30 IN LOWER FLORIDA WILDS 



way to flow. It must then go downward through 

 the porous rock, eventually reaching the sea by 

 underground channels. Into these the tide often 

 flows back for long distances. 



Wherever along the coast there is a slight ele- 

 vation it is dignified (in a double sense) by being 

 called a "bluff"; every gentle swell of the surface 

 is at least some kind of ' ' heights ' ' ; some even apply 

 the name "mount" to their estates. Verily all 

 things are relative! 



The widespread mantle of sand which covers 



(most of the drier part of the State is composed of 

 grains of quartz. On the coasts it is mixed with 

 finely broken marine shells. The problem of 

 the origin of this siliceous sand is an interesting 

 one. Just how it came to be dispersed over the 

 whole region is also of interest. Doubtless it is of 

 northern origin and some of it was washed down 

 by the rivers of the Appalachian mountains. The 

 cold return current which sweeps southward along 

 the Atlantic coast constantly brings cargoes of 

 it; the sea throws it up on the land and the winds 

 disperse it. Some of it is a residue from limestone 

 rocks formerly covering parts of the State but now 

 destroyed by action of the air and water. The 



