“But when are we going to find one?”
“You know as much about that as I do. Remember none of us ever has been over this trail. For aught I know we may have to sleep standing up to-night.”
68“Well, I reckon I’d just as soon fall off before dark as after. Anyhow, I don’t propose to sleep on this trail as it looks to me now–”
“Hark!”
Tad’s voice was sharp and incisive. He was holding up one hand to impose silence on his companions. Walter Perkins’ face grew pale, the fat boy’s eyes were large and frightened. Professor Zepplin halted his pony sharply and turning in his saddle glanced anxiously back toward his charges.
“What is it?” stammered Rector.
“I don’t know,” answered Tad Butler. “It’s something awful, whatever it is.”
“Have no fear, young men. I know what that sound is. There is no danger here where we are, for–”
The Professor did not complete his sentence. The distant rumbling that had at first attracted their attention suddenly merged into a deafening roar, and the trail quivered under their feet. The ponies snorted and threw up their heads, chafing at the bits.
“Hold fast to your horses!” shouted Tad. His voice was lost in the great roar that now overwhelmed them, sending terror to the hearts of every Pony Rider Boy on that narrow ledge of rock known as the Yakutat trail.