The excited cries of the old miner brought Mr. Damon and Mr. Parker to the pilothouse on the run.
"Bless my refrigerator!" exclaimed Mr. Damon. "Are there more of those savage, shaggy creatures down there?"
"No, but we are over th' caves of ice," explained Abe. "That means we are near th' gold."
"You don't say so!" burst out the scientist. "The caves of ice! Now I can begin my real observations! I have a theory that the caves are on top of a strata of ice that is slowly moving down, and will eventually bury the whole of the North American continent. Let me once get down there, and I can prove what I say."
"I'd a good deal rather you wouldn't prove it, if it's going to be anything like it was on Earthquake Island, or out among the diamond makers." said Tom Swift. "But we will go down there, to see what they are like. Perhaps there is a trail from among the ice caves to the valley of gold."
"I don't think so," said Abe, shaking his head.
"I think th' gold valley lies over that high ridge," and he pointed to one. "That's where me an' my partner was," he went on. "I recognize th' place now."
"Well, we'll go down here, anyhow," decided Tom, and he pulled the lever to let some gas out of the bag, and tilted the deflection rudder to send the airship toward the odd caves.
And, curious enough did our friends find them when they had made a landing and got out to walk about them. It was very cold, for on every side was solid ice. They walked on ice, which was like a floor beneath their feet, level save where the ice caves reared themselves. As for the caverns, they, too, were hollowed out of the solid ice. It was exactly as though there had once been a level surface of some liquid. Then by some upheaval of nature, the surface was blown into bubbles, some large and some small. Then the whole thing had frozen solid, and the bubbles became hollow caves. In time part of the sides fell in and made an opening, so that nearly all the caves were capable of being entered.
This method of their formation was advanced as a theory by Mr. Parker, and no one cared to dispute him. The gold-seekers walked about, gazing on the ice caves with wonder showing on their faces.