With the captain and Tyke in the lead, and Drew following behind to help Ruth over the hard places, they plunged into the unknown forest. After all, they went slowly, for Tyke had to favor what he called his "game leg."
For all the evidence that the wood afforded, it had been untrodden for many years. Giant ceiba trees reared themselves two hundred feet into the air. Lianas hung in festoons from the boughs like monstrous boa constrictors. Parrots flew squawking from branch to branch, and humming birds and butterflies of many hues and gorgeous beauty darted like bright arrows among the flowers.
The underbrush was thick and in some places impenetrable, and the treasure seekers would have found their progress very slow if it had not been for certain irregular trails that seemed to have been hewn through the woods at intervals. In some places these trails were many yards wide, while at others they narrowed to a foot or two. Nothing grew upon them, but they were covered by dead leaves and twigs of varying depths.
"Wonder how these trails came here," said the captain. "There are no footprints on them, and yet they must have been made by animals or men."
"Better keep our eyes peeled," warned Tyke.
The captain, who had scraped away some of the accumulated leaves and rubbish, gave a sudden exclamation.
"Why, this path is made of stone!" he cried. He dropped on his knees and examined more closely. When he rose to his feet his face was grave.
"It's lava!" he stated.
"Then the island must be volcanic!" exclaimed Drew, startled by the thought.
"Nothing very surprising about that when you come to think of it," Tyke declared. "We're right down here in the earthquake zone, where the earth's liable to throw a fit any time. Like enough this old whaleback is a sleeping volcano. She may blow up again some time."