A moment he lay thus, then crept with Morton to the disk's edge and stared down with him at the gray city which now lay far below. They saw, pouring into the plaza, a great mass of huge dinosaurs and a vast throng of the lizard-shapes, an eddying throng that was moving now toward the plaza and the fiery lake from all the city's wide and branching streets. The next moment all this was blotted from sight as the disk shot smoothly upward into the darkness of the great shaft, flashing up that shaft amid a thundering of confined winds. Over the raging of those winds Rowan shouted in the other's ear. "They've gathered down there!" he cried. "When the disk goes down again they'll come up with it, after us! We have only minutes----" Morton shouted back. "The switch! If we could open that wheel-switch up there, let loose those fires below----" Rowan gasped. The switch! That switch which the lizard-men had themselves prepared, to use after they had all come up from their cavern-world. If they could open it, could release upon that cavern-world the raging fires which pressed against its walls, it would mean annihilation for the lizard-people and all their giant reptile hordes. If they could---- Abruptly he grasped the other's arm, pointed mutely upward. Far above them a spark of pale white light was glimmering, a spark that changed to a spot and then to a little circle of pallid light as their disk-platform flashed up toward it with tremendous speed. And now, as that circle of white light widened, the disk was beginning to slow its speed a little, the downward-flashing metal walls beside them were moving past them more slowly. Up, up the great disk lifted, while the two men crouched tensely at its edge, and then it had floated up until it hung level with the mouth of the great shaft, beneath the radiance of the suspended bulb.