“You will see even more wonderful sights,” Dr. Rander told him. “And before we go many miles farther.”

Indeed the boys found much to hold their interest. The awe-inspiring cliffs, the stupendous rocky crags, the foamy river below, the breath-taking heights—all these held a certain fascination for the two youths. They found themselves absently bending their efforts too much on seeing the sights and not enough on making out the dangerous trail.

“Be careful here,” Dr. Rander warned, as Joe almost slipped and fell. “It surely would not do to roll down this steep slope.”

“That would about put an end to everything for me,” said Joe with a grim smile.

The trail curved on up the mountainside until it reached a high pointed crag, which had been visible for several miles. Then it gradually circled around until it reached the base of the mountain.

“What’s that noise?” demanded Bob Holton, stopping quickly to listen to a deep rumbling sound that increased with every moment.

Dr. Rander looked up. Then his eyes opened wide with terror.

“It’s an avalanche!” he cried hoarsely. “Tons of rocks are coming down at us!”