Ancient Extent of the Glaciers of Chamonix. 55 



mountaineer how men of science had shewn, by means of 

 profound calculations, that the erratic blocks had been for- 

 merly transported by strong currents of water. To all this 

 Jean Perraudin could answer nothing, but he shook his head 

 with an air of doubt and incredulity. '* I am of opinion," he 

 said at length, " that the glaciers of our Alps were much 

 more extensive formerly than in the present day. The whole 

 of our valley, to a great height above the torrent of the 

 Drance has been filled by a vast glacier which descended as 

 far as Martigny, as is proved by blocks of rock found in the 

 neighbourhood of that town, and which are far too large to 

 be transported by water." In speaking thus, Perraudin 

 little suspected that he had made a great discovery, and 

 solved, by his own good sense, a problem which the genius 

 of the most celebrated geologists, furnished with all the re- 

 sources of science, had attempted without success. 



Fortunately the individual to whom he thus communicated 

 the result of his solitary observations was a practical man, 

 more interested in facts than theories. The hint the peasant 

 suggested to his mind developed itself freely, and the idea of 

 the ancient extension of glaciers beyond their present limits, 

 became, for twenty years, the constant object of his researches 

 and reflections. One of his friends, an engineer, M. Venetz, 

 had been led to entertain the same views from studying the 

 erratic blocks of the Valais. Lastly, in 1834, when his con- 

 viction was complete, and supported by numerous and irre- 

 sistible proofs, M. de Charpentier (for it was he who had 

 been Perraudin's confidant) brought forward his opinion at 

 the meeting of Swiss naturalists held at Lucerne. Like every 

 new idea, it was received with coldness, or treated with dis- 

 dain ; but, as it was founded on truth, it made progress of 

 itself, and has now become one of the most important ques- 

 tions which have engaged the geological public. Owing to 

 the great number of works published of late years on this 

 question,* the phenomenon of the Alps has assumed the im- 



* Among these works, we may mention those of MM. Agassiz, Desor, A^ 

 Guyot, J. Forbes, Studcr, A. Escher de la Linth, and Blanchet, relating to the 

 Alps; Leblanc, Renoir, Ilogard, and E. Collomb, on the Vosges; Agassiz 

 Lyell, Buckland, Smith, Maclarcn, in Scclland, England, and Ireland; Al, 



