Fourthly. But the gravest objection to the hypothesis of glacial erosion on so stupendous a scale is afforded by the entire absence of lakes of the first magnitude in several areas where they ought to exist if the enormous glaciers which once occupied those spaces had possessed the deep excavating power ascribed to them. Thus in the area laid down on the map, Figure 43, or that covered by the ancient moraine of the Dora Baltea, we see the monuments of a colossal glacier derived from Mont Blanc and Monte Rosa, which descended from points nearly 100 miles distant, and then emerging from the narrow gorge above Ivrea deployed upon the plains of the Po, advancing over a floor of marine Pliocene strata of no greater solidity than the Miocene sandstone and conglomerate in which the lake-basins of Geneva, Zurich, and some others are situated. Why did this glacier fail to scoop out a deep and wide basin rivalling in size the lakes of Maggiore or Como, instead of merely giving rise to a few ponds above Ivrea, which may have been due to ice action? There is one lake, it is true--that of Candia, near the southern extremity of the moraine--which is larger; but even this, as will be seen by the map, is quite of subordinate importance, and whether it is situated in a rock basin or is simply caused by a dam of moraine matter has not yet been fully made out. There ought also to have been another great lake, according to the theory under consideration, in the space now occupied by the moraine of the Dora Riparia, between Susa and Turin (see map, Figure 43). Signor Gastaldi has shown that all the ponds in that area consist exclusively of what M. de Mortillet has denominated morainic lakes, i.e. caused by barriers of glacier-mud and stones. Fifthly. In proof of the great lakes having had no existence before the glacial period, Professor Ramsay observes that we do not find in the Alps any freshwater strata of an age intermediate between "the close of the Miocenic and the commencement of the glacial epoch."* (* "Quarterly Journal of the Geological Society" volume 18 1862.) But although such formations are scarce, they are by no means wholly wanting; and if it can be shown that any one of the principal lakes, that of Zurich for example, existed prior to the glacial era it will follow that in the Alps the erosive power of ice was not required to produce lake-basins on a large scale. The deposits alluded to on the borders of the Lake of Zurich are those of Utznach and Durnten, situated each about 350 feet above the present level of the lake and containing valuable beds of lignite.