GLA CIAL SUCCESSION IN NOR WAY. 1 3 5 



epiglacial lakes without filling them up in any considerable 

 degree. The ice melted so speedily away, and the crust swelled 

 up so fast, that the deposits of the rivers just below the epi- 

 glacial terrace level are very small. This could only occur with 

 a climate more genial than the present in which an existing 

 glacier as great as the epiglacial land ice would certainly assert 

 itself with success. 



We must suppose a considerable uplift of the snow line in 

 this time which followed the epiglacial period, and which I shall 

 call the Boreal period. Such a genial climate in early post- 

 glacial time we are forced to assume also on biological reasons. 

 On the warm valley sides in the western interior fjords, we find 

 many plants which can only prosper in a temperature more 

 than 2° C. higher than now prevails in the intervening tract 

 across which they must necessarily have immigrated. On the 

 southwestern coast flourished a vegetation almost like the Irish 

 coast flora, but separated from its main habitat by a temperature 

 perhaps 4° C. lower in January than it will bear. These Boreal and 

 Atlantic plants can only have spread to their isolated places in 

 Norway in a climate some 3° C. warmer than the present. That 

 this warmer time did occur in early post-glacial time is again 

 proved by the stratification in the peats, where the plants most 

 susceptible of cold (ash, oak, etc.) are found in the deepest 

 layer or rather on the bottom itself — this also in places on the 

 coast and in the mountains where now no forest tree grows. 



These 3-4° C. recorded by the vegetation would certainly 

 have raised the snow line, which now is 1200 to 1800 meters above 

 the sea in Norway, above almost the whole epiglacial ice sheet, 

 which nowhere attained 2000 meters. The great inland ice must 

 then have become a dead glacier, and must have melted rapidly, 

 especially from the margins. The last remnants of it might be 

 supposed to have been situated near its maximum elevation, i.e., 

 near the ice shed. This lay, as explained above, in deuterogla- 

 cial time at some distance to the southeast of the land watershed, 

 as the many boulders in the upper eastern valleys which were 

 transported upwards prove. The ice remnant is then to be 



