穿洞形成于溶蚀发育的洞穴，是已脱离地下水位、高悬于山体上部且两端为开口状的残留通道。洞壁常有边槽、流痕、贝窝等形态，洞体成通道式，是流水岩溶的一种标志性形态。广西平果平治河岩溶自治区级地质公园内穿洞众多，其中月亮山穿洞和光岩穿洞颇具代表性。 3. Light-through Cavity The light-through cavity is formed in the cave where the dissolution is developed. It is a residual channel that is out of the underground water table and at the top of the mountain, with open ends. Side grooves, solutional ripples and scallops were developed on the wall of the light-through cavities. It is a symbolic form of flowing water karst. There are many light-through cavities in the Pingzhi River Karst Autonomous Region Geopark in Pingguo Pingzhi River Karst Autonomous Region-level Geopark, Guangxi. Among them, the Moon mountain light-through cavity and the Guangyan light-through cavity are quite representational.