BASALTIC FORMATION IN ICELAND. 99 



coloured rhyolites reappear in all the mountains at a high level as 

 far as Akreyri. 



Hop. 



A few miles south of Godalir, at the angle formed by the first 

 tributary to that river on its left bank, the section has been cut 

 through by the stream, and forms a perpendicular bank 12 feet high, 

 in Avhich are over twenty layers of lignite separated by gritty marls 

 and ferruginous bands, crowded with vegetable matter, Avith a soft 

 sandstone at base, similar in appearance to that of Husavik. At 

 12 feet a bed of lignite composed of compressed tree-trunks occurs, 

 and then another, 3 feet thick. The bank then slopes at an angle 

 of 30° for a distance of 60 feet, still abounding in lignitic matter, 

 when it is concealed by the greatly overhanging remnant of an old 

 moraine. On the opposite, or south bank, the same beds are capped 

 by columnar basalt. The plants again proved to be nothing but 

 rush-like monocotyledonous debris, with seeds, and probably remains 

 of Chara. The dip shown in both exposures (S.E, and N.) is 9°, and 

 the formation is probably extensive. The diameter of the largest 

 compressed trunk I extracted was 20 inches ; but this did not seem 

 to be the full width. There were many large trunks in the bed 

 of the stream, the branching of which suggested willows of large 

 dimensions. 



In this neighbourhood, about 7 miles from Hofsgil, a magnificent 

 section of over 1000 feet in depth can be studied (fig. 4). It forms 

 the side of one of the wildest conceivable gorges or canons. The 

 precipitous and even perpendicular sides are composed of more or 

 less columnar basalts, separated by partings of almost vermilion-red 

 earth, which has stained them a reddish purple. Where the sides 

 are not perpendicular, fragments of the old moraines, cold slaty 

 grey in colour, cling to them, weathered into fantastic shapes and 

 looking like ruined masonry. The torrent is just visible as pure 

 white foam at the bottom. The section here reproduced is of general 

 interest as showing the composition of the ordinary North Icelandic 

 mountain from top to bottom. Its upper part, as viewed from 

 across the gorge, forms a slope of from 50° to 60°, and overhangs a 

 tremendous precipice, so that it would not be accessible without 

 great danger. It is evidently similar to Sandafell, not many miles 

 distant ; and that the black band is really lignite is apparent from 

 my subsequently picking up pieces in the bed of the river. 



This gorge was evidently at one time filled in solid with Boulder- 

 clay or moraine, and enormous masses of rolled stones are spread 

 over the valley below. The stones have been arranged into sharj^ly 

 defined terraces. A river entering from a valley to the east had 

 accumulated an enormous mass of shingle, before the main river cut 

 its way through and cut down at least half the area to a level of 

 30 or 40 feet lower ; after which the rivers united and further 

 reduced it as much again, affording an instructive example of terrace- 

 formation. 



A better clue to the formation of parallel roads is furnished by a 



