Von Nidda on the Mineral Springs of Iceland. 221 



this valley there is a long line of hot springs, amounting to at 

 least 100 in number. Most of them are so insignificant, that 

 they would hardly be noticeable were it not for their clouds of 

 vapour ; but there are some which, after the Geyser and Strokr 

 in the Haukadal, are probably the most considerable in Iceland. 

 The springs of this valley have a great similarity to those of the 

 Haukadal, and may in like manner be divided into water and 

 gas springs. The water springs are filled with the clearest wa- 

 ter, which contains the same constituents as the water of the 

 Geyser. The incrustations consist of siliceous masses. Many 

 of these springs have periodical eruptions ; in the largest, the 

 periods of repose last five or six minutes, and the eruptions one 

 minute ; the jets of water rise to a height of from twenty to 

 thirty feet. 



The soil on which the gas springs are scattered, consists of 

 variously coloured clays. Sulphuretted hydrogen is the pre- 

 vailing gas evolved by the openings. At their edges we find 

 sulphur and some sulphuric salts. 



The tuffa and slaggy conglomerate mountains of the Guld- 

 bringesyssel, rise to the south of the Thingvalla lake, and, in- 

 cluding the middle of the tongue of land, form a steep rugged 

 chain to the west south-west. At Krisuvig, a deep transverse 

 valley cuts this chain. Beyond it the mountain range again 

 rises, but only to form a small ridge, which is again terminated 

 by a valley parallel to that of Krisuvig ; on the other side of 

 the second valley there is a ridge exactly similar to that between 

 the two valleys. There, however, the chain ends, and in its line 

 of continuation towards Cape Reikianaes, there are only iso- 

 lated rocky masses of the most peculiar forms. 



The valley of Krisuvig is important on account of its nume- 

 rous sulphurous springs, which are distributed over a consi- 

 derable flat tract, on its western rocky acclivity. So far as these 

 springs occur, the soil consists of clays of various tints. Only 

 a few of the openings are filled with muddy water. From all 

 of them there issue copious streams of steam mixed with sul- 

 phuretted hydrogen. The deposit of sulphur round these 

 springs is not inconsiderable ; it is from time to time collected, 

 and conveyed as an article of commerce to Reikiavig. Besides 



