On (he Glaciers and Climate of Iceland. 135 



of Etna, in the year 1669, formed a stone-dike in the sea ; 

 and, indeed, should the case above supposed occur, experience 

 will certainly shew the contrary. 



Many other reasons which we derive from that peculiar 

 configuration of the streaks, already described, namely, their 

 mutual intersection, oppose quite as decidedly the supposi- 

 tion of a universal prevalence of glaciers in Iceland. 



Forchhammer, some years ago, pointed out the true origin 

 of the streaked rocks, in a valuable paper on the Formation 

 of Boulders, and Diluvial Scratches, in Sweden and Den- 

 mark.* According to later investigations made by him, of 

 which some have not yet been published, and which he had 

 the goodness to communicate to me, it appears indubitable 

 that the formation of the streaked rocks continues to go on 

 up to the present time-t A winter residence in Iceland or 

 Scandinavia would probably introduce an attentive observer 

 into the workshop of this very simple, but often misunder- 

 stood phenomenon. 



My friend, Frapoli, to whose unwearied zeal we are in- 

 debted for very valuable discoveries in the geology of our native 

 country (Germany), has lately, during his travels in Norway 

 and Sweden, on a part of which I accompanied him immediately 

 after ray departure from Iceland, made the striated rocks of 

 these countries a subject of very extensive and profound in- 

 vestigations, which must set aside any doubt that may still 

 prevail with regard to this question. He had also the good- 

 ness occasionally to point out to me various phenomena, 

 bearing on the subject, which are better exhibited on the 



* Poggendorff's Annalen, Second Series, vol. xxviii. 



t Thus Professor Forchhammer communicated to mo an interesting occur- 

 rence which lately presented itself on the coast of North Zeeland, and which 

 serves as a clue to assist in explaining the formation of the striated rocks. In 

 the winter of tlie year 1844, the ice had formed itself round a granite block, 

 sixty or eighty cubic feet in magnitude; and, on the approach of spring, this 

 block was put in motion along with the retiring ice. The pressure which it 

 produced on the almost horizontal sandy bank was so great, that a furrow was 

 cut which, in the following .September, after the course of six months, had not 

 completely disappeared. IJy the rubbing of such a block on a hard bottom, 

 there is no doubt that smoothed or striated surfaces would be occasioned of the 

 same kind that we liavc so often observed in Iceland uud Scandinavia. 



