The Botany of Iceland - 01.12.1914, Side 43

PHYSICAL GEOGRAPHY
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its surface. The Katla eruption, in tliis way, converted thickly in-
habited and fertile tracts into deserts, and in 1362 Öræfajökull de-
stroyed, in the same \vay, two parishes, sweeping away forty fartn-
steads with their inhabitants and live-stock and all else, out into
the sea.
The best-known Icelandic volcano is Hekla. It has been the
scene of 21 eruptions during historic times; next in importance
comes the glacier-volcano Katla of which 13 eruptions are recorded.
Fig. 11. Kverkfjöll, a volcano on the northern edge of Vatnajökull; seen from Hvannalindir.
(Phot. J. P. Koch.)
Submarine eruptions have taken place some ten to twelve times near
Eldeyjar off Reykjanes, whereby new islands have had their origin;
but these have disappeared again. Several volcanoes are present
beneath the ice-cap of Vatnajökull, but the foci of eruption are not
known for certain. During the last two centuries, from 30 to 40
eruptions have been recorded from the snow-fields of Vatnajökull.
During several of these eruptions the snow and ice on Skeiðarár-
jökull, on the southern side, partially melted, and enormous torrents
of water were discharged. Occasionally Brúarjökull, on the northern
side, has been very active. On Reykjanes there are numerous pre-
historic volcanoes and rows of craters, and in three or four places
eruptions have taken place since there have been settlements on