112 Charpcntier's Essay 07i Glaciers. 



tion. On this point, M. de Charpentier, who has carefully 

 examined the Pyrenees, affirms that erratic blocks are found 

 there, in a great number of places, and in the same circum- 

 stances as among the Alps ; and he assures us, that if he has 

 not given a special description of them in his Essat/ on the 

 Geognostical Constitution oftheFyrenees^ the fact only proves the 

 ignorance in which he then was respecting the cause of the 

 transportation of these debris. Independently of the objec- 

 tions which M. de Charpentier advances against each of the 

 causes alleged as producing these supposed great currents, he 

 thinks that the latter, whatsoever may have been their origin, 

 cannot explain the dispersion of erratic blocks. He refutes 

 by facts the support which this hypothesis was thought to re- 

 ceive from the effects of the debacle of Bagnes. The want 

 of selection, according to the size of the blocks, so remarkable 

 in the erratic formation, where the largest are often carried 

 furthest, — the absence of all traces of the shocks which debris 

 so considerable, projected with a velocity estimated at from 

 175 to 354 feet in a second, should have produced on the side 

 of the Jura facing the valley of the Rhone, — the impossibility 

 of supposing water so charged with debris and mud, as to 

 support the blocks at the surface, since these materials are no 

 longer found, or to understand how they should not have fal- 

 len after issuing from the enclosure of the valleys ; the state of 

 preservation of a great number of them ; the form and situa- 

 tion of the accumulated deposits ; the groups of the same species 

 of rocks ; the fantastically balanced position of many blocks ; — • 

 all these circumstances furnish M. de Charpentier with suffi- 

 cient arguments, in his opinion, to render the idea of the trans- 

 portation of erratic blocks by currents of water inadmissible. 

 He at last comes to the hypothesis brought forward by M. 

 Schimper in a German ode (die Eiszeit), and developed by 

 M. Agassiz, of an inclined plane of ice on which the erratic 

 debris have moved along from the Alps to the Jura. This 

 supposition was explained in detail in the Bibliotheque Univ. 

 de Geneve (Feb. 1841), to which we have already alluded. 

 M. de Charpentier cannot admit it. He observes that the 

 author has not signalized any of the causes which could have 

 produced the excessive sinking of temperature, which he sup- 



