《水经注·卷十一》
世祖命令耿况去攻打故安西山的贼兵吴耐氢，沿雹水而上十余营，全都击溃，指的就是这条水。易水又往东流经孔山北麓，山下有钟乳溶洞，洞中出产很美的石钟乳。采石钟乳的人打着灯笼去寻觅，入洞约一里，渡过一条潜流的地下河，不太深，人可涉水过去。洞中又奇妙地分出许多石洞，使得出入的人迷失方向，不知该往哪里走；因此在容易迷路的地方，人们一定会留下标记，回来时才能找到出洞的通道。洞顶又有大孔，朝天敞开，所以叫孔山。
易水又东径孔山北，山下有钟乳穴，穴出佳乳，采者篝火寻沙，入穴里许，渡一水，潜流通注，其深可涉，于中众穴奇分，令出入者疑迷不知所趣，每于疑路，必有历记，返者乃寻孔以自达矣。上又有大孔，豁达洞开，故以孔山为名也。
Emperor Shizu ordered Geng Kuang to attack Wu Naixian, a rebel soldier in Gu'an Mountain, and led more than ten camps up the Bao River, defeating them all. This refers to this river. The Yishui River flows east through the northern foot of Kongshan Mountain, and there is a limestone cave under the mountain, which produces beautiful stalactites. People who dig stalactites carried lanterns to search for them. They entered the cave for about one mile and crossed an underground river with a submerged flow. It was not very deep, and people could wade through it. The cave was also magically divided into many stone caves, making it easy for people to get lost and not know where to go; therefore, in places where it was easy to get lost, people would leave marks so that they could find the passage out of the cave when they returned. There was also a large hole in the top of the cave, open to the sky, so it was called Kongshan.