70 M. Chai'pcnticr un the Erratic Thcnumcua of the Xorth. 



mate. But it is probable that 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 om- most elevated 

 mountains. The snow, beyond the 70tli degree, from the im- 

 possibility of its transformation into glacier, must have corres- 

 ponded completely with the most elevated /lauts neces {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, were 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 trans- 

 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 mixlifications, however great they may have 

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

 mena.* 



* The isotlieiiiial lines, iind especially the isotlicral lines, must have 

 exercised a considerable iutlucnco on tiic formation and on the development 

 of the diluvian glacier of the North. It is, williont doubt, in the direction or 

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

 tion not reaching the 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, would be of gi'oat importance fur 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 geologic al 

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

 and acquire that scientific interest, it is indisiicnsable that the erratic for- 

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

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

 taincd, andcironeous conclusions deduced. 



