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principal phenomena attending eruptions of this volcano were 

 stupendous floods of heated water, and the prodigious quantities of sand 

 ejected. It had, he believed, never been known to produce lava, but 

 upon the base of the mountain he found numerous ancient lava streams, 

 proving that at one time Katlugia was no exception to its neighbouring 

 volcanoes. The floods from Katlugia during eruptions had often 

 submerged a district of 280 square miles, continuing sometimes for 

 days, in spite of the rapid outflow to the sea. These floods were 

 produced not only by the melting of the snow at the time of eruption, 

 but in all probability by the bursting of large cavities in and beneath the. 

 mountain, in which water might have been for years accumulating. 

 This aqueous phenomenon was, however, by no means peculiar to 

 Katlugia, although it occurred on the largest scale, for during the 13th 

 and 14th centuries all the volcanoes in the south of Iceland erupted 

 water. 



The most extensive eruption that ever occurred in Europe during 

 historic times proceeded from the south-west portion of the Vatna, 

 named the Skaptar JokuU. This volcano had only been known to 

 have erupted upon that occasion, viz., A.D. 1783, when it produced 

 two of the most extensive lava streams in Europe, of which he would 

 speak presently. The volcanoes which erupted so violently in the 

 beginning of the present year, and one of which wrought such damage 

 in "the north of Iceland were-The Oskja-gia (or the chasm of the 

 oval casket) situated in the Dyngjufjoll mountains upon the north of 

 the Vatna, and a chasm some twelve miles in length which opened 

 in the Myvatos orcefl (or sandy desert of Myvatos). The first of these 

 was a triangular crater over five miles in circumference, formed, he 

 should be inclined to think, by three smaller craters blowing into one 

 another. It Avas situated in the south corner of the plain of Askja, in 

 the Dyngjufjoll mountains. This plain was situated at the height of 

 about 3,000 feet, and was shut in on all sides but one by semi-detached 

 sections of mountains, many of which had broken out in ancient times, 

 and by their insignificant lava streams had helped to swell the wide- 

 spread lava desert of the Odathahraun. The crater of Askja-gik was 

 bounded on the north by a wall of rock which descended in a sheer 

 precipice of some 200 feet from the level of the plain of Askja. It was 

 shut in upon the east and west sides by lofty mountains, some of 

 which roseto the height of 1,000 feet above the plain of Askja ; they 

 appeared shorn of their inner faces by the violence of the eruption, 



