A gloom hung between the up-sweeping walls.

In a turn the passage narrowed to scarce a dozen feet, and here was darkness of night.

But light shone ahead; another abrupt turn brought day again, and then wide open space.
Above Venters loomed a wonderful arch of stone bridging the canyon rims, and through the enormous round portal gleamed and glistened a beautiful valley shining under sunset gold reflected by surrounding cliffs.

He gave a start of surprise.

The valley was a cove a mile long, half that wide, and its enclosing walls were smooth and stained, and curved inward, forming great caves.