Stalagmite site (4)
I believe the answer is:
cave
'stalagmite site' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cave that I've seen before include "Subject of speleology" , "Large grotto" , "Hollow in a cliff or underground" , "Primitive dwelling" , "Natural subterranean opening" .)