CHAPTER FIFTEEN.
A LIVING TOMB.
Literally buried alive, as Walt Wilder had said, were he and his companion.
They now understood what had caused the strange noise that mystified them--the rumbling followed by a crash.

No accidental _debacle_ or falling of a portion of the cliff, as they had been half supposing; but a deed of atrocious design--a huge rock rolled by the united strength of the savages, until it rested over the orifice of the shaft, completely coping and closing it.
It may have been done without any certain knowledge of their being inside--only to make things sure.

It mattered not to the two men thus cruelly enclosed, for they knew that in any case there was no hope of their being rescued from what they believed to be a living tomb.
That it was such neither could doubt.

The guide, gifted with herculean strength, had tried to move the stone on discovering how it lay.

With his feet firmly planted in the projections below, and his shoulder to the rock above, he had given a heave that would have lifted a loaded waggon from its wheels.
The stone did not budge with all this exertion.