"So ages passed, and might have continued so to pass until the end of time, had not necessity pressed once more upon the lizard-people in their cavern world. As I have said, the interior fires of earth's heart had pressed up close against the walls of their cavern, bursting forth in one place in that fall of flame which lighted their world; and now the molten fires began to press with more and more force against the walls, forced up by convulsions far beneath, and it was only a question of time until they would burst through those walls and sweep over all the cavern world in a great cataclysm of annihilating fire, instantly wiping out all life in the cavern. They must leave it, they knew, before that happened, so they decided to venture back once more to earth's surface. So they again placed the great disk-platform in position, and as it again swept ceaselessly up and down a party of them rose on it and opened the mouth of the shaft, in the swamp far above. It was that party, exploring the swamp on their great brontosaurs, who had captured me, and brought me down here to examine me. They had observed that intelligent creatures, men, now were established on earth's surface, that one of their cities stood near the swamp itself, and so they planned to send up first a striking force which would annihilate that city, annihilate Brinton, to prevent any possible interference from it. Then that first attacking force would return down the shaft, leaving guards at its mouth, and all the lizard-people and their dinosaur hordes would gather and assemble to pour up the shaft on the great disk and sweep out upon earth to conquer and annihilate the world we know. Besides their dinosaurs they had their own heat-beam projectors, those white globes in which they could condense and concentrate heat-vibrations, holding those vibrations static and releasing them at will in a concentrated ray.
"So they poured up the shaft to attack Brinton, and now that that attack has been made, their first striking force will return down here, gathering together all their hordes for the last attack on earth itself. Within hours, I think, that attack will take place, their hordes will swarm up the shaft and out over earth. Up at the shaft's mouth they have placed a great switch which will be turned on when all of them have left this cavern and are safely above, and which will release concentrated rays down here that will blast the cavern's walls and allow the floods of fire that press against them to burst into the cavern. For they fear that if they do not do so the imprisoned fires will burst forth in some mighty cataclysm that will wreck all earth. To loose the fires upon the cavern while they are in it would be to annihilate themselves, of course, but if it is done through the switch above after all of them have gained earth's surface there will be no harm to themselves.
"So all their plan has been carried out, so far, and within hours now their hordes will be sweeping up the shaft and out over earth. And what then? What will the forces of man avail him? What troops could stand against the thundering, gigantic dinosaurs? What guns against the deadly heat-beams? What airplanes could ever battle with the hordes of circling, swooping pterodactyls and the rays of their lizard-riders? For man, and for the world of man, there looms swift annihilation only, when the hordes of the lizard-men and their giant beasts sweep terribly upon him."
Morton's voice ceased, and he sat motionless, staring across the dusky little room with strange eyes. From the great corridor outside came the rasping voices of passing lizard-men, and the thundering tramp now and then of one of the great dinosaurs, but in the room itself was silence, as the two men regarded each other. Finally, with an effort, Rowan spoke.
"And so they plan to sweep out over all earth," he repeated, "plan to annihilate the world we know. And no chance of escape, for us, no chance to get back up to earth's surface——"
Morton raised his head, a sudden eagerness on his face. "There is still a chance," he said. "If we could get out of here—could get to that disk and back up the shaft! And we must, soon; for soon, I know, their hordes will be sweeping up that shaft, and when all are gone they will loose from above the fires upon this cavern, annihilating us unless we are slain by them before. Soon, I think, they will come to take you for questioning, also; since had they not intended to do so they would have slain you outright. And when they come—here is my plan——"
Swiftly he unfolded his scheme to Rowan, and wild as it seemed the other agreed to try it, as their only chance. Then they sat silent, for a time, in the darkness. It was a silence and a darkness torturing to Rowan. On earth above, he knew, the news of the terrible attack on Brinton would be flashing out, would be spreading terror and panic over all the world. And soon, now, would come the outward, resistless sweep of the lizard-men and their dinosaur hordes from this cavern world. Unless they escaped——
Hours fled by as they sat there, while from outside came the unceasing hurrying of lizard-men and dinosaurs through the giant corridor. Then from the distance came a loud bellowing and chorus of rasping cries, and a thunder of many gigantic feet passing the building where they lay imprisoned.
"The first attackers!" whispered Morton. "They've come back, from Brinton—they'll be assembling now beyond the city there, making ready for all to go——"