Answer: stalagmites

AnswerCrossword Clue
STALAGMITESFeatures of some caves
STALAGMITESUppers?
stalagmitesA 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
stalagmitesSTALAGMITE, a roughly conical shaped speleothem that rises from the floor of a cave