Answer:
Stalagmites, which are found in caves, are cone-shaped formations of calcium deposits made by calcium concentrated water dripping through the cave ceiling and onto the floor of the cave. Once the water evaporates, solid calcium is left behind thus forming a stalagmite. These deposits form like an icicle hanging from the cave roof.
However not to be confused with a stalactite (which is a cone-shaped calcium deposit hanging from the ceiling of a cave), stalagmites are cone-shaped icicle formations of calcium deposits that build upward from the cave floor.