Not knowing what had become of the hunter and the boys, the rescue party was puzzled. They looked on every side but saw no traces. The ground was so uneven that the professor suggested the hunter and boys might be lying wounded in a hollow, and screened from sight.
"We must scatter and look for them," he said.
Meanwhile the three in the ice cave had been looking about them. They saw what had brought them into the place. It was a big cavern hollowed out by nature in the frozen crystals, and leading to it was a smooth inclined plane of ice.
"How are we going to get out?" asked Jack, after all three had taken a survey of the cavern.
"Can't we walk up the place where we slid down?" asked Mark.
Jack was already busy trying to climb up the slippery place. It was much harder than it seemed. The incline was a glare of ice, and Jack's first attempt sent him sliding back with considerable force to the cavern floor.
"There's only one way to do it," said Andy. "You must take my hunting knife and cut steps in the slide. Then you will have some support for your feet."
The boys saw this was good advice and followed it. But the ice was frozen almost as hard as stone, and after chipping and cutting away for half an hour they only had three niches.
"At this rate we will have to stay here several days," said the old hunter, and there came an anxious note in his voice. "I wish we could send word to some of the others."
"Hark! What was that?" asked Jack suddenly.