Answer: stalagmite

AnswerCrossword Clue
STALAGMITECavern-floor buildup
STALAGMITECave deposit
STALAGMITEUnderground phenomenon.
STALAGMITESpelunker's obstacle
STALAGMITEA certain point underground?
stalagmiteA mound or tapering column rising from the floor of a cave, formed of calcium salts deposited by dripping water and often uniting with a stalactite
stalagmitea roughly conical shaped speleothem that rises from the floor of a cave