70 M. Cluirpcntior on the Erratic FhowDicua of the Xortk. 



mate. But it is probable tbat from the 70th degree the melt- 

 ing of the snow had nearly ceased, or, at least, that it was 

 scarcely more considerable than it now is on our most elevated 

 moimtains. The snow, beyond the 70th degree, from the im- 

 possibility of its transformation into glacier, must have corres- 

 ponded completely with the most elevated hauls netes (Essai, 

 § 3). The fact that the larger portion of the polar regions is 

 occupied by seas, is not opposed to this supposition ; for, if 

 these seas, as is very probable, wei^e then covered by ice, as 

 they are at the present day from the 80th degree, the snow 

 could rest there just as well as on solid land. 



Nor is there anything which obliges us to restrict the ti'ans- 

 formation of snow into ice to Scandinavia alone. On the 

 contrary, it is more probable that the conditions of climate 

 necessary for the transformation were to be found in the 

 whole zone, comprised between the 60"" and 70° parallel. This 

 supposition is supported by the existence of the erratic for- 

 mation in Siberia, and in the North of America. The isother- 

 mal, and particularly the isotheral lines, have, it is true, ma- 

 terially modified the northern limit of this zone of permanent 

 snow ; but these modifications, however great they may have 

 been, do not at all influence the theory of the erratic pheno- 

 mena.* 



* Tlie isotliernial lines, and especially tlie isotheral lines, must have 

 exercised a considerable influence on tlic formation and on the development 

 of the diluvian glacier of the North. It is, without doubt, in the direction or 

 course of these lines that wc must seek for the cause of the erratic forma- 

 tion not reaching tlio same parallel throughout the whole of the north ; 

 thus, for example, the limit of this formation advances much more to the 

 south in the north of Germany, than in Eussia and in Siberia. It is plain, 

 that the more these lines ascend to the north, the less could the glacier ad- 

 vance towards the south. The exact determination of the limit of the er- 

 ratic formation, Avould he of gi-eat importance for the physics of the globe ; 

 it would throw much light on the climatological condition of the north of 

 the northern hemisphere during the earliest periods of the present geological 

 epoch. But in order thai this investigation might accomplish its object, 

 and acquire that scientific interest, it is indispensable that tlie erratic for- 

 mation should be accurately distinguished from the diluvium, because, by 

 confounding these two formations, as is often done, false results arc ob' 

 taiucd, andcironcoutf conclusions deduced. 



