"The question now is," said the professor suddenly, "where are we? On what sort of ground will these steps lead us out?"
"Give it up," said Walt. "I should judge, though, we must have come a mile or more through the tunnel."
"Quite that," agreed the professor.
"Well, the only way to find out our location is to climb up and see what we come out on," said Ralph, to put an end to the hesitation. "Who'll be first up?"
There was quite an argument over this, the professor declaring that, as he was the eldest, he ought to assume the danger. Ralph ended it by springing on to the first of the rough and slippery steps himself.
"Come on," he cried, though in a lowered tone.
A few seconds of climbing brought the boy to the mouth of the shaft. It was quite thickly over-grown with brush, and had evidently not been used for many years. For an instant Ralph hesitated before he shoved through the scrub surrounding the entrance, but when he did so, and stood outside the natural barrier with the professor and Walt Phelps beside him, he uttered an exclamation of unbounded astonishment, which was echoed by his companions.
Before them the moon was rising, tingeing the tops of the distant range with a silvery light. The illumination also flooded the scene before them.
They stood in a sort of vast, natural basin, of considerable extent, surrounded by rocky walls.