in the Erratic Basin of the Bhone. 265 



the basin. Along with these the Yalorsine region of blocks 

 commences. Beyond Romont and the valley of La Glane, 

 on the heights which separate this valley from that of La 

 Bi'oye, some whitish granites of the Haiit Valais mingle with 

 the pudding-stones of Yalorsine ; we then see the euphotide 

 blocks of Saas, accompanied with the talcose chlorites and 

 serpentines of Mont Rosa. In the space comprised between 

 Broye and the banks of the lake of the Neuchatel, the arke- 

 sines and chloriteous gneiss are joined to the preceding 

 rocks. On the north bank, beyond the lake, the latter and 

 the chlorites become predominating ; the Valorsine rocks 

 have almost disappeared. On ascending the sides of the 

 Jura, from five or six hundred to a thousand feet above the 

 lake, and not till then, the granites of Mont Blanc make their 

 appearance. It is the inferior zone of large blocks. 



Lastly, above a space of nearly a thousand feet in height, 

 in which almost all the Alpine rocks disappear, the superior 

 zone of the large blocks of Mont Blanc, with which the 

 Pennine rocks are intermixed, forms the most elevated limit 

 of the erratic formation. 



"NVe must therefore distinguish three principal regions in 

 this section ; that of the Valorsine pudding-stones along the 

 Alps ; that of the blocks of Mont Blanc along the Jui'a ; and 

 those of the Pennine rocks, preceded by some granites of the 

 Haut Valais and rocks of Mont Rosa, in the centre. 



The section across the western part gives us an analogous 

 series. 



The heights of Chablais, in the neighbourhood of the 

 outlet of the Dranses, shew us the granites of Mont Blanc, 

 less numerous, however, than might be expected in the upper 

 part ; and allied to the chlorites which rise almost to the same 

 level. Further down, the arkesines and chloriteous gneiss 

 form a junction with them, on the sloi')es which overlook 

 Thonon, Evian, and La Tour Ronde ; but the euphotides and 

 serpentines are still rare. Beyond Leman, to the south of 

 Aubonne, and near Nyon, the rocks of Mont Rosa are very 

 abundant. Lastly, at a greater distance, towards the Jura, 

 we meet with the wliite granites of Ilaut Valais, the pudding- 

 stones of Valorsine, and granites of Mont Blauc, niingled with 

 the preceding rocks, but predominating. 



