Although the incompetence of low temperature to cause glaciation, and the relative unimportance of the mountains in northeastern Canada and northwestern Europe throw most glacial hypotheses out of court, they are in harmony with the cyclonic hypothesis. The answer of that hypothesis to the problem of the localization of ice sheets seems to be found in certain maps of storminess and rainfall in relation to solar activity. In Fig. 2 a marked belt of increased storminess at times of many sunspots is seen in southern Canada. A comparison of this with a series of maps given in _Earth and Sun_ shows that the stormy belt tends to migrate northward in harmony with an increase in the activity of the sun's atmosphere. If the sun were sufficiently active the belt of maximum storminess would apparently pass through the Keewatin and Labradorean centers of glaciation instead of well to the south of them, as at present. It would presumably cross another center in Greenland, and then would traverse the fourth of the great centers of Pleistocene glaciation in Scandinavia. It would not succeed in traversing northern Asia, however, any more than it does now, because of the great high-pressure area which develops there in winter. When the ice sheets expanded from the main centers of glaciation, the belt of storms would be pushed southward and outward. Thus it might give rise to minor centers of glaciers such as the Patrician between Hudson Bay and Lake Superior, or the centers in Ireland, Cornwall, Wales, and the northern Ural Mountains. As the main ice sheets advanced, however, the minor centers would be overridden and the entire mass of ice would be merged into one vast expanse in the Atlantic portion of each of the two continents.