530 PREHISTORIC EUROPE. 



peat, has been admirably worked out by Blytt, who is of opinion 

 that the evidence warrants him believing in at least three rainy 

 periods, when peat formed abundantly, separated by intervening 

 dry periods, during which the peat-mosses dried up and were 

 overgrown by forests. My observations in Scotland go a long 

 way to support Blytt's theory of alternating dry and rainy 

 epochs, but I cannot at present detect any evidence of more 

 than two rainy periods in postglacial times. The postglacial 

 period, however, was doubtless ushered in by cold and wet 

 conditions, during which the arctic-alpine flora migrated north 

 from the low grounds of Central Europe. The first rainy epoch 

 of Blytt would thus correspond with the close of the Glacial 

 Period and the commencement of the Postglacial Period, the 

 two succeeding rainy epochs occurring in late postglacial and 

 recent times. 



The reader will not understand me to mean that the forests 

 of North-western Europe were completely overthrown and buried 

 in growing peat during each successive rainy period. There 

 seems no reason to doubt that many wide tracts continued to 

 support a forest-vegetation from the beginning of what we may 

 call the first Age of Forests down to historical times. All that 

 is sought to be maintained is simply this, that during the recur- 

 rent wet periods the forests were restricted in their horizontal 

 and vertical range. They disappeared from wide tracts in the 

 low grounds where they had formerly flourished, and were no 

 longer able to sustain themselves at the higher elevations of the 

 land. It must further be admitted that many of the ancient 

 forests owe their overthrow to the hand of man. In our own 

 country and in Germany the Eomans are very generally credited 

 with this work of destruction, but the peat-bogs with buried 

 trees which can be proved to date down to so recent a period 

 are much less numerous than has been supposed. The mere 

 occurrence of Eoman relics in peat is no proof that the trees 

 which underlie that peat were growing in Eoman times. Scot- 

 tish antiquarians have gone on repeating one after the other the 

 tale of Eoman destructiveness, and have pointed to the presence 



