"And they figure," said Barnes abruptly, "that locking onto a ship with the landing-grid might be like an earthquake." He stopped. "An earthquake, now--" "Not much vulcanism on this planet," Hardwick told him. "But of course there are tectonic quakes occasionally. They made this island." Barnes said uneasily: "I don't think, sir, that I'd sleep well if I lived here." "You are living here for the moment. But at your age I think you'll sleep." The bolster-truck turned, following the highway. The road was very even, and the motion of the truck along it was infinitely smooth. Its lack of vibration explained why it was permitted to move when all other vehicles were stopped. But Hardwick reflected uneasily that this did not account for the orders of the Sector Chief forbidding the rocket-landing of a ship's boat. It was true enough that the living-surface of the island rested upon slanting stone, and that if the bottom were wet enough it could slide off into the sea. It already had moved. At least one place was moving at four inches per hour. But that was viscous flow. It would be enhanced by vibration, and assuredly the hammering of seas upon the windward cliff should be lessened by any possible means. But it did not mean that the sound of a rocket-landing would be disastrous, nor that the straining of a landing-grid as it stopped a space-ship in orbit and drew it to ground should produce a landslide. There was something else--though the situation for the island's civilian population was assuredly serious enough. If any really massive movement of the ground did begin, viscous or any other; if any considerable part of the island's surface did begin to move--all of it would go. And the population would go with it. If there were survivors, they could be numbered in dozens. The tall tamped-earth wall of the Headquarters reserve area loomed ahead. Sector Headquarters had been established here when there were no other inhabitants. Seeds had been broadcast and trees planted while the survey buildings were under construction. Headquarters, in fact, had been built upon an uninhabited planet. But colonists followed in the wake of Survey personnel. Wives and children, and then storekeepers and agriculturists, and presently civilian technicians and ultimately even politicians arrived as the non-Service population grew. Now Sector Headquarters was resented because it occupied one fourth of the island. It kept too much of the planet's useful surface out of civilian use. And the island was now desperately overcrowded. But it seemed also to be doomed.