Something clicked behind me like the turnstile at the gate of a show.
Then we began to ascend steps, still in utter darkness, and a great booming fell on my ear.

It was the falling river which had scared me on my former visit, and I marvelled that I had not heard it sooner.
Presently we came out into a gleam of moonlight, and I saw that we were inside the gorge and far above the slab.

We followed a narrow shelf on its left side (or 'true right', as mountaineers would call it) until we could go no farther.

Then we did a terrible thing.

Across the gorge, which here was at its narrowest, stretched a slab of stone.