《徐霞客游记·滇游日记三十四》
中午后，再向东沿南山行。半里，它北边又隆起一座长形土阜，如一半月亮横在前方，这是长洞山。
既午，复东向循南山行，半里，其北复起一长阜，如半月横于前，是为长洞山。
After noon, go east along the Southern Mountain. Half a mile, to the north, there is an elongated mound, like half a moon lying in front, this is the Longdong Mountain.