114 M. Ch. Martins' Ihmarks on M. Durochers Memoir 



to S\V. In the Valais, there are strias nearly in the same 

 direction, such as we again encounter in the valley of Cha- 

 monix, between Prieure and the village of Ouches. Accord- 

 ing to M. Durocher's principles, all these stricc having the 

 same orientation are united, and form a system of erosion, 

 which, commencing in the Oberland, passes above the high 

 chain of the Bernese Alps, crosses the Col de Balme, and ex- 

 tends to the foot of Mont Blanc ; while, in reality, these 

 striae belong to three different glaciers ; that of the Aar, that 

 of the Rhone, and that of the Arve, which had nothing in 

 common with each other, excepting that their directions were 

 parallel at one point of their progress. According to this 

 view of the subject, we should be forced, in order to be con- 

 sistent, to consider the strioe lying in the same direction in 

 the Alps, Vosges, and Pyrenees, as forming part of one sys- 

 tem of erosion, over a space of four degrees of latitude, like 

 that which many of M. Durocher's systems of striee compre- 

 hend \ while the latest evidence goes to prove that these stria? 

 have been engraved by glaciers descending from mountains 

 into valleys, and not by a general agent proceeding from the 

 north to the south, or from the east to the west. 



Faithful to his principle of assuming the direction of the 

 striae as the sole guide in studying the line of route followed 

 by the agent which traced them, an observer, proceeding on 

 this method, would be forced to regard the furrows formed 

 by a principal glacier, and those made by its tributaries, as 

 belonging to different systems. In the valley occupied by 

 the glacier of the Aar,* such a geologist would consider the 

 striae directed from west to east which this glacier has en- 

 graved under our eyes, as forming part of one system, while 

 those of its tributaries, the glaciers of Thierberg, Silberberg, 

 Griinberg, and Zinkenstock, which cut the former at right 

 angles, more or less obtuse, he would regard as belonging to 

 another system. 



The plan followed by M. Durocher appears to me, there- 

 fore, erroneous, whether we apply it to the hypothesis of gla- 



* See the plan of the glacier of the Aq.t, Bulletin de la Society Oeohgique, 2d 

 series, t. iii,, PI. V., fig. 12. Meetiug of 2d March 1846. 



