“How do you mean?”
“Why, I’m certain that I saw the rock move.”
“Great Blue Bells of Scotland, you’re dreamin’, boy. That rock is as solid as the etarnal hills.”
“I’m not so sure. I’m sure I saw it quiver a minute back, when that roll of thunder shook the ground.”
“Guess you’re mistaken, boy. Jumpin’ Jehosophat! Come back here! Quick!”
Ralph had stepped forward to gaze up at the big poised rock. As he did so, there had come a brilliant flash and an earth-shaking peal of thunder.
The ground quivered and shook, and as it did so the great stone gave a lurch forward. The next instant it crashed downward right upon the spot where Ralph had been standing. But the boy had been snatched back by Jim’s muscular arm.
“Safe! Thank the Lord!” gasped out Mountain Jim fervently.
“But look at the rock, Jim! It has blocked the entrance to this place! We’re prisoners!”
It was only too true. The big stone was lodged in front of the small cave mouth, shutting out the light and almost excluding the air except for a small space at the top. To all intents and purposes they were as much captives as if a jailer had clanged a steel gate upon them and locked it securely.