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waters which washed the south outlying hills of the Vatna receded to 

 their present limit. The Vatna JokuU comprised by far the most 

 important mountain section in Iceland, and a far greater area was 

 covered by its snows than could be occupied by the sum of all the 

 remaining snow-clad mountains in Iceland. As might be supposed, 

 at least half the river water of Iceland flowed either directly or 

 indirecdy from the Vatna JokuU, either issuing in torrents from the 

 extremity of its glaciers, or after filtering for long distances through 

 the loose and cavernous ground, appearing as land springs at a lower 

 elevation. 



The rocks of the Vatna, as far as he had had an opportunity of 

 judging, were purely and simply the product of this very remarkable 

 cluster of volcanoes, which had piled up layer after layer of ash, sand, 

 and agglomerate, until a mountain heap was formed of such a height 

 that it allowed snow and ice to accumulate upon it to such an extent 

 as to render the summer's warmth quite inadequate to remove it. 

 This vast snow pile then grew of its own accord, and glaciers com- 

 menced to creep down the sides of the barren mountains upon which 

 it rested. Volcanoes continued to erupt, but the effect of their fires 

 upon the accumulating snow must have been purely local and limited 

 in the extreme, for volcanic productions were the worst possible 

 conductors of heat, and he should imagine that a lava stream, unless 

 it were of gigantic proportions, conducted itself beneath the profound 

 snows of the Vatna, much as a lava stream would beneath the sea, 

 without producing any very violent commotion. Thus this vast 

 mountain mass was accumulated, growing with each succeeding 

 winter and each eruption. The Vatna JokuU rose by a very gradual 

 slope upon the south, and it was not until more than thirty miles of 

 snow fields had been traversed that the highest part of the Vatna, viz., 

 6,150 feet, could be reached from that direction. 



He had at present omitted any mention of the snow line in 

 Iceland ; this was on account of its variable nature, incidental to local 

 causes. Thus upon the Vatna we had the snow line much lower upon 

 its southern than northern slopes, the cause of which he would consider 

 presently. Of late years the volcanic forces of Iceland appeared to 

 have retreated to the Vatna JokuU and its immediate neighbourhood, 

 and volcanic eruptions had been witnessed in force in several directions . 

 The KrerktjaU they found to be smoking and Oskja-gjk could only be 



