POSTGLACIAL, &>c, DEPOSITS OF CONTINENT 487 



supplanted the pine, and formed the principal tree in the Danish 

 forests. Lastly, the great oaks, too, disappear from the margin 

 of the Skovnwser, or peat-bogs, and a thick growth of sphagnum- 

 peat gathers over their prostrate trunks, forming the uppermost 

 peat-layer, upon the surface of which grew here and there the 

 warty birch (Betula verrucosa) and the alder (Alnus glutinosa). 

 The pine, I need hardly say, is no longer a native of Denmark, 

 nor is there any historical or legendary evidence of its ever 

 having been so. The oak which replaced the pine is now much 

 less abundant, and seems on the decline itself, the ground 

 being occupied by the beech as the principal tree, no trace of 

 which has yet been met with in any of the Danish bogs. 



Neolithic implements have frequently been found associated 

 with the buried pines of the forest-bogs, but they occur also in 

 connection with the oaks. It was during the ascendency of 

 this tree in the forests that the knowledge of bronze seems to 

 have been introduced to Denmark. How long a period elapsed 

 before iron came into general use we cannot tell. All we know 

 is that the Bronze Age endured for a very considerable time. 

 But whether or not it is the case, as some archaeologists have 

 supposed, that the beginning of the Iron Age may have been 

 synchronous with the introduction of the beech into Denmark, 

 there is no evidence to show. Unquestionably, however, that 

 Age belongs essentially to the epoch of the latter tree. It is a 

 mistake, however, to classify the Neolithic, Bronze, and Iron 

 Ages of Denmark as corresponding, more or less precisely, to the 

 epochs of pine, oak, and beech respectively. Stone implements 

 appear to have been in exclusive use well on into the oak epoch, 

 and for aught we know to the contrary the beautiful beech- 

 forests of Denmark may date back to the Age of Bronze. 



The peat-bogs of Norway abound in buried timber ; and in 

 many cases the trees occur on two horizons. The lower forest- 

 layer consists principally of oak, hazel, ash, and other deciduous 

 trees, with stools and roots in place, and now and then it is 

 underlaid by several feet of peat. Above this lower buried 

 forest comes a variable thickness of peat, from two or three up 



