This huge mass was being carried slowly down, by the glacier, and will be deposited at its foot some day or other. Once it formed a part of the valley side, and it fell on to the glacier, whose flanks had scrubbed it for many a long day. He particularly noticed how the glaciers had been advancing of late years (just as they are now receding). Lyell followed out these researches on the south of the Alps, and he first of all made many excursions, accompanied by Gastaldi, one of the best of the scientific men of Turin, and by Michelotti, in order to compare the shells which are found fossil in the middle tertiary strata on the south of the Alps, with those of the molasse of Switzerland to the north. He found that these strata, separated by the great mass of the mountains, resembled each other somewhat mineralogically as well as in their fossils, but he was not able to make out that they were exactly of the same geological age, although it was highly probable. He wrote on the glaciers ancient and modern of the southern slopes of the Alps, and in relation to the former—“A comparison also of the extinct glaciers of the Italian and Swiss sides of the Alps can better be made from Turin than from any other place. Before my arrival I had seen, on the banks of the Lago Maggiore, some good examples of erratics and of moraines which had come from the Simplon, but these, as you might suppose, _a priori_ are far inferior to those which have descended from the Val d’Aosta, or which belong to the mighty glacier derived from the combined snows of the Mont Blanc and the Mont Rosa group of Alpine heights. This glacier, although perhaps of less gigantic dimensions than that of the Rhone, has certainly left, as Gastaldi first pointed out in a memoir on the subject, a far more imposing monument of itself on the plains of the Po, than have the extinct glaciers of the Rhone or the Rhine, in the lower country of Switzerland.” He noticed that “J. D. Forbes has well shown in his book on the Alps, that a glacier is a peculiarly sensitive instrument for measuring the average of heat and cold, and that every slight difference of temperature causes it to increase or lessen in height and length.” And pursuing the argument, remarks that as geologists had shown from the nature of the fossil remains in lately formed gravels, that arctic animals lived far south in Europe, shortly before the existing state of things, we ought to find evidences of the cold climate which allowed those animals to live so far south. These evidences are at hand in the remains of the glaciers, which in those days extended far lower than they do now, and were grander in extent. Thus a lofty mound or ridge, two thousand feet high, called the Serra, running into the great alluvial flat of the River Po, where maize and mulberries grow, is a huge terminal moraine of an ancient glacier. Ice reigned supreme there in the glacial period, and brought down the stone from the distant hills, and deposited