Leonard Hawkes — Rock Stream in East Iceland. 101 



An interesting case of a landslide on to a glacier, which illustrates 

 what has prohahly taken place in the formation of the " Hraun", is 

 recorded by Fresh field from the Caucasus. " The Shikildi Glacier 

 presented itself as an advancing mound of huge blocks of grey 

 granite. ... In 1866 a noise as of thunder was heard by the 

 shepherds of the Baksan, and a great cloud of smoke or dust was 

 observed to issue from the recesses of the chain under Ushba. . . . 

 After a time it was ascertained that a great rock had crashed down 

 from the cliffs on the east side of the Shikildi Glacier. . . . We saw 

 next day the gap in the mountain side which had provided the 

 enormous masses now strewn over the lower glacier. . . . I never saw 

 such a goods-train of a glacier. . . . The immense size of the single 

 blocks and the complete burial of the ice under them are the features 

 which give their extraordinary character to the moraines of the 

 Shikildi" (10, pp. 137-8). It is interesting to note that in the Saga 

 relating the colonization of the Lodmundarfjord, circa 900 a.d., 

 mention is made of a landslide, and whilst this cannot refer to the 

 main mass of the " Hraun", there is little doubt that we here have 

 evidence that sliding has taken place in historic times. 1 



Many of the San Juan rock streams are regarded as landslides which 

 had no connexion with glaciers. It would be possible to regard 

 the " Hraun" as such, and the mounds in the Bardarstadadal as being- 

 formed from blocks transported by the shore ice-foot when this broke 

 up. But apart from the fact that the general aspect of the " Hraun " 

 is rather that of a moraine than a landslide, it is very probable that 

 under the severer climatic conditions giving rise to an ice-foot, 

 a glacier would exist in the Hraundal. Strictly the term " moraine " 

 should be used only of material which has been actually transported 

 by a glacier, rock debris which falls on to a stationary or retreating- 

 glacier being termed ordinary talus accumulations or landslide 

 material according to degree. There will be cases which stand near 

 the border-line between these two classes which will only be correctly 

 placed after very careful investigation. Whilst reserving a final 

 decision until the writer can make a more thorough examination, he 

 is inclined to the opinion that the " Hraun " has been transported to 

 some extent by a glacier and is therefore a true glacial moraine. 



The rejection of the " lava-flow " hypothesis removes an exception 

 to an important generalization, i.e. the post-Glacial instances of 

 volcanic activity in Iceland are confined to the Quaternary Formation 

 districts, so that the post-Glacial vulcanism is to be regarded as the 

 direct continuation of the Quaternary and not the Tertiary activity 

 (12, p. 18). It may be considered remarkable that the same 



1 " Lodmund the Old was the name of a man, and another was Beowolf his 

 sworn brother. They came to Iceland from Thule-ness in Vors. Lodmund 

 cast his porch-pillars overboard while he was at sea, and said that he would 

 settle where they were drifted ashore. And the sworn-brethren made East-frith, 

 and Lodmund took in settlement Lodmund-frith, and dwelt there three 

 winters. Then he heard of his porch-pillars being in the south of the country. 

 And with that he put on board his ship all that he had. . . . And when he 

 had been a little while, there was a great rumbling noise, and they saw a great 

 earth-slip fall upon the homestead which Lodmund had set up and dwelt in." — 

 Landndmabdc, iv, 9 (11). 



