recent plantations of imported trees have taken place, abso- 
lutely prehistoric in that country. That age was succeeded 
by degrees by an age of oaks (Q. robur, sessiliflora, Smith). 
Above the oak layer appears a bed of beech trees — 
now the forest tree par excellence, of Denmark. Through- 
out the term of these three strata, the records so to speak 
of successive ages of pine, oak, and beech, the poplar 
( populus tremula L.) appears, while the white birch (betula 
alba L.) lies in the lower beds, and is succeeded above by 
the betula verrucosa L. which is the form now prevalent 
in Denmark. In Denmark these forest pits are considered 
the most ancient of the three peat or moss formations. The 
whole of these, according to M. Steenstrup, are full of 
relics of bygone races of men. He states that he believes 
that there is not a pillar a yard square of any moss in 
Denmark that would not yield some specimen of ancient 
handiwork. 
The forest pits do not at the bottom exhibit traces of. 
human presence, but amongst the pines objects of the stone 
age appear, proving the great antiquity of the primitive 
population of Denmark. M. Steenstrup himself took stone 
implements from under the stems of ancient pines. Pieces 
of wood cut (with the help of fire) also occur. 
It would seem that the age of bronze implements coin- 
cided with the oak era, and the age of iron, which falls 
within historic ken, with the still current period of the 
beech. 
In the British Islands the forest pits have not hitherto 
been distinguished. In Ireland the peat bogs prevail over 
a large extent of country, and the boggy levels also occur. 
Each has furnished a large store of stone instruments, and 
occasionally objects of wood of greater or less antiquity. 
In England stone implements are not unfrequently found 
in the'low level tracts of river valleys. 
The peat bogs, passing under the name of Mosses, are of 
