460 



GLACIERS IN SOUTffFf'X 

 NORWAY 



I N the 'ifcond pnri m iu r^ms 

 Musfutfis Aarholi for i<)ii, 

 J. Krkslnd publishes in (jf-rman a 

 description of the gimicr region 

 of southern Norway, accompanied 

 by thirty-four illustrations. 'Ihi- 

 paper is intended to serve as ;i 

 j<uidi> to visitors, and does not 

 discuss questions of glacial erosion 

 or the origin of landscajH'-forms. 

 The Jostedalsbr.-u (Kig. i) north 

 of the S»)gnefjord has a surface of 

 855 square kilometres, and fur- 

 nishes an excellent type of the 

 plateau-snowfield, from which 

 glaciers fall, rather than creep, 

 into the valleys round about. .\s 

 one views a high field of this kind 

 from a distance, the contrast witli 

 the limited snow-basins of the 

 Alps is immediately apparent. 

 Round about it, isolated glaciers 

 lie in cirques, which have been no 

 doubt carved out since the time 

 when the main ice spread farther 

 over hill and dale. 



Regenerated glaciers occur at 

 the feet of steep places on the 

 plateau ridge, and one of these, 

 the Suphellebrac, extends down to 

 a level of 50 metres above the se.i. 

 The author directs attention to ii^ 

 banded structure, which here must 

 be attributed to flow under 

 pressure, since any such structure 

 due to successive deposition of 

 snow on the n^v6-field would be 

 obliterated as the ice falls over the 

 rock-face (Fig. 2). The terminal 

 block-moraines of the Bciiuni 

 Glacier are referred to, and arc 

 so well marked as to have de- 

 served a photograph. 



.As a glacier retreats, its valley 

 may become filled up by detritus 

 washed out by the water from flic 

 melting ice. An alluvial flat 

 arises, over which the streams 

 meander, frequently changing 

 their courses, and these streams- 

 have no relation to the magnitude 

 of the original valley. When the 

 ice finally passes away, under 

 warmer climatic conditions, the 

 streams may almost disappear. 

 Where ice-erosion has been power- 

 ful, dry valleys filled by alluvium 

 may remain, in the formation of 

 which water has played very little 

 part. This consideration is sug- 

 gested by the view of the Tuns- 

 berg valley (Fig. 3), stretchin.ij 

 from the foot of the longest glacier 

 in Norway, one of the tongues 

 from the east side of the massive 

 Jostedalsbr<Te. The author records 

 (p. 26) that the rate of infilling in 

 these valleys is so rapid that 

 vegetation does not gather on the 

 stones, and that dwellings have to 

 be shifted, owing to the rise of 

 glacial waters on the growing 

 alluvial floor. The cattle-paths 

 must similarly be moved upwards 

 on the valley-sides. The retreat of 

 the glaciers during the last 150 

 years has left smooth steep rocks 

 exposed in many cases, the scene^- 

 of former ice-cascades, and the 



NO. 2205, VOL. 88] 



NATURE 



[February i. 1912 



Vu. 



the snow-plate.'i 



I'he 



U'hel ebra;. a regenerated glacier on the margin of the Jostedalsbrx. 



