PHYSICAL GEOGRAPHY 239 



lower level, is sheltered by several high mountains and has more- 

 over a rich fishery in Myvatn. The district of Fjallasveit is chiefly 

 covered with blown sand, and the plants growing on the sand-dunes 

 and sandy flats, viz. Elymus arenarius, Salix glauca and S. lanata 

 and Carex incur ua, serve as fodder for the sheep, which thrive well. 

 These plants are cut and gathered during autumn for winter-use. 

 It is, however, difficult to keep cow r s; and on account of the weather, 

 neither potatoes nor root-crops will thrive. The climate is also far 

 more severe than at the coast; the annual mean temperature in 

 Modrudalur is 0.8 C. In these districts the snow-line has a 

 height of 1300 1400 metres above sea-level, and the highest limit 

 at which habitations occur is 530 metres. On the north-w T estern 

 peninsula, to the extreme north the habitation-limit occurs at only 

 80 metres above sea-level, and the snow-line at 400 metres; more 

 to the south, on the same peninsula, at about 130 metres, and the 

 sno\v-line at 650 metres. For comparison with the height of the 

 snow-lines given above I give in the following pages a list of the 

 inhabited farmsteads situated at the highest levels in the different 

 parts of the country, because they give an indication of the limit 

 of the more densely plant-covered, inhabited country upw r ards to- 

 wards the w r ide expanses, poor in plant-life, in the interior. The 

 settlements in the uppermost valleys and in some parts of the 

 plateau are by no means fixed ; in years when severe weather occurs, 

 with cold and damp summers, some of these farmsteads are aban- 

 doned, but are again inhabited when more favourable w r eather sets 

 in. The areas above the populated districts, between these and the 

 desert proper, are too poor in plant-life to be inhabited, but they 

 are of great importance as summer-pastures for sheep and ponies. 



Heights of the uppermost farmsteads above sea-level in metres. 



Upon the northwestern peninsula. 



Smidjuvik SE. of Cape Nord 80 metres 



Skogar in Mosdal at Arnarfjordur. . . . 82 

 Hlidarsel at Steingrimsfjordur 128 



Near Faxafloi. 



Fornihvammur in Nordurardal 170 metres 



Gilsbakki in Hvitarsida 175 



Fljotstunga 232 



Kalmannstunga 218 



Haell in Flokadal. 174 



