198 THORODDSEN 



rivers, so that no vegetation can thrive here. Below the southern 

 edge of Vatnajokull the farmsteads are therefore confined to oases 

 separated from one another by gravel-deserts and swollen glacier- 

 rivers. In many places the people have been obliged to move their 

 houses up on the mountain sides in order to avoid inundations 

 caused by the glacier-waters, and here the mountain-sides facing 

 south are covered with a luxuriant plant-growth, while the level 

 country below is devoid of vegetation. The sandy tracts have 

 different names, such as Breidamerkursandur , Skeidararsandur, 

 Brunasandur, Myrdalssandur, Solheimasandur, etc. Of these the 

 largest is Skei5ararsandur (about 900 square km.), and taken to- 

 gether they cover an area of about 2700 square km. Between L6- 

 magnupur and Myrdalsjokull the lowland becomes broader and is 

 covered by extensive lava-fields, blown sand, gravel and volcanic 

 ashes, as large volcanoes occur in the neighbourhood. The largest 

 area of low land in Iceland lies between Eyjafjallajokull and the 

 peninsula of Reykjanes and is about 4000 square km. in extent; it 

 is hemmed in by tuff-mountains which in many places fall abruptly 

 towards the plain. The lowest part of the lowland is only slightly 

 raised above sea-level, but it rises gradually towards the interior 

 where it ultimatelv branches off into different valleys; near Geysir 



*/ . /' 



it reaches its greatest height above sea-level, about 150 metres. The 

 low land is not flat everywhere, some parts of it are hilly, and a 

 few isolated mountains also rise from the plain. West of Hekla the 

 lowland, by means of a gentle rise, is in direct connection with 

 the interior plateau, to the great danger of the inhabited districts, as 

 the blown sand, volcanic ashes and pumice dust which cover large 

 areas of the interior have thereby free access to the lowlands; there- 

 fore, in these regions, during north-westerly storms, large tracts of 

 grass-covered and inhabited land have been overwhelmed in the 

 course of time. The lowlands consist chiefly of grassland, and no- 

 where in Iceland do farmsteads occur so closely together as here, 

 these districts being well-suited to cattle -rearing. Three very well- 

 supplied rivers run through the lowland, viz. Markarfljot with a 

 large delta-land (Landeyjar), Thjorsa and Olfusa, and besides these 

 there are many smaller ones. The eastern part east of Thjorsa is 

 called RangarvallasVsla, the western Arnessysla. At the head of Faxa- 

 floi there is another low area (about 1000 square km.) which on 

 an average has a height of only 20 30 metres. It is bounded by 

 steep, basalt mountains which are arranged in a semicircle around 



