And from there on, for a long time, we followed the bottom of a great gorge.

The rock walls were bold and often sheer, and the upper line of mountain horizon was graceful and varied.

The cliffs were mostly limestone, and presented remarkable examples of folding and dislocation.

The long roots of trees, following exposed rock surfaces downward for yards, and twisting and bending to find lodgment in the crevices, were curious.

Great tufts of a plant with long, narrow, light-green leaves hung down along vertical rock faces.