Dalongtan, located 1 km northeast of Jingxi County, Guangxi, Xuhuanhe Village, Yuweng Scattering Net, at the foot of the stone mountain on the east side, is the source of the Longtan River, and the pool is a rising spring. It is a large underground river exit. The water is inexplicable, the spring water is upwelling, and it becomes a lake. It is a lake, and there is a dragon Tibetan in the ancient water.