QUATERNARY DEPOSITS OF BRITISH ISLES BROOKS. 



547 



per communis. The rise of temperature still continued, reaching a 

 maximum more than 2° above the present, when the upper limit of 

 the fir in south Norway was 350 to 400 meters higher than now, and 

 at Folgefonn, in 60° N., as much as 550 meters, and all the coastal 

 islands, now barren, were clothed with forests as far as Ingo Island 

 at North Cape. From this point the climate deteriorated. 



In the peat bogs of Norway, 0yen also found evidence for a suc- 

 cession of wet and dry periods. The Tapes period (the equivalent 

 of the Litorina period) had a warm, humid climate with a small an- 

 nual range; this was the beginning of the neolithic period in Nor- 

 way. The peat of this period is overlain by a layer of tree stools 

 representing a drier climate, which at first was warmer than the 

 present, forming the neoboreal period, but afterwards became cooler, 

 forming the subboreal period. This in turn was followed by a re- 

 newed formation of peat due to a period of greater rainfall, the sub- 

 Atlantic period, the subboreal and sub-Atlantic corresponding to the 

 Ostrea stage. The present period is characterized by a somewhat 

 drier climate, for trees are now growing upon the peat in many 

 places. 



In the deposits of the Mactra stage, preceding the Tapes period, 

 0yen found plants requiring a drier and warmer climate than that 

 of to-day, but the marine Mollusca indicate a relatively low tem- 

 perature of the sea, so that there was probably a continental type of 

 climate with warm, dry summers and severe winters. This is borne 

 out by the fact that terraces of erosion were far more marked than 

 terraces of deposition during this period. Conditions in Denmark 

 were fairly similar to those in Scandinavia, except that trees occur 

 more frequently in the peat bogs, and there is no distinct dry period 

 corresponding to the boreal of Sweden. The succession made out by 

 Nordmann (114a) is as follows: 



