With the help of the grape vine and the aid of foot holds on the trees growing up from the sides of the pit, Walter succeeded in scrambling out. His face was pale and there was a look of horror in his eyes.
"I believe I would have died if I had been compelled to stay down there all night," he declared in a voice that trembled.
"What is there down there?" asked Charley regarding his chum curiously.
"The demon work of the fiends who built this wall," said Walter fiercely, "It's their old stone quarry. They didn't bring rock from the coast, they just dug down till they found the kind they wanted. And Charley, all around the sides, chained to the solid rock, are the skeletons of the workers."
"I am right about the Spaniards building this place then," Charley observed. "That's the way that most Christian nation always used to treat its captives."
"Let's go," his chum urged, "I guess my nerve is shaken from being down there with those skeletons so long. The sun is getting low, anyway. We will not have time to more than get back home before dark."
"You're right, we must go, but I wish we had time to go through the balance of those buildings," said Charley, regretfully.
The two boys soon regained the canoe and paddled safely past the floating crocodiles.
"We haven't solved the mystery, after all," remarked Walter, as he urged the canoe forward.
"No, but we have done far better," declared Charley, enthusiastically, "we have found a place where we will have ample protection in case we are attacked by the outlaws. I am in favor of moving our camp there to-morrow morning."