《徐霞客游记·黔游日记七》
又向西在岭头上攀登，岭上多有中央下洼的坑穴，大些的盘绕成壑谷，垦为农田，小点的坠成洞穴成为陷阱。
又西向从岭头升陟，其上多中洼之宕，大者盘壑为田，小者坠穴为阱。
We climbed on the ridge heading west again, there were many concave pits on the ridge, the bigger ones gathered into valleys and ravines, which were reclaimed into farmland, the smaller ones formed into caves and became traps.