KINDS OF SOIL 47 



peat, which are made almost entirely by the decay 

 of plants, together with the little mineral material 

 that is blown in. The plant that accomplishes 

 the most in this direction is sphagnum moss. It 

 is a semi-aquatic plant and grows with great 

 luxuriance, making a thick carpet over the 

 water. Eventually the whole surface of a 

 shallow pond may be covered with sphagnum. 

 Other plants get a foothold upon this rushes, 

 sedges, cat- tails, cranberries, and the like. " Float- 

 ing ' cranberry bogs are quite common on the fresh- 

 water marshes of Cape Cod. Finally the covering 

 of plants is solid enough and has decayed suffi- 

 ciently for small water-loving shrubs, as huckle- 

 berries and alders, to get established. The float- 

 ing carpet gets thicker and heavier from the decay 

 of plants ; finally it either breaks and sinks at once 

 to the bottom of the stream or lake, or sinks into 

 it gradually and is covered with water. Then 

 begins the formation of peat. This process of 

 pond, swamp, and stream filling is going on in all 

 parts of the United States, mostly on a small scale 

 but sometimes on large areas. One million acres 

 of soil in the Kissimmee Valley of Florida have 

 been made in this way. The Great Dismal Swamp 

 of Virginia is another illustration. When drained 

 these swamps may be very fertile. 



TRANSPORTED SOILS 



Transported soils are more numerous. Among 

 the most important of these are the alluvial or 

 water-made soils. These are rarely stony, are 

 usually level, fine-grained and often very deep. 

 Water usually leaves the soil it carries in more or 

 less distinct layers; this "stratification" can often 



