Under these circumstances, says Mr. Geikie, the “much wider extent of sea being exposed to the blaze of the tropical sun, the temperature of the ocean in equatorial regions would rise above what it is at present. This warm water, sweeping in broad currents, would enter the polar fiords and seas, and everywhere, beating the air, would cause warm, moist winds to blow athwart the land to a much greater extent than they do at present; and these winds thus distributing warmth and moisture, might render even the high latitude of North Greenland habitable by civilized man.” So we see that it is necessary to look for such geographical changes as will interfere with the movements of marine currents. Now, it is easy to see that comparatively small geographical changes would not only greatly interfere with these currents, but might even cause them to entirely change their course. An elevation of the northern part of North America, no greater in amount than is supposed to have taken place at the commencement of the Glacial Age, would bring the wide area of the banks of Newfoundland far above the water, causing the American coast to stretch out in an immense curve to a point more than six hundred miles east of Halifax, and this would divert much of the Gulf Stream straight across to the coast of Spain.23 Such an elevation certainly took place, and if continued westward, Behring’s Strait would also have been closed. It is to such northern elevations, shutting out the warm ocean currents, that a great many geologists look for a sufficient explanation of the glacial cold. Prof. Dana says: “Increase in the extent and height of high latitude lands may well stand as one cause of the Glacial Age.” Then he points out how the rising of the land of Northern Canada and adjacent territory, which almost certainly took place, “all a sequel to the majestic uplift of the Tertiary, would have made a glacial period for North America, whatever the position of the ecliptic, or whatever the eccentricity of the earth’s orbit, though more readily, of course, if other circumstances favored it.”24