52 GEOLOGICAL MEMOIRS. 



even to inhabited places, where the temperature of the air sets limits 

 to its further progress, and where the portion destroyed by melting 

 must be continually and rapidly renewed from above." From these 

 essential conditions in the formation of glaciers it evidently results, 

 that the cause of their progress and sliding down into the valleys 

 must he sought, either altogether, or at least chiefly, towards their 

 origin, and above the snow-line, never in the ice-masses themselves, 

 which in this respect are altogether passive. In this upper region 

 the pressure of the connected ice-masses operates, exactly as the pres- 

 sure on the Rossberg has pushed down a whole stratum of the moun- 

 tain, destroyed it, and covered half a canton with the giant-fragments ; 

 and this pressure is not destroyed in its progress, but increased, until 

 the temperature and smaller declination of the valley are able to 

 counterbalance the pressure of the mass. No glacier continues to 

 move, when the bottom of the valley on which it rests has a less in- 

 clination than 3° (Elie de Beaumont). No doubt large extended 

 masses of snow often appear in confined valleys below the snow-line ; 

 they m^ay even be changed into vaults of ice, as is so beautifully seen 

 in the ice-chapel not far from the Bartholomseus lake at Berchtesgad ; 

 only these masses never move ; they fill no valley like a long ribbon, 

 like a frozen cataract, — for they want the pressure from above, the 

 only thing that can move them downwards into the valley. 



M. Du Rocher has visited one of the three conical hills mentioned 

 by Scoresby ; he estimates it, from barometrical measurements on the 

 declivity, at 1185 feet high (385 metres); it is consequently higher 

 than Mount Misery ; and yet its steep acclivities were scarcely covered 

 with snovf ; just because the sides of this cone are so steep. The 

 violent winds do not allow the snow to rest on such abrupt slopes, 

 "says M. Du Rocher ; and the almost horizontal rays of the sun fall 

 nearly at right angles on the snow, though they touch the surface of 

 the island at a very low inclination. Besides, this volcanic-looking 

 cone consists, like all the other elevations on the island, of immense 

 blocks of carboniferous sandstone heaped one above the other. Yet 

 M. Du Rocher seems to have visited only the western side, and that 

 only for seven hours, from mid-day to eight in the evening. This 

 time may have been too short to draw the attention of the French 

 naturalist to the profusion of instructive organic forms which fills 

 this sandstone, and which Keilhau has collected with so much in- 

 dustry and care on the declivity of Mount Misery — at least the 

 figures of petrifactions in the work of Gaimard contain only those 

 observed in Spitzbergen, and even in Nova Zembla, but none from 

 Bear Island. 



The temperature of the air varied during Keilhau' s stay on the 

 island, in the middle of August, from 2\° to 4-^° R. (=37i° to 42° 

 Falir.) ; and on the west side of Nordhafen, at the base of a cliff ten 

 feet high, two running springs gave, the one 0*6° (33^° Fahr.), the 

 other 3-8° R. (40^° Fahr.); so that 2°— 3° R. (364°— 38|° Fahr.) 

 may be considered as the mean temperature of the surface in this 

 month, — a warmth sufficient to permit the lively growth of some 

 flowers and herbs. Among these the Cochlearia is the most distin- 



