STALACTITES AND STALAGMITES. 



311 



until a small protuberance of solid lim'estone is formed, nearly the 

 shape of a drop of water. This protuberance becomes enlarged by 

 water trickling over it, and takes the shape of an icicle. The water 

 that drops upon the floors of caverns, sometimes deposits a thick coat 

 of limestone over the whole floor; but in those parts where the drops 

 fall most frequently, a more copious deposition of calcareous earth 

 takes place, in the form of tubercles : these are the stalagmites. In 

 some instances the stalactites and stalagmites increase, until they 

 nearly fill the whole cavern. 



