RESIDUAL, GRAVITY-LAID, WATER-LAID DEPOSITS 29 



covered with a floating ma^s of vegetation which soon becomes suf- 

 ficiently solid to form a support for other plants such as rushes, 

 graces, and sedges. The growth of these soon so strengthen this 

 floating mass that still other species of swamp vegetation, including 



-&* 



Fia. 17. Typical eastern swamp land. The grass will be preserved from decay in 

 the water. Leaves from the forest will add to accumulation. A soil rich in organic matter 

 will result. 



Fia. 18. Florida everglades. 



some shrubs, gain a foothold. Forest trees may ultimately cover 

 it. While the process above described is taking place partly decayed 

 vegetation is dropping to the bottom of the lake from the under 

 side of the floating mass, and this accumulation may go on till he 



Fia. 19. Section showing one stop in the filling of tholnke with poat ; cc, moss growing 

 on surface of lake; dd, partly decayed peat that, has fallen from floating mass; ee, climbing 

 bog. (Shaler.) 



pond or lake becomes completely filled. Accumulations of peat also 

 occur around springs, giving rise to quaking bogs (Fig. 20). In 

 poorly drained areas the moss may grow on the surface of the soil 

 in sufficient amounts to fojrm peat. Oftener, however, it forms only 

 a soil rich in organic matter. 



