10 



A. BL YTT. 



[No. 8. 



the wateiy bog. tbeir remains being buried by the growing layer 

 of peat. 



In this manner the striictiire of the peat confirms the con- 

 clusion to which the distribution of the flora pointed. and if we 

 take the fossil plants and marine shells to our aid, we may 

 explain the gaps in the extension of the species withont assnm- 

 ing long transports of seeds. 



In the fresh water clay of Scania and Seeland. Prof. Xathorst 

 h is disco vered numerous remnants of arctic plants. This clay 

 lies below the peat. When it was deposited in the cavities of 

 tlie old bottom nioraines of the inland-ice, not only the dwarf 

 birch. but even hj^perborean plants, such as Salix polaris and 

 others flourished in the sonthernmost parts of Scandinavia: there- 

 fore the arctic flora was the first which immigrated into our 

 land. It entered whilst the climate was very severe. But 

 the climate became milder and more moist. The peat began to 

 form; the» the aspen and birch entered and, later on, under 

 varying conditions of moisture, the fir and the spruce, with the flora 

 of the mountain- and forest-glens, a seiies of species which have not 

 yet been mentioned, viz. Mulgedium and Aconitum, man}^ great 

 ferns and grasses, wood Geraniums, and Lychnis &c. But the cli- 

 mate became warmer and warmer; and finally the foliferous trees, 

 more sensitive to cold entered, viz. the hazel, the lime, the ash, 

 the oak, the maple, and a number of others from warmer regions. 

 In the province of Bohus quantities of stones of sw^eet cherries 

 are found in many places, in peat, where this tree is now extinct; 

 and in the Norwegian peat bogs hazel nuts are very frequent 

 in a certain layer, not only in the interior of the great conife- 

 rous forests, where not a single hazel tree is found, but even in 

 heathery woodless coast-lands. It will, therefore, be seen that 

 the hazel and the sweet cherry were then very plentiful and 

 from this we may justly conclude that the trees and shrubs and 

 herbs which thrive in their company were also once far more 

 plentiful than at present. It is this flora which has found an 

 asylum in the above mentioned screes. 



Following the period when Southern Norway was covered 



