225.] The plains-loving Magyars of Hungary have pushed up to the rim of mountainous Siebenburgen or Transylvania from Arad on the Maros River to Sziget on the upper Theiss, while the highland region has a predominant Roumanian population.  A clearly defined linguistic and cultural boundary of Indo-Aryan speech and religion, both Hindu and Mohammedan, follows the piedmont edges of the Brahmaputra Valley, and separates the lowland inhabitants from the pagans of Tibeto-Burman speech occupying the Himalayan slope to the north and the Khasia Mountains to the south.  The highland race is Mongoloid, while the Bengali of an Aryan, Dravidian and Mongoloid blend fill the river plain.[1192] Such piedmont boundary lines tend to blur into bands or zones of ethnic intermixture and cultural assimilation.  The western Himalayan foothills show the blend of Mongoloid and Aryan stocks, where the vigorous Rajputs of the plains have encroached upon the mountaineer’s land.[1193] Of almost every mountain folk it can be assumed that they once occupied their highlands to the outermost rim of the piedmont, and retired to the inner rim of this intermediary slope only under compulsion from without.

[Sidenote:  Density of population in piedmont belts.]

The piedmont boundary also divides two areas of contrasted density of population.  Mountain regions are, as a rule, more sparsely settled than plains.  The piedmont is normally a transition region in this respect; but where high mountains rise as climatic islands of adequate water supply out of desert and steppes, they concentrate on their lower slopes all the sedentary population, making their piedmonts zones of greatest density.  Low mountains in arid regions become centers of population; here their barrier nature vanishes.  In the Sudanese state of Darfur, the Marra Mountains are the district best watered and most thickly populated.  Nowhere higher than 6000 feet (1850 meters), they afford running water at 4000 feet elevation and water pools in the sandy beds of their wadis at 3200 feet.  Below this, water disappears from the surface, and can be found only in wells whose depth and scarcity increase with distance from the central mountains.[1194] The neighboring kingdom of Wadai shows similar conditions and effects.[1195] In the heart of Australia, where utter desert reigns, the Macdonnell Ranges form the nucleus of the northern area occupied by the Arunta tribe of natives; farther north the Murchison Range, usually abounding in water-holes, is the center and stronghold of the Warramunga tribe.[1196]

Mineral wealth or waterpower in the mountains serves to collect an urban and industrial population along their rim, as we see it about the base of the Erz Mountains in Saxony, the Riesen range in Silesia, the coal-bearing Pennine Mountains of northwestern England, and the highlands of southern Wales, all which piedmont zones show a density of over 150 to the square kilometer (385 to the square mile).  Hence the original Swiss Confederation, which included only the mountain cantons of Schwyz, Uri and Unterwalden, was greatly strengthened by the accession of the piedmont cantons of Lucerne, Zurich, Zug and Bern in the early fourteenth century, as later by St. Gall, Aargau and Geneva.  These marginal cantons to-day show a density of population exceeding 385 to the square mile, and rising to 1356 in the canton of Geneva.