“You sure were lucky,” remarked Joe. “Perhaps it wouldn’t have been discovered at all if you hadn’t located it.”
At a point near the ledge, the mountain grew so steep as to make climbing a very arduous task. A single misstep would have meant a horrible plunge into the roaring rapids below.
At last they came to the top of the ledge, before the notch cut in the mountainside.
“See that dark entrance?” asked Dr. Rander. “That is a tunnel that leads to the cavern. Come.”
The youths followed the old man into the opening, which was made light by the latter’s flashlight. The passage seemed to lead steadily upward, probably into the peak of the mountain.
“Do you suppose this tunnel was constructed?” asked Joe, after five minutes had passed.
“I believe so,” Dr. Rander returned. “When we get farther on, you will think so too.”
Fifteen minutes of walking brought them to the end of the tunnel. From all appearances there was nothing but natural rock before them.
“Watch,” said Dr. Rander, moving over to the end of the cave.