it on the Serra. In Forfarshire, Lyell had noticed the peculiar contorted appearance of the beds of clay, gravel and sand of glacial formation, and also in the mud cliffs of Norfolk. He was anxious to know whether any of the ancient glacial heaps or moraines of the country south of the Alps, showed similar indications of pressure and forcing along by ice. “It happened that a railway was making from Turin to Ivrea, and although they cut through the lowest part of the terminal moraines near Mazzi they have thought it worth while to make a tunnel, through which we walked.” Near the entrance, “I was delighted,” wrote Lyell, “to see that curious folding of the strata, which will cause the same beds to be here pierced by a perpendicular shaft, yet without the beds having participated in the movement.” Full of this important subject he wrote fully on it. “In order to appreciate the distinctive character of this colossal moraine, you must reflect on the uniformity and evenness of the vast plain of the Po all round it, for, although really inclined from the Alps, it looks as level as the sea; then fancy the great mounds sloping up at angles of 20° and 30° to heights of 500, 1000, 1500 and 2000 feet; then consider that at the very extremity, as near Caluso, there are blocks of protogine which have come one hundred miles from Mont Blanc; also that the whole assemblage of stones is not like that which has issued from the Susa, or from any other valley, but confined to rocks such as now strictly belong to the basin of the Dora Baltea; also that the pebbles and fragments of stone, if of serpentine or any easily striable rock, are all striated, at least nineteen-twentieths of the whole, whereas in a recent glacier which has only travelled ten miles, you might only find one in twenty of the same stone striated; and lastly, think of the narrow vomitory which has disgorged this enormous quantity of material, the ravine above Ivrea being as obviously the source of the whole, as is the crater of Vesuvius the point from which its lavas have issued. When Gastaldi read his paper to the Geological Society at Paris, written jointly by him and Martens, Elie de Beaumont, who had many years before visited the ground, objected entirely to their conclusion that it was a moraine, but I never saw a stronger or more satisfactory case. But in the same paper the authors hazarded an opinion that although the old Alpine moraines stopped short after going a few leagues from the Alps, yet at some former time erratics had been conveyed to the summit of the Collina, just as “Pierre à Bot” and other blocks had been carried by the old Rhone glacier to the flanks of the Jura. Now when I read this at Zurich, I immediately recollected that in the valley of the Bormida, when I passed from Savona to Alessandria in 1828, I had been astonished at some very huge erratics of serpentine in the Miocene. Having never seen blocks of such enormous dimensions in any tertiary formation, I was