REPORT OF THE DIRECTOR AND STATE GEOLOGIST 1903 23 



When reclaimed by drainage, they make excellent garden land, 

 though the cost of drainage is greater than in the case of most 

 fresh-water swamps. 



Mangrove marshes. South of Fernandina and thence through- 

 out Florida, mangrove marshes take the place of grass marshes. 

 The roots of the mangrove develop in salt water, and the plant 

 spreads by means of rootlike processes which implant themselves 

 in the marine mud, while the tree itself is entirely above water. 



Fresh-water swamps. Though marine marshes and fresh-water 

 swamps are sharply defined in the character of the vegetation 

 and in the periodicity of inundation, the two have their point of 

 meeting in the estuarine or delta swamps. It is hard to draw the 

 line of distinction between the different classes of fresh-water 

 swamps and a study of conditions will force on the student the 

 conclusion that all fresh- water swamps are modifications of lake 

 swamps. The causes of lake formation in general will not be dis- 

 cussed for the reason that this article has only to do with lake 

 filling. A logical treatment of the subject might start with a 

 discussion of any one of the four classes of fresh-water swamps, 

 but for convenience the author will discuss them in the order 

 given below: 



1 Lake swamps 



la Lake margins 

 lb Quaking bogs 



2 Kiver swamps 



2a Terrace 



2b Estuarine or delta 



3 Upland swamps 



3a Climbing bogs 

 3b Wet woods 



4 Ablation swamps 



Lake swamps. Near the shores of almost any lake or pond a 

 growth of rushes and other aquatic plants may be seen, and 

 usually they are found more abundant in sheltered bays where the 



