132 



The Glacial Theory. 



tinned to observe the erratic phenomenon in the Vosges ; MM. Max 

 Braun, and Du Rocher have noticed it in the Pyrenees ; and I myself 

 have done so in the Black Forest. The Swiss and French Jura has 

 in this respect been made the object of continued study by MM. 

 Gressly, Guyot, and Desor, who have proved that the erratic blocks 

 of the Alps extend far beyond the limits assigned them by MM. de 

 Buch and Charpentier ; and, lastly, I have discovered erratic blocks, 

 accompanied by polished and scratched surfaces, in a host of loca- 

 lities in the Alps, where they had not previously been known to exist. 



" The great phenomena of the north, although attributed to other 

 causes, do not the less belong to the same subject; and, since the 

 investigations of MM. Alexander Brongniart and Sefstrom, they have 

 been made the object of continued researches by MM. Bothlingk, 

 Nordenskiold, Eichwald, Durocher, Robert, Martins, Murchison, De 

 Verneuil, and Kaiserling. Finally, the American geologists, also, 

 have very recently noticed a vast net-work of polished rocks and 

 erratic blocks in the United States. 



" But it is more particularly in Great Britain that the most unex- 

 pected discoveries have been made. Who could have supposed that 

 in these islands, equally remote from the glaciers of the Alps and the 

 ice of the north, traces of the action of ice should have been found ! 

 And, nevertheless, all the phenomena which indicate the former 

 existence of glaciers are there just as evident, and just as well pre- 

 served, as in the neighbourhood of the glaciers of the present day. 

 England likewise, — thanks to the activity and the zeal of her savans 

 — already possesses quite a literature on the subject of glaciers; 

 and it would be necessary for me to cite the names of most of the 

 geologists of that country, were I to mention all the individuals 

 there who have occupied themselves vvdth this question. 



" The purely theoretical part of the erratic phenomenon has also 

 attracted much attention ; and the discussions to which it has given 

 rise in many places, and particularly in the Geological Society of 

 France, have contributed, on their part, to render the study still 

 more interesting, by connecting it with the great problems of the 

 cosmic system."* 



Edinb. New Phil. Jom-n. No. 66, p. 218. 



