78 REPORT — 1855. 



been evidently formed by gradual deposition from the water, and a mound round 

 them has in like manner been formed 30 feet high, and extending in various direc- 

 tions to distances of 80, 100 or 120 feet." The great eruptions, which by theodo- 

 hte he ascertained to rise 96 feet, took place every two hours, and lasted 15 to 20 

 minutes. The Strokr he states to be G feet 10 inches in diameter, and its eruption 

 to be much more columnar than that of the Geyser, and rising to the height of 132 

 feet. In 1810 Sir George Mackenzie found the pipe 60 feet deep and 10 in diameter, 

 and its basin only 3 feet deep, and from 46 to 58 feet across — the configuration 

 of the latter in his time not being round, but indented, as it were, at one side. The 

 Geyser eruption he estimated as rising to 90 feet, and the periods of its action were 

 more frequent than now. The Strokr, Sir George says, played magnificently to the 

 height of 70 feet for half an hour at a time. Henderson, in 1815, who paid the 

 locality two visits, estimated the Geyser eruption at 150 feet, and that of the Strokr 

 as even higher than 200 feet. The French in 1836 made the depth of the Geyser 

 75^ feet, the breadth of the basin 52i, the height of its eruptions 105, and the dia- 

 meter of the pipe 16 feet. The Strokr they noticed to rise to the height of 92 feet, 

 and the diameter of its pipe they give at 8 feet, and its depth at 65 feet. 



Professor Bunsen, in 1846, who spent eleven days upon the locality, found the Gey- 

 ser about 66 feet deep, and estimated its eruption at 140 up to 177 feet. The Strokr, 

 he says, is 43 feet deep, and only 7 in diameter, and he estimated its eruption at 160 

 feet. Comparing these descriptions and measurements with each other and with 

 our own, it is pretty evident, that whether the intensity of the eruptions of these 

 Geysers be greater or less now than they have been during the past seventy years, they 

 assuredly have fallen off exceedingly, both in their frequency and in their duration. 

 No doubt the action is more powerful at one time than another, or at one season 

 than another ; indeed it is believed to be more so in damp and wet weather than 

 during dry seasons. The supply of water to the springs must vary, and the evapo- 

 ration at the surface, dependent on the currents of air, may also have its effect upon 

 their action. Still, that the quantity of water emitted from them on the whole is 

 much less than it once was, there can be no question. 



Sir John Stanley found the great eruptions of the Geyser take place every two 

 hours. Henderson, in 1815, says that the Geyser erupted in the most imposing 

 manner every six hours. We waited twenty-seven hours before anything of the kind 

 occurred ; and the eruptions of the Strokr, which Sir George Mackenzie gazed upon for 

 half an hour at a time, never now last above eight or ten minutes. Another obvious 

 change has been going forward, and is still progressing, in the mound of the Geyser, 

 arising from the rapid deposit of siliceous matter upon its sides. The edge of this mound 

 forms the rim of the circular cup, which Sir John Stanley and Sir George Mackenzie 

 both describe as about 60 feet across. This has now extended, still however in a 

 nearly circular form, to no less than 68 by 72, and the size and bulk of the mound 

 must have correspondingly increased. On the whole, such decided changes upon the 

 aspect of these Haukedalr Geysers leave little doubt that their action is becoming 

 rapidly weaker, and that the time may not be far distant when their forces, like those 

 of Hecla in the vicinity, will become nearly quiescent. There are other similar hot 

 springs in the island, especially to the north, which are known, on the contrary, to 

 be steadily increasing ; and I am sanguine of bavmg it in my power shortly to place 

 in the hands of our scientific men a detailed account of some of these to us hitherto 

 almost unknown Geysers in Iceland. 



On the Superficial Deposits laid open hxj the Cuttitigs on the Inverness and 

 Nairn Railroad. By George Anderson. 



On tlie recent Discovery of Ichthyolites and Crustacea in the Tilestones of 

 Kington, Herefordshire. By Richard Banks. Communicated by the 

 President. 



The discovery of fossil fishes and minerals, highly illustrative portions of the 

 crustacean Pterygohis, by Mr. R. Banks, was adverted to by Sir R. Murchison, the 

 detailed description of which was referred to the Geological Society of London. 



