Frof. J. W. Spencer — Glacier- erosion in Norway. 167 



Stenocarpus, a purely Australian genus, as if to impress the clanger 

 of prematurely drawing inferences. Not deep below we have another 

 completely diiferent tropical flora on the Alum Bay horizon, with 

 scarcely a type of plant in common to the horizon above ; and again, 

 separated in this district by only a few hundred feet, we might find 

 the characteristic flora of the Eeading beds with an utterly distinct 

 assemblage, indicative of a temperate climate. In face of such 

 amazing facts it is only possible to smile at the glib way in which 

 temperatures and comparisons for every little handful of fossil 

 plants are set out, and the physical features of the country which 

 bore them reconstructed. 



These remarks are not intended to discredit those who have 

 laboriously worked at the task of deciphering fossil floras. They 

 are simply meant to warn those who have to make use of the facts 

 arrived at, that the conclusions and the inductions drawn from them 

 are not based upon foundations as assured as those of other branches 

 of geology and paleeontology. They may or may not prove to be 

 wholly or partiall}'- correct, but what we had best do for the jDre- 

 sent is to abstain from theorizing, and to devote ourselves to tlie 

 work of deciphering, more especially those floras whose ages are 

 definitely stratigraphically known, and by friendly intercourse and 

 repeated comparisons of actual specimens, to ascertain beyond all 

 dispute that a species means one and the same plant to each individual 

 worker. 



If at the same time it could be agreed that new species should not 

 be founded on fragments so obscure and imperfect that no good 

 specific characters can be obtained from them ; that references to 

 genera founded only on resemblance of foliage should be distinguished 

 by a special termination ; and that fossil plants found to be still existing 

 should bear the name of the living plants ; the science would rapidly 

 command that consideration and respect to which its vast importance 

 so well entitles it. 



VI. — Notes on the Erosive Power of Glaciers, as seen in 



Norway. 



By Professor J. W. Spencer, M.A., Ph.D., F.G.S. 



1 DURING- last summer it was my good fortune to visit the threa 

 , largest snowfields in Norway, namely, Folgefond, at the head 

 of Hardangerfjord, in Southern Norway, whose area is 108 square 

 miles ; the Jostedalsfond, two degrees to the northward, and beyond 

 Sognefjord, whose area is 580 square miles, and the largest snow- 

 field in Europe ; and the Svartisen, of nearly equal area, extending 

 from just inside the Arctic Circle for 41 miles to the northward. All 

 of these snowfields send down glaciers to within from 50 to 1200 

 feet of the sea. These snowfields are not basins like those in the 

 Alps, but are mantles covering the tops of the plateaux from 3000 

 to 5000 feet or more above the tide, from which great canons sud- 

 denly descend to the sea, and extend themselves as fjords from 1000 

 to even 4000 feet in depth. 



