Columbia subject headings:
Caves.
Corwith Expedition, 1895.
Yucatán (Mexico : State)--Antiquities.
Yucatán (Mexico : State)--Description and travel.
Harvard subject headings:
Caves--Mexico--Yucatán (State)
Corwith Expedition, 1895.
Yucatán (Mexico : State)--Antiquities.
Yucatán (Mexico : State)--Description and travel.
Princeton subject headings:
Caves.
Corwith Expedition, 1895.
Yucatán (Mexico : State)--Antiquities.
Yucatán (Mexico : State)--Description and travel.