SURVIVAL OF PLANTS ON NUNATAKS IN NORWAY 277 



Phippsia algida is not found in the outer mountains either. Through my 

 investigations of the snow-bed vegetation of the Scandinavian mountains I 

 have observed that the extension of some communities varies from the 

 continental mountains to the coastal ones. The sociological structure, how- 

 ever, is strikingly identical. This means that the deciding factors are the dura- 

 tion of the snow cover and the soil conditions. In view of this, the absence of 

 Phippsia algida is remarkable. 



From Greenland we know that under certain conditions even nunataks 

 may harbor a comparatively rich flora. From this fact the following question 

 appears self-evident: Did inland nunataks also exist in Norway during the 

 Ice Age ? 



Dr. N. A. Sorensen treated this possibility in a paper published in 1949. 

 There is some disagreement regarding the position of the rim of the ice sheet 

 during the maximum of the glaciations. Thorough investigations have been 

 performed by the geologist Undas (1938, 1942). Taking into account his 

 opinion of the ice border and further on the known normal gradient of a 

 large ice-mass, a number of mountains in the district of More must evidently 

 have been nunataks. Furthermore, there is good reason to believe that some 

 of these nunataks offered the plants very tolerable living conditions. Ex- 

 periences from Greenland have revealed that a "suitable" nunatak must 

 consist of loose rocks and moreover there must be south-facing slopes 

 strongly exposed to the heat of the sun. 



I want to draw attention to a certain area in the Trollheimen where I 

 (at the start together with Dr. N. A. Sorensen) have had the opportunity to 

 perform some investigations. The area in question is Gjevilvasskammene 

 Mts. on the north side of Lake Gjevilvatnet (Fig. 19). From the altitude at 

 this lake of 663 m, the mountains ascend with steep south-facing slopes and 

 precipices to an elevation of 1640 m. The effect of this exposure is a growth 

 period about one month longer than is normal for this area. 



The mountains are built up by loose schists, mainly mica schist. West of the 

 Gjevilvasskammene Mts. the elevation of the lowest passes to the nearest 

 fjords varies from 800 to 950 m. With an ice border as proposed by Undas 

 {he. cit.) and a normal gradient of the ice, the height of the ice front and the 

 rise of the land cannot have permitted an ice level in the Gjevilvasskammene 

 Mts. higher than about 1350 m. This agrees very well with the observations 

 made by the geologist A. Gronlie (1950) indicating an ice level of 1300-1350 m 

 for this area. Other geologists are of a different opinion, maintaining that ice 

 covered all the mountains in the Trollheimen area. 



Some peculiar soil layers constitute a special phenomenon to be found 

 situated on the tops and highest ridges of these mountains. Apparently 

 these layers are now subject to heavy wind erosion (cf. Figs. 20, 21). Several 

 geologists have examined the layers, and it has now been sufficiently demon- 

 strated that they consist of soil disintegrated in situ. By means of X-ray 



