HOW BOULDERS ARE TRANSPORTED TO GREAT HEIGHTS.
Sir Roderick Murchison has shown that in Russia, when the Dwina is at its maximum height, and penetrates into the chinks of its limestone banks, when frozen and expanded it causes disruptions of the rock, the entanglement of stony fragments in the ice. In remarkable spring floods, the stream so expands that in bursting it throws up its icy fragments to 15 or 20 feet above the stream; and the waters subsiding, these lateral ice-heaps melt away, and leave upon the bank the rifled and angular blocks as evidence of the highest ice-mark. In Lapland, M. Böhtlingk assures us that he has found large granitic boulders weighing several tons actually entangled and suspended, like birds’-nests, in the branches of pine-trees, at heights of 30 or 40 feet above the summer level of the stream![28]