268 M. A. Guyot on (he Distribution of Bocks 



its euphotldes and serpentines, among which a few Pennine 

 rocks are already mingled. 4M, The moraine of the Pen- 

 nine Alps as far as the foot of the Jura, bth, The left late- 

 ral moraine, formed by the granites of Mont Blanc, which 

 have united themselves, by way of Martigny and tlie Valley 

 of Salvan, to the other rocks of the basin. 



This last moraine is of much greater length than the right 

 lateral moraine. This circumstance, as well as the general 

 inflexion of the interior or superficial moraines, is the ne- 

 cessai'y consequence of the movement imparted to the ice by 

 the configuration of the bed in which it moves ; we have seen 

 it above. 



The line which leaves the foot of the Alps of Guggisberg, 

 forms the limits of the basin of the Rhone, at its contact with 

 that of the Aar, and extends even beyond Aarwangen, is not, 

 in spite of appearances, the continuation of the right lateral 

 moraine, but rather the frontal, which, at first sight, one 

 would have been disposed to seek on the opposite side, on 

 the Jura itself. It is not that we find here, any more than 

 elsewhere, an accumulation which reminds us of the frontal 

 moraines of many existing glaciers; but it is on this line 

 that all the moraines we have named have rested a-breast. 

 Instead of finding only the rocks of the right side on this 

 boundary, as would be the case if it were only a prolonga- 

 tion of the lateral moraine, we find, in passing along it, the 

 rocks of all the rest, and in the order indicated : the Valor- 

 sines at Guggisberg ; the granites of Haut Valais, between 

 Sclnvarzenbourg and Koniz ; the euphotides and serpentines 

 in the neighbourhood of Berne and Bourgdorf ; the arkesines 

 and their companions, at Seeberg and Steinhof ; the granites 

 of Mont Blanc near Arwangen. 



At a posterior epoch, the flow of ice took place nearly 

 in a south-west direction by the basin of the lake of Geneva, 

 and the same phenomena are here repeated. Here, as in 

 the eastern part, the blocks of Mont Blanc, coming down by 

 Salvan and Martigny, form the left lateral moraine. In 

 the Valais and in Chablais, the chlorites mingle with them, 

 soon become predominant, and form the limit at the bottom 

 of the VoironSj on the northern declivity of the Saleve, and 



