《徐霞客游记·粤西游日记三十》
又向北在岭脊上前行半里，远望西北的石山与所登的土山分为条状延向东，下边隔着断绝的壑谷，有一支土山山脊横向连接在其间，先前渡过的向北流的溪水，竟然透过山脊后流入山坞里的洞穴中，不从山涧中流了。
又北行岭脊半里，望西北石山与所登土山分条而东，下隔绝壑，有土脊一枝横属其间，前所渡北流之水，竟透脊而入其坞穴中，不从山涧行矣。
Travelled north along the ridge for another half a mile and looked out to the northwest. The stone mountain and the earthen mountain where I was, stretched out to the east as strips, separated by an impassable valley below. A ridge of the earthen mountain extended across them, connecting them. The stream that was flowing north that I had crossed earlier, somehow flowed into a cave in the mountain after passing through the ridge, disappearing from the mountain stream.