kadesh and Baalbec were once the glory of northern Syria. Such is the central trough of the Appalachian Mountains, known as the Great Appalachian Valley, seventy-five miles wide, subdivided into constituent valleys of similar character by parallel, even-crested ridges following the trend of the mountains. These are drained by broad, leisurely rivers, bordered by fertile farms and substantial towns. Transverse valleys, on the other hand, are generally narrow, with steep slopes rising almost from the river's edge and supporting only small villages and farms. A comparison of the spacious, smooth-floored valley of Andermatt with the wild Reuss gorge, of the fertile and populous Shenandoah Valley in the Southern Appalachians with the canon of the Kanawha in the Cumberland Plateau, makes the contrast striking enough.
Longitudinal valleys, by reason of their length and their branching lateral valleys, are the natural avenues of communication within the mountains themselves. They therefore give a dominant direction to such phases of the historical movement as succeed in passing the outer barrier. The series of parallel ranges which strike off from the eastern end of the Tibetan plateau southward into Farther India have directed along their valleys the main streams of Mongolian migration and expansion, heading them toward the river basins of Burma and Indo China, and away from India itself.1217 While Tibetan elements have during the ages slowly welled over the high Himalayan brim and trickled down toward the Gangetic plain, Burma has been deluged by floods of Mongolians pouring down the runnels of the land. A carriage road follows the axis of the Central Alps from Lake Geneva to Lake Constance by means of the upper Rhone, Andermatt, and upper Rhine valleys, linked by the Furca and Oberalp passes. The Roman and Medieval routes northward across the Central Alps struck the upper Rhine Valley above Coire, (the ancient Curia Rhaetorum); this natural groove gave them a northeastward direction, and made them emerge from the mountains directly south of Ulm, which thereby gained great importance. The trade routes from Damascus and Palmyra which once entered the Orontes-Leontes trough in the Lebanon system found their Mediterranean termini south near Tyre or north near Antioch, and thus contributed to the greatness of those ancient emporiums. The Great Appalachian Valley used to be a highway for the Iroquois Indians, when they took the warpath against the Cherokee tribes of Tennessee. Later it gave a distinct southwestward trend to pioneer movements of population within the mountains, blending in its common channel the Quakers, Germans and Scotch-Irish from Pennsylvania, with the English and Huguenot French of the more southern colonies. In the Civil War its fertile fields were swept by marching armies, all the way from Chattanooga to Gettysburg.
The barrier nature of mountains depends upon their height and structure, whether they are massive, unbroken walls like the Scandinavian Alps and the Great Smoky range; or, like the Welsh Highlands and the Blue Ridge, are studded with low passes. The Pyrenees, Caucasus and Andes, owing to the scarcity and great height of their passes, have always been serious barriers. The Pyrenees divide Spain from France more sharply than the Alps divide Italy from France; owing to their rampart character, they form the best and most definite natural boundary in Europe.1218 Epirus and Aetolia, fenced in by the solid Pindus range, took little part in the common life of ancient Greece; but the intermittent chains of Thessaly offered a passway between Macedon and Hellas. The Alps have an astonishing number of excellent passes, evenly distributed for the most part. These, in conjunction with the great longitudinal valleys of the system, offer transit routes from side to side in any direction. The Appalachian system is some three hundred miles broad and thirteen hundred miles long, but it has many easy gaps among its parallel ranges, so that it offered natural though circuitous highways to the early winners of the West. The long line (400 miles) of the Hindu Kush range, high as it is, forms no strong natural boundary to India, because it is riddled with passes at altitudes from 12,500 to 19,000 feet.1219 The easternmost group of these passes lead down to Kashmir, and therefore lend this state peculiar importance as guardian of these northern entrances to India.1220 The Suleiman Mountains along the Indo-Afghan frontier are an imperfect defence for the same reason. They are indented by 289 passes capable of being traversed by camels. The mountain border of Baluchistan contains 75 more, the most important of which focus their roads upon Kandahar. Hence the importance to British India of Kandahar and Afghanistan. Across this broken northwest barrier have come almost all the floods of invasion and immigration that have contributed their varied elements to the mixed population of India. Tradition, epic and history tell of Asiatic highlanders ever sweeping down into the warm valley of the Indus through these passes; Scythians, Aryans, Greeks, Assyrians, Medes, Persians, Turks, Tartars, and Mongols have all traveled these rocky roads, to rest in the enervating valleys of the peninsula.1221
Mountains folded into a succession of parallel ranges are greater obstructions than a single range like the Erz, Black Forest, and Vosges, or a narrow, compact system like the Western Alps, which can be crossed by a single pass. Owing to this simple structure the Western Alps were traversed by four established routes in the days of the Roman Empire. These were: I. The Via Aurelia between the Maritime Alps and the sea, where now runs the Cornice Road. II. The Mons Matrona (Mont Genevre Pass, 6080 feet or 1854 meters [Transcriber's Note: printer's error incorrectly printed as kilometers]) between the headstream of the Dora Riparia and that of the Durance, which was the best highway for armies. III. The Little St. Bernard (7075 feet or 2157 meters), from Aosta on the Dora Baltea over to the Isère and down to Lugdunum (Lyons). IV. The Great St. Bernard (8109 feet or 2472 meters) route, which led northward from Aosta over the Pennine Alps to Octodurus at the elbow of the upper Rhone, where Martigny now stands. Across the broad double rampart of the Central Alps the Roman used chiefly the Brenner route, which by a low saddle unites the deep reëntrant valleys of the Adige and Inn rivers, and thus surmounts the barrier by a single pass. However, a short cut northward over the Chalk Alps by the Fern Pass made closer connection with Augusta Vindelicorum (Augsburg). The Romans seem to have been ignorant of the St. Gotthard, which, though high, is the summit of an unbroken ascent from Lake Maggiore up the valley of the Ticino on one side, and from Lake Lucerne up the Reuss on the other.
Mountains which spread out on a broad base in a series of parallel chains, and through which no long transverse valleys offer ready transit, form serious barriers to every phase of intercourse. The lofty boundary wall of the Pyrenees, a folded mountain system of sharp ranges and difficult passes, has successfully separated Spain from continental Europe; it has given the Iberian Peninsula, in the
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