Then she laughed softly again, once more accused herself of being "stupid," and began her explorations. Little by little as she grew accustomed to the scant light here she made out dim bits of detail. First she realised that her first conjecture had been quite right, and that this was the biggest cave by far that she had ever seen. She moved forward half a dozen steps, walking warily for fear of a fall and found that the light from the entrance died into deep darkness before it could search out the sides of the great cliff room. Then she went back out upon the ledge and gathered from the debris choked fissure an armful of broken bits of dry wood, twigs and needles from the cedar. In the pocket of her blouse were the matches which she always carried with her on her trips and in a moment a crackling flame near the cave door shot its wavering light deep into the dark interior. Then again she hurried in, eager to see what lay before her. Nowhere was the rock roof lower than ten feet save where far back it slanted toward the floor. The floor itself sloped so gently toward the back that it seemed quite level. She judged at first glimpse, as the firelight drew from the gloom a glinting granite surface here and there, that the chamber was twenty feet wide, that it reached back into the cliffs some fifty feet. She moved back toward what seemed the rear wall, found the floor pitching steeply ahead of her, noticed a rush of fresh air stirring her hair and paused suddenly, listening. A low sound that at first she could neither locate nor analyse, came faintly to her as from a great distance. With her hand on the rock wall she moved forward again slowly and cautiously. Still the floor pitched steeply as she went on, still the rush of air was in her face and with it the low rumble, growing more distinct. It was like nothing so much as rolling thunder, very far off, or the half heard beat of the ocean on a distant, rock bound coast. Again abruptly the way under foot grew almost level, she was on a plane some six feet lower than the ledge outside, and as she took another step forward, passing round a great slab of granite that jutted out in her way, she came upon an unexpected glint of light and a sight, seen dimly, that made her cry out in startled surprise.