JOKULLS 
A great part of the highlands is covered with perpetual snow (jok- 
ulls) which occupies upwards of 14 000 square kilometres, or a little 
more than 13 per cent. of the total area. Largest of all the j6kulls is 
‘he Vatnajokull in the south-eastern corner of the country, extending 
over 8500 square kilometres. There are other large jdkulls in the in- 
terior (Hofsjokull, Langjékull), besides a number of high ice-capped 
mountains here and there near the coast, the most prominent being 
Eyjafiallaiékull and Mprdalsjékull in the south. The height of the 
snow line at Hornstrandir (in the north-west) is only 650 metres a- 
bove the level of the sea, while in the east, north of Vatnaiokull, it 
ascends to 1250 metres. 
VOLCANOES AND ERUPTIONS 
Iceland is thickly studded with extinct and active volcanoes. During 
the 1050 years it has been inhabited, over 20 volcanoes have had 
eruptions, some of them repeatedly, so that more than 100 eruptions 
are now on record. The best known of these volcanoes is Mount 
Hekla which has had 22 eruptions within historic times. Most of the 
volcanic mountains are situated in the south, whence a chain of them 
extends northward across the eastern part of the highlands to the 
Mpvatn (Midgewater) in the north. -- These frequent eruptions have 
sometimes caused a great deal of damage, though neither so often 
nor to such an extent as might have been expected. This is because 
the active volcanoes are in the interior wildernesses of the country 
and for the most part far from human habitation. The greatest devas- 
tation on record was caused by the Skaft (or Laki) eruption in 1783, 
when the lava flood laid a number of farms in ruins and showers of 
ashes covered the country far and wide, destroying vegetation and 
poisoning the air, and thus giving a terrible blow to Icelandic farming. 
When ice-capped mountains erupt, the jskull partly melts, and then 
bursts, and an enormous flood of water, carrying huge blocks of ice, 
comes tearing down the mountain-side, sweeping everything before it, 
and turning whole districts into deserts. The floods are called Jokul- 
hlaup (Gokull bursts). 
HOT SPRINGS 
In close connexion with volcanoes and volcanic activity are the Hot 
Springs (hverar), of which there is a great number in Iceland, scattered all