[6] The Travels of Saussure and Deluc present a multitude of facts of this description. These geologists imagined, that they could only have been produced by enormous eruptions. De Buch and Escher have recently employed themselves upon this subject. The memoir of the latter, inserted in the Nouvelle Alpina of Steinmüller, vol. i. presents the general results in a remarkable manner. The following is a comprehensive view of them: Such of these blocks as are scattered over the low parts of Switzerland and Lombardy, come from the Alps, and have descended along their valleys. They occur every where, and of all sizes, up to 50,000 cubic feet, over the great extent of country which separates the Alps from the Jura mountains; and they rise upon the sides of the latter facing the Alps, to a height of 4000 feet above the level of the sea. They are found at the surface, or in the superficial layers of debris, but not in the strata of sandstone, molasse, or conglomerate, which fill up almost every where the interval in question. They are sometimes isolated, sometimes in heaps. The height of their situation is not connected with their magnitude; the smaller ones alone appear sometimes a little worn, but the large ones are not so at all. Those which belong to the basin of each river are found, upon examination, to be of the same nature as the mountains of the tops or sides of the high valleys in which the tributary streams of this river take their rise. They are already seen in these upper valleys, and are particularly accumulated at the places which are situated above some of the contractions of these valleys. They have passed over the lower hills, when their height has not been more than 4000 feet; and then they are seen upon the other side of the ridges, in the cantons between the Alps and Jura, and even upon the latter itself. It is opposite the mouths of the valleys of the Alps that they are seen in the greatest quantity, and at the greatest heights; those of the intervening spaces have not been carried so high. Among the chains of the Jura mountains, which are more remote from the Alps, they are only found in places which are opposite the openings of the nearer chains. From these facts, the author draws the conclusion, that the transportation of these blocks has taken place at a period subsequent to the deposition of the sandstones and conglomerates, and has perhaps been occasioned by the last of the revolutions which the globe has experienced. He compares the transportation in question to that which still takes place from the agency of torrents; but the objections presented by the consideration of the great size of the blocks, and the deep valleys over which they must have passed, appear to us to militate greatly against this part of his hypothesis.--Note E.