Page:Popular Science Monthly Volume 9.djvu/567

Rh we advanced that the rocks became more and more worn and rounded; that in sheltered places, along the sides of the valley, beds of thick plastic clay were to be found; and also that the whole valley was strewed with smoothed and rounded pebbles, together with huge bowlders, many of which were a hundred tons in weight. These were often planed off and grooved, precisely like many of the transported stones that are scattered so plentifully over the hills and valleys of the State of New York; and like them, too, frequently differed in the nature of their material from the rocks of the surrounding cliffs. As we ascended the valley, these peculiarities became more and more strongly marked; while around us the hills and knolls had a rounded and flowing outline, and formed what are known as roches moutonnées, the mountain-peaks that towered above were sharp and angular, and stood out against the clear sky like cathedral-spires.

All these facts have such a marked and intimate connection with the glaciers that still linger on the mountain-side, that no one—who had traversed those valleys, or traced the streams up to the ice-caves, from which many of them spring, turbid and overloaded with silt, at the foot of the glaciers—could doubt that these valleys, with all their peculiar features, owe their existence to the great extension of the glaciers, which in past time flowed from the mountains in great rivers of ice, and carved out those grand valleys to a depth of many thousands of feet in the solid rock. As these ancient glaciers retreated and melted away, they left the indisputable records of their presence throughout the valley.

The same connection of rounded and striated bowlders (called Fündlinge—wandering children—by the German peasants) with existing glaciers has been observed by Agassiz and others in the Alps of Switzerland. Not only these facts, but the manner in which the glaciers flow down the valleys like great rivers of ice, has been closely observed and measured; they have been seen time and again transporting immense amounts of dirt and stones on their surface, which in time formed part of the terminal moraines at their extremity. The sides and bottoms of the valleys through which they flow are smoothed and covered with scratches made by the pebbles and stones set in the bottom and sides of the glacier, which in their turn were rounded and scratched, often in various directions, caused by their breaking from their matrix, and being reset in a new position.

If we were to place the rounded and scratched stones from the drift ("hard-pan," "hog's-backs," etc.) of New York beside the similar stones broken from their icy fastenings in the bottom of the glacier of Zermatt, we should find them so similar in their markings that no eye could distinguish but that they had made the journey under the glacier side by side.

If we compare the smoothed and striated rocks from the bottoms and shores of Lake Erie, Cayuga Lake, or almost any of our lakes