256 Elie tie Beaumont's Researches on some of 



and that of the islands of Corsica and Sardinia, are respectively 

 nearly parallel to those of the system of Westmoreland and the 

 Hundsruck, of the system of the Ballons and the hills of the 

 Bocage, and of the system of the North of England. The cor- 

 responding directions only differ in a few degrees, and the two 

 series have succeeded each other in the same order ; leading to 

 the supposition that there has been a kind of j)efiodical recur- 

 rence of the same, or nearly the same, directions of elevation. 



XI. Sj/stem of the Western Alps. — The opinions in accord- 

 ance with which M. Jurine named the granitic rock constitu- 

 ting Mont Blanc Protogine, can no longer be sustained. The 

 tertiary beds which have been deposited horizontally in that 

 part of the valley of the Rhone which runs N. and S. are 

 constantly contorted and thrown up as they approach the 

 Alps. A similar observation has been made in the valley of 

 the Danube by Professor Sedgwick and Mr. Murchison, who 

 found the cretaceous and tertiary beds to extend horizontally 

 to the foot of the Bohemian mountains, and to be thrown up 

 on entering the Austrian Alps. Messrs. Lyell and Murchi- 

 son have made analogous observations on the tertiary rocks 

 of Lombard)'. Professor Buckland and M. Brongniart have 

 pointed out the tertiary aspect of the fossil shells discovered 

 at the Diablerets, at more than 8000 feet above the level of 

 the sea; shells the relative age of which certainly does not go 

 back beyond the last portion of the cretaceous epoch. 



Although we are generally accustomed to consider the 

 union of those mountains bearing the single name oi the Alps 

 as constituting an undivided whole, we can easily recognise 

 that this vast assemblage is due to the crossing of several 

 systems, independent of each other, and distinct both in age 

 and direction. We should therefore not feel surprise that 

 their structure is more confused than that of a chain thrown 

 up by a single effort, such as the Pyrenees. Throughout nearly 

 their whole extent, and especially on their eastern side, we 

 still perceive traces of numerous small chains of mountains 

 with the same direction as the Pyrenees, and elevated in like 

 manner prior to the deposition of the tertiary I'ocks. The 

 system of Mont \ho is strongly marked in the French Alps. 

 These traces of comparatively ancient dislocations are, how- 

 ever, often marked by disturbances of a more recent date. 



The highest and most complicated portions of the Alps, 

 those near the Mont Blanc, Mont Rose, and the Finsteraar- 

 horn, are principally due to the crossing of two recent systems 

 which meet at an angle of from 45^ to 30°, and which are di- 

 stinguishable from the system of Mont Viso and the Pyreneo- 

 Apennine system, as well by their age as their directions. In 



consequence 



