stalagmite n 1: a cylinder of calcium carbonate projecting upward from the floor of a limestone cave
Stalagmite \Sta*lag"mite\ (st[.a]*l[a^]g"m[imac]t), n. [Gr. sta`lagma that which drops, a drop, fr. stala`zein to drop: cf. F. stalagmite.] (Geol.) A deposit more or less resembling an inverted stalactite, formed by calcareous water dropping on the floors of caverns; hence, a similar deposit of other material. [1913 Webster] Stalagmitic