GEOLOGY OF THE WESTERN ALPS. 169 



earth-movements of the district, which M. Termier says 

 gives a certain support to Bertrand's theory of the recurrence 

 of dislocations on the same lines. Its support, however, 

 is very qualified, for the area supplies several exceptions to 

 the law. It appears, however, that ridges occurred having 

 the same trend as the existing ones in times earlier than 

 any of the fossiliferous rocks of the district. The view 

 that the Alps were modern in their development was once 

 accepted. The Grandes-Rousses, however, supplies only 

 one more to the cases which show that the Alps date back 

 to pre-Carboniferous times. 



The occurrence of intrusive gneisses in the Alps is not 

 quite new, for M. Michel Levy has shown that the central 

 mass of Mont Blanc is not a Laurentian, metamorphic 

 gneiss, but an intrusive granite which acquired a foliation 

 during solidification. This intrusion, however, certainly 

 happened in pre-Carboniferous times. This view has been 

 confirmed by MM. Duparc and Mrazec not only for the 

 main mass of Mont Blanc (10), but also for its northern 

 outlier, the massif of Trient (11). The centre of the latter 

 also consists of a protogine gneiss ; on the flanks of this 

 occur mica-schists and amphibolites which are injected by 

 veins of granulite. The amphibolites offer resistance to 

 the process of injection, so that the granulite is far more 

 abundant in the mica-schists. A plate containing two 

 photographs illustrates very clearly the different types of 

 scenery formed by the two sets of rocks, contrasting the 

 massive irregular crags of the eclogites with the smooth 

 slopes of the mica- schists. 



Another paper (12), published in the Quarterly Journal 

 of the Geological Society, deals with a single peak in the 

 Cottians. It is an effort to establish a stratigraphical 

 sequence in the main chain of the Western Cottians. 

 Monte Chaberton is a fine dolomite mass on the northern 

 side of the historic pass of Mount Genevre. It has been 

 familiar in geological literature since 1861, when, in an 

 excursion of the Societe Geologique de France, some 

 fossils were found in some limestone boulders on the south- 

 eastern slopes. A further collection of these was made by 



