THERE was a rocky hill not far away, and it was Joe who expressed a desire to go over and climb to the top.

“Fairly high,” he remarked. “Ought to be able to get a good view of the surrounding territory.”

“Yes,” Bob agreed. “Maybe we can catch sight of an Indian village in the distance. The unknown tribe! Be fine if we could be the ones to locate it, wouldn’t it?”

“Sure would. Professor Bigelow would be delighted beyond words. Think of the rumpus he’d kick up if we announced that we’d found the savages he’s been hunting.”

It was a distance of less than a half-mile to the foot of the knoll, and the youths made it in a very few minutes. Then they began the task of climbing the jagged side. There was little vegetation to hinder their progress, although twisted vines and shrubs were rather numerous on the ground.

“The undergrowth offers footholds that we could not otherwise find,” said Bob. “Here’s a place where it comes in handy, even though most of the time it’s merely something to avoid.”

At last, panting and perspiring, the youths reached the top of the hill and then turned to glance down below. Jungle, jungle, jungle! Nothing but heavily wooded country stretched before them. As far as the eye could see the great tropical forest loomed up—in green, brown, red. It was as though all the world were covered with dense vegetation. The boys turned about.

On the other side was the river, winding through gulches and hills and stretching out of sight in the distance. Opposite the hill were the boats, and under trees not far away were the explorers resting peacefully in the shade.

It was a spectacular view, and Bob and Joe spent several minutes in silently gazing down.

“No evidence of human habitation anywhere around,” remarked Bob, trying to single out a settlement somewhere in the distance.

In the vast, silent jungle sound travels far, and realizing this, the youths shouted to the others, to let them know of their commanding position.

“Now let’s get down from here and tramp on through the forest,” said Joe, finding a foothold in the heavy soil.

It was necessary to exercise more care in descending, for the rocks were pointed and dangerous to step on. A safe place had to be felt out cautiously.

The youths reached the bottom in a very short time, however, and followed a narrow trail that wound out of sight.

“Be impossible to cut through this jungle if there were no trails of any kind,” said Bob, his keen eyes unable to penetrate the tangled mass of vegetation on either side of them.

“Not without a machete, anyway,” nodded Joe. “Even then it would be a hard job.”

The youths hiked on until they came to a small stream that emptied into the river. They sat down on the bank to take in their surroundings.

On the other side of the stream was a break in the ground that indicated the presence of a gully—how steep, they did not know. They resolved to find out as soon as they had rested.

“Unless,” said Joe, “we can’t get across the creek. Never can tell how many alligators and piranhas have migrated here from the river.”

He picked up a stone and threw it with all his strength into the muddy water, hoping to arouse any life that might be lurking sluggishly out of sight. Once he thought he detected a slight ripple other than that caused by the stone but was not sure.

“Don’t believe I care to wade it,” backed out Bob. “Wouldn’t feel funny to have a toe nipped off by a piranha, or worse yet, to be carried into an alligator’s lair. Suppose we throw a log across for safety.”

They spent several more minutes sitting on the bank in idleness. At last Joe got up and looked about the near-by jungle.

“No logs around here,” he called to Bob, who had wandered along the bank.

Further search was not in vain. A small tree that had been uprooted by a hurricane lay in a patch of bushes not far away, and it was carried to the stream and thrown across. Then the youths began carefully walking along its narrow surface.

Bob reached the other side first, and he warned his friend to be careful. Joe was, and in a few moments also had crossed the log.

“Now let’s see what’s beyond that ravine,” he said.

They walked over to the edge and then halted abruptly, awe-stricken and spellbound at the wonderful panorama that stretched out before them. They were standing at the brink of a two-hundred-foot canyon, which sloped down and back up to form a perfect U. At the very bottom was a large grove of huge red flowers, which added not a little to the beauty of the scene.

“Some view,” breathed Joe, gazing far ahead at the distant jungle.

Bob nodded. “Bet we can see twenty miles or more,” he said. “And nothing but dense jungle.”

The youths spent several more minutes in looking off into space. They could not tear themselves away from the wonderful view. It seemed almost impossible to come suddenly upon such a gulch in a land that seemed fairly level.

At last Bob shouldered his rifle as a signal to move on.

“Can’t spend too much time here if we expect to do any more exploring,” he said, looking at his watch. “They’ll expect us back in another hour.”

“Where’ll we go next?”

“No difference to me. How about down the hill?”

They hiked down the gradual slope of the canyon, although the jungle was in places impenetrable.

When about halfway down, Joe stopped suddenly, his face an ashen gray, his limbs trembling. Bob’s eyes opened wide, and he clutched his rifle tightly.

The next moment there came a horrid hiss, and the thirty-foot anaconda lunged forward.