Page:Popular Science Monthly Volume 14.djvu/103

Rh of both, and legitimately conclude that the agency in each case was the same.

And let us select the Alps, as the first field for our explorations, renowned for the phalanx of illustrious minds who have studied this subject there, and famous as embracing those districts where the presence of traveled blocks first aroused inquiry, and their significance gave birth to the theory we are testing.

The Alps cover with their various arms, encircling ranges and subordinate elevations, all Switzerland; her lakes are nestled within their valleys, her rivers spring from their frigid slopes, her cities rest upon the débris of their attrition, while the strange and romantic loveliness which surrounds their fields of ice cover it as with a garment of imperishable beauty. The Alps are the result of gigantic upheavals, probably conducted through ages, which succeeded each other throughout the Tertiary age, and were continental in their extent. The Pyrenees, the Julian Alps, the Balkans, the Apennines, and Corsica, were elevated in this series of vast perturbations, a long range of towering mountains whose influence upon physical and social development has been as marked as the revolution it signalized in the world's topography.Europe, which had worn the flora of America, then lost it, and the sassafras, liriodendron, maple, and magnolia, failing to survive the climatic changes which intervened, yielded before the gradual growth of distinctively European species.

The Alps, after passing up along the eastern boundary of Piedmont, irregularly in long, deep bends and winding arches, run east and west, gathering upon their flanks innumerable lesser ranges, and knots of mountains, or in places subdividing into new and splendid lines of peaks which, diverging to the north, afterward unite with the parent chain or melt into the plain of Germany, through successive steps. A great congeries of intermingling and twisting ranges communicates the original disturbance over Switzerland, and the radiate lines of agitation may be traced southward upon the plains of Piedmont, through the Apennines into Italy, and by the Illyrian Alps into Dalmatia. The Alps inclose valleys and plateaus; their highest summits are scored by deep gulches which descend their sides; and broad crevices, ravines, and passes, ramify along their slopes. Into these troughs, far above the snow-line, fed by confluent furrows, the snows of winter have collected, and heaped up layer upon layer accumulated to great depths. The water of the melted surface percolating through these subjacent films, an increasing pressure has solidified them to a semi-icy state. Slowly in these deep fields of snow, by pressure, by alternate thawing and melting, the molecular condition of the mass undergoes a change, and becomes compacted into crystalline ice. Before this change is consummated, the mass of snow, ice, and congealing water, is called the nève. Thus formed, there emerge from these upper reservoirs vast sheets of ice which pass down between cliffs and crags, winding over