Mosses and LIcbens 



As the floating plants multiply along the borders of a body of 

 water, extending outward over the water as an anchored raft, 

 the immersed dead parts of the moss are continually dropping 

 disintegrated plant-tissue and so build soil from the bottom up- 

 ward. The accumulation of vegetable matter attached to the 

 living and floating plants on the under side causes the raft to 

 sink gradually ; so gradually that the new growth always rests 

 just at the surface of the water until the depth of the moss-raft is 

 sufficient to permit it to reach the bottom. In time, the weight 

 of the superimposed mass, together with chemical changes which 

 take place in the dead plant-tissue, convert the moss plants into 

 more or less compact peat. 



Ideal section of pond showing bog-moss growing outward from the shore. 



Ideal section of old pond showing bog-moss growing on the surface of the water 

 and forming a " quaking-bog." 



Thus a border of peat-moss soil is built around the shore; 

 and as new plants are continually growing on the water-line, 

 forming new rafts which in turn sink and make new moss-soil, 

 the body of water becomes gradually less until finally it dis- 

 appears altogether. During this process of marsh building a 

 "quaking bog" occurs, when the moss covers the whole surface 

 of the water but has not yet filled up the underlying water. 

 Both men and animals, while endeavouring to cross a "quaking 

 bog," have sunk through the overlying moss to be entombed in 

 the underlying peat; and, owing to the antiseptic quality of the 

 peat, the bodies have been kept in a state of preservation for 

 hundreds of vears, 



no 



