Bogs, Their Nature and Origin. 



37 



ulmic (as well as apocrenic) acid, readily soluble in caustic and 

 carbonated alkalis, and forming insoluble salts with the earths 

 and metals; while another portion, ulmin, is insoluble in the 

 same, but gradually becomes soluble by oxidation. The gases 

 formed under these conditions are carbon dioxide and marsh 

 gas, the former predominating in the earlier stages, the latter 

 in the later stages. Owing' to the antiseptic action of bog water 

 and peat deposits, the remains of plants, of animals and of man, 

 have been recovered from bogs in a fair state of preservation. 

 Through this preservation a succession of layers can be detected 

 in the vegetal remains out of which the peat has been formed. 

 This is especially the case where the peat deposits are formed 

 by the conversion of a lake into a bog. Thus in Europe, 

 according to Geikie,* among the bottom layers, traces of rush 

 {] uncus), sedge, Iris and fescue-grass (Festuca) have been 

 observed, while in the bottom layers, where lakes have been 

 converted into bogs, shells of Limnaea, Planorbis and other 

 lacustrine mollusks occur. The next and chief layer of peat 

 consists mainly of matted fibers of different mosses, particularly 

 sphagnum, mingled with the roots of sedges, grasses and aquatic 

 plants. The upper layers frequently abound in heaths, which 

 appear, when the bog surface begins to show evidences of 

 senility. Trees may invade an old bog to add their quota to 

 the bog deposits. In some cases whole forests have been buried 

 by the invasion of bog mosses and their remains, as the writer 

 has observed in a study of the peat bogs of Ireland, have been 

 preserved in the form of bog oak which, when removed from 

 the peat, have been fashioned into crosses, walking sticks and 

 other ornamental objects. 



The study of bog deposits has afforded data as to the forest 

 succession in northern European countries. Upon the character 

 of the forest succession and the order of that succession depends 

 a rational forestry system. In Denmark, for example, it has 

 been discovered by a study of the peat bogs, that the Scotch 

 pinef {Finns sylvestris) and white birch (Betula alba) are char- 

 acteristic of the lower layers. That is, when these particular 

 layers of peat were deposited, the forests in the neighborhood 

 of the developing bog consisted of Scotch pine and white birch. 



* Geikie, Sir Archibald. Text Book of Geology, page 478. 



t The Scotch pine does not occur in the modern flora of Denmark. 



