SOOIETY OF THE UNIVERSITY OF ABERDEEN. 41 



of these mosses the prevailing tree is the beech, which flourishes 

 there at this day in great forests, and has done so as far back as 

 history goes. Under this upper section of beech a number of oak 

 trees take their place, while in the lowest section the Scots fir 

 predominates. The conclusion to which this investigation points is 

 that there have been, broadly speaking, three periods in which forests 

 of these trees successively prevailed extensively over the country, 

 first the fir, then the oak, and lastly the beech, and as this last still 

 prevails, and has been known to prevail for the last two thousand 

 years or more, how much longer we do not know, it is inferred that 

 the other two must have each embraced a period quite as long, if 

 not longer, and this is substantiated by observations of the rate at 

 which peat mosses grow. Below and amongst the fir layer, the 

 lowest of the three layers, flint instruments were found buried in the 

 peat at great depths. 



By collecting and studying a great variety of such implements 

 and other articles of human workmanship preserved in peat, and in 

 sand dunes and shell mounds along the coast, the Danish and Swedish 

 antiquaries have succeeded in establishing a chronological succession 

 of periods which they have called the ages of Stone, of Bronze and 

 of Iron, named from the materials which have each in their turn served 

 for the fabrication of implements. 



The age of Stone in Denmark coincides with the period of the 

 Scots fir, and in part at least with that of the oak. But a con- 

 siderable portion of the oak period coincides with the age of Bronze, 

 for swords and shields of that metal, now in the Museum of Copen- 

 hagen, have been taken out of peat in which oaks abound. The age 

 of Iron corresponds more nearly with that of the beech tree. The 

 number and variety of objects belonging to the Bronze period indicate 

 its long duration, as they do the progress in the arts, implied by the 

 rudeness of the earlier tools, which were often mere copies of the 

 stone implements preceding them, as contrasted with the more skil- 

 fully worked weapons of a later stage of the same period. 



It has been supposed that an age of Copper intervened between 



