《徐霞客游记·滇游日记三十八》
于是靠着西边的山崖往南行一里多，有一圆形清澄的水池在西边山崖下荒芜的海子中，池子大处直径有一丈多，而且圆得如像镜子，澄澈晶莹水非常深，也称之为龙潭。
于是倚西崖南行一里余，有澄池一圆，在西崖下芜海中，其大径丈余，而圆如镜，澄莹甚深，亦谓之龙潭。
So I leaned against the cliff on the west side and walked more than a mile to the south. There was a round, clear pool under the cliff on the west side in the desolate sea. The pool was more than one meter in diameter. It was as round as a mirror, crystal clear and the water was very deep. It's also called Longtan.