20 _ NEW YORK STATE MUSEUM 



In general, a swamp OT marsh is formed when the drainage in 

 any locality is so arrested that sufiQcient water is retained to 

 prevent complete decay of the vegetable matter that may be de- 

 posited. The greater amount of vegetable matter that accumu- 

 lates in a swamp is not due to the increased luxuriance of the 

 vegetation; in fact, the amount of vegetable matter that may be 

 deposited on the uplands may be greater than that which accumu- 

 lates in a swamp. On the upland, where the drainage is unim- 

 peded, any accumulation of vegetable matter is exposed to frequent 

 alternations of moisture and drouth, which hasten the process of 

 decay; but in a swamp, where the moisture is always about the 

 same, the decomposition is very slow, and is rather a process "of 

 deoxidation than oxidation, or decay. The various processes of 

 decomposition are well shown in a fence post when set in 

 moderately moist soil. The portion above ground is to all intents 

 and purposes in a dry atmosphere, and the rate of decay is very 

 slow. For a few inches above and below the surface of the 

 ground the decay is very rapid, because the soil retains the 

 moisture after rains; but in time of drouth this part becomes 

 dry. This alternation of moisture and drouth furnishes an ideal 

 condition for decay, and, when a post breaks, it is invariably at 

 this point. Below this zone of decay the moisture is more con- 

 stant, and the decay is less, and in many cases, when an old post 

 is dug up, it is found to be sound at both ends and almost rotted 

 off at the surface of the ground. This will serve as an explanation 

 of the fact that all that may be left of a great deposit of vegetable 

 matter where drainage is unimpeded is a thin deposit of mold, 

 while the same amount of vegetable matter in a swamp forms a 

 thick bed of peat, which in some cases may be fifty or even a hun- 

 dred feet thick. 



Inundated lands 



The most complete classification of inundated lands that has 

 come to the notice of the author is the one by Shaler [10th An. 

 Rep't U. S. Geol. Sur. p. 264] which is given below. 



