《徐霞客游记·滇游日记三》
又往西南走一里，越过峡脊，其脊正中间平坦，但两边很陡。
又西南一里，穿峡脊而过，其脊中平而夹甚逼。
I walked another li to the southwest, crossed the ridge of the canyon, and the middle of the ridge was flat, but the sides were very steep.