"No. Those who explore the region which we have left will find hills and valleys as before--awful crevasses, perhaps, and steaming cauldrons of water and mud. No vegetation, of course, but snow has perhaps fallen on some parts of the raw scar, and those explorers may be able to travel through a region that was--a week ago--the bowels of the earth! "The foundation rocks of the earth are left raw and exposed, as they may be after some terrific land-slip. But nothing more. We sail here high above the earth----" "Looks like we were _below_ it now," muttered Mark. "But if we have been observed from the earth--and of course those great telescopes at the Lick Observatory have found us out ere this--we will appear above her," said the professor. "Many things about this strange happening we may only guess at. Of one thing we are sure--we have air to breathe, water to drink, there are wild animals to kill for food, vegetation exists; we are, in fact, upon a miniature world which is not much different from that we have left--as yet, at least." "All that sounds mighty fine," interrupted Phineas Roebach. "And I expect you believe it all, Professor Henderson. But there's just one thing that _I_ believe: We're down here, two hundred feet or more from the top of this ice wall, and the game, or the vegetation, or anything else, isn't going to help us much while we're here. What I want to know is: How are we going to get out of this crevasse?" CHAPTER XVIII IMPRISONED IN THE ICE The oil hunter's demand was like a bomb thrown in their midst. The boys had been so deeply interested in the professor's relation of facts, and in the scientific phase of their situation, that the more practical questions of their mere existence on this island in the air had not before held their attention for long. "We've got to find some way of climbing out, I reckon," Mark said, slowly. "Well, find it!" snapped Phineas Roebach. "Let's talk of something practical. We'll freeze to death down here very soon, if we don't starve first." "Very true," said the professor. "Mr. Roebach is eminently practical. We must give our attention to the immediate peril that menaces us." At this moment Andy came forward with two hatchets and an axe. "These are the things we want, I guess," he said, quietly. "We've got to chop steps in the wall, and climb up in that way." "And abandon all our instruments--and the telescope?" exclaimed Professor Henderson. "And the _Snowbird_?" added Mark. "We can hoist all the small things up to the top of this wall--if we can get up there ourselves," said the old hunter. "Right you are, Mr. Sudds," declared Phineas Roebach, with vigor. "But the flying machine?" queried Jack. "It seems too bad to let it go." "We won't let it go, Jack," declared Mark.