"Not a bad idea," said the Doctor. "The only hitch would be getting him out of here."
As Dave backed away for a better view, his foot struck something hard. Flashing his light upon it, he found it to be the skull and tusks of a walrus. They were as black as coal.
"I've made a find!" he exclaimed. "These tusks we may take with us, and old ivory is about as valuable as precious stones."
The discovery seemed to waken the Doctor to their peril.
"That walrus," he said, "wandered in here and was drowned by the rising tide. He can breathe under water, but cannot stay down over ten minutes. We can't breathe at all under water. The tide is setting in."
These words sent the crew scurrying back to the submarine. Already the tide had risen sufficiently to float the craft. All hands hastened to re-embark.
"If we set our course directly at right-angles to this beach and keep it there," said Dave, "it should bring us to safety."
This was done, and, after many a turn and twist, they caught a gleam of light. Submerging, they were soon beneath the ice-floe once more. With a sigh of relief, Dave gave the order to rise at the first water-hole. There they might take their bearings.
A half-hour later the party was gathered on the deck gazing away at an island above which there towered a snow-capped mountain. Down the side of the mountain might be distinguished the winding, blue course of a great glacier.
"Our glacier!" said Dave. "Some glacier, I'll say!"