《水经注·卷三十一》
北面好像要崩塌似的，勉强才可侧足，喜欢冒险的人常有去攀登的。
北面有如颓落，劣得通步，好事者时有扳涉耳。
The north side looks like it is about to collapse, so it can only be climbed sideways with great difficulty. People who like adventures usually climb it.