The narrow tableland they were crossing was comfortingly flat, and he looked forward to descending a long grassy slope.

When they reached the edge, however, he got a rude disappointment, for the mist rolled up in waves with intervals between, and when a white cloud passed a gray light shone down into the gulf at his feet.
In the foreground there was a steep slope where rock ledges broke through the wet turf, and in one place a chasm cleft the hill.

He could not see the bottom, for it was filled with mist, but the height of the rock wall hinted at its depth.

A transverse ravine ran into the chasm, and he could hear the roar of a waterfall.

Then the mist rolled up in a white smother and blotted everything out.
"We cross the beck," said Helen.