TEN INDIANA CAVES. 



103 



Where the water, thus oozing through the roof of 

 a cavern, is greater in quantity than can evaporate 

 before it falls, it drops from the stalactite to the floor 

 below. There it splashes outward and in time evap- 

 orates, leaving the solid particles brought down. 

 These accumulate one on top of another until finally 

 a cylindrical or cone-shaped mass protrudes upward, 

 slowly growing in size, each successive layer being 

 distinct from the preceding. This upward rising 

 mass is a stalagmite. It is almost always greater in 

 diameter than the stalactite above it. Often the two, 

 in time, meet and a column, or stalacto-stalagmite, of 

 crystalline limestone results. Down the sides of this 



Fig. 24 Showing the formation of caverns in limestone. 



, Sink-hole ; a, c, d,f, g, rooms in cavern ; 6, natural bridge, formed by the sinking 

 of the roof of a former very large room ; e, passages, showing numerous stalactites. 

 (After Shaler.) 



the incoming waters slowly flow instead of drop, 

 evaporating and leaving their solid particles as they 

 move, thus increasing in size the diameter of the col- 

 umn. If this action continues long enough, the whole 

 passage or room may be filled by these deposits and 

 all semblance of a cave obliterated. 



It will thus be seen that water, where it flows freely 

 and rapidly through massive beds of limestone, dis- 

 solves and erodes great cavities therein; where it 

 seeps and oozes through such beds it tends to fill up 



