“What has gotten into the lad?” Case asked, one night when the Rambler lay at anchor in a bay just above the Rio Negro river. “He seems to be watching for some sign or signal, but refuses to tell what it is.”
No one ventured a reply, and Jule pointed away to the valley of the Rio Negro.
“That river,” he said, to change the subject, “is a thousand miles long. Its head waters rise in Columbia and Guiana. Perhaps some of the water that trickles down to the Amazon comes from the oldest land on the continent.”
“I guess not!” Alex interrupted. “The oldest land is somewhere near the center of Peru.”
“The oldest land is in Guiana,” insisted Jule. “Many millions of years ago an island rose out of the water there. That was the first of the continent of South America. The Andes were forced up later by the wrinkling of the crust of the earth as it dried out. But the Andes lifted and lowered a great many times before they got their noses into the air for keeps. Why, there is a salt spring 14,000 feet above sea level down here. That deposit of salt was made when the ocean washed the spot where it lies!”
“There’s gold down here, too,” Alex declared. “I’ve read that the gold mines of Peru were sealed up when the Spanish came, and that they have never been discovered to this day.”
“What do you know about that, Frank?” asked Case, as the boy came up.
Frank made no reply, but walked back to his old place on the rear platform, which he reached by creeping over the low roof of the cabin.
“Perhaps there is gold on this Cloud island,” suggested Jule.
“There is something there worth fighting for,” Case argued. “Then, where did the kid get all that gold? He brought it out with him, you know, and hid it in a tree!”