CHAP. ii. WORKS OP ART IN DANISH PEAT-MOSSES. 9 



ten to thirty feet, have been formed in hollows or depres 

 sions in the northern drift or boulder formation hereafter to 

 be described. The lowest stratum, two to three feet thick, 

 consists of swamp-peat composed chiefly of moss or sphagnum, 

 above which lies another growth of peat, not made up 

 exclusively of aquatic or swamp plants. Around the borders 

 of the bogs, and at various depths in them, lie trunks of trees, 

 especially of the Scotch fir (Pinus sylvestris), often three 

 feet in diameter, which must have grown on the margin of 

 the peat-mosses, and have frequently fallen into them. 

 This tree is not now, nor has ever been in historical times, a 

 native of the Danish Islands, and when introduced there has 

 not thriven ; yet it was evidently indigenous in the human 

 period, for Steenstrup has taken out witji his own hands a 

 flint instrument from below a buried trunk of one of these 

 pines. It appears clear that the same Scotch fir was after 

 wards supplanted by the sessile variety of the common oak, 

 of which many prostrate trunks occur in the peat at higher 

 levels than the pines ; and still higher the pedunculated 

 variety of the same oak (Quercus Robur L.) occurs with the 

 alder, birch (Betula verrucosa Ehrh.), and hazel. The oak 

 has now in its turn been almost superseded in Denmark by the 

 common beech. Other trees, such as the white birch (Betula 

 alba), characterise the lower part of the bogs, and disappear 

 from the higher ; while others again, like the aspen (Populus 

 tremula), occur at all levels, and still flourish in Denmark. 

 All the land and fresh-water shells, and all the mammalia as 

 well as the plants, whose remains occur buried in the 

 Danish peat, are of recent species. 



It has been stated, that a stone implement was found 

 under a buried Scotch fir at a great depth in the peat. By 

 collecting and studying a vast variety of such implements, 

 and other articles of human workmanship preserved in peat 

 and in sand-dunes on the coast, as also in certain shell- 

 mounds of the aborigines presently to be described, the 



