壶穴（砺剑池）Pothole (Sword Grinding Pond)  구혈(여검지) 基岩河床发育北东向裂隙，水流携带砂石沿裂隙侵蚀下切和侧蚀，经过长期的研磨、摩擦、刻划、撞击等过程，形成长13米，均宽1.5米，最深1.2米的近方形的凹坑，即壶穴。其状如刀剑切割，被当地人称为“砺剑池”。 The bedrock riverbed is developed with northeast-oriented fractures, where the water flow carries sand and gravel that erode downward and laterally along the fractures. After long-term processes of grinding, friction, scratching, and impact, a near-square depression with a length of 13 meters, an average width of 1.5 meters, and a maximum depth of 1.2 meters is formed, known as a pothole. Its shape resembles that of a sword cutting, and it is referred to “Sword Grinding Pond” by locals. 기암하상은 북동쪽으로 갈라진 틈을 발육하여 물줄기가 모래와 자갈을 가지고 갈라진 틈을 따라 침식하여 절단하고 측면 침식하며 장기적인 연마, 마찰, 조각, 충돌 등 과정을 거쳐 약 13미터, 너비 1.5미터, 최대 깊이 1.2미터의 사각형의 움푹 패인 구덩이, 즉 구혈을 형성한다. 그 모양은 도검 절단과 같아서 현지인들에게 ‘검을 연마하는 연못(여검지)’라고 불린다.