I agreed, and we put the idea into effect at once, rising to a height of nearly two miles and then racing away to the west in a curving course that would eventually bring us back to our starting point. As we sped on, both Lantin and myself were at the observation windows, scanning the landscape in every direction, but only boundless fields of ice met our eyes. We reached a point some two hundred miles north of our starting position, and had begun to curve back toward that position, when Lantin uttered a sudden exclamation and hastily stopped the car's progress. "Look!" he cried, excitedly, pointing away to the north. At first I could see only the glaring ice, when I gazed in that direction, but gradually my eyes made out a distant spot of black against the horizon. Before I could comment on it, Lantin headed the car around and opened up on the power so that we shot north toward that distant spot with full speed. On we went, until the spot had changed to a thick line, and its color from black to green. And as we neared it, we saw that there the ice ended, and beyond it were green fields and hills and valleys, with patches of gnarled, stunted trees here and there. On we fled, still north, until the ice-fields had faded from view behind us, and the chilling cold we had felt above them had given way to a summer warmth. And the first dwarfed trees had changed to towering giants of the forest, though mostly the country below us was open fields and ranges of green-clad hills. "I can't understand it," I told Lantin. "Who ever heard of a warm, semi-tropical country like this existing farther north than fields of glacial ice?" "It is strange," he admitted, "but it's understandable, at that. You remember the explorer who found that warm, sunken valley in Alaska, somewhere? It was heated by steam, literally, for the interior fires of the earth had in some way bulged up near the surface of the ground, there, and their heat acting on the valley's springs and rivers made it a great steam-heated depression of almost tropical warmth. Probably the same thing has happened here, a shift of the earth's interior forcing up part of its inner molten core, the heat of which would counteract the glacier and keep it from covering this section of the country. Strange things happen under the earth's surface, Wheeler." "You may be right," I said, "but there's no life here, Lantin. No--" I broke off, suddenly, staring out of the car's western windows. The western sky was glowing, for it was near to sunset, and there, far away, standing out black against the brilliant sky, was a city.