308 THE GEOLOGY OF MONTE CHABERTOJJ. [Aug. 1894. 



We have examined microscopically three specimens, two from the 

 greenstone-schists a little to the north of the summit of Chaberton, 

 and one from the dyke by the bed of a stream north of Gr. Baisses. 

 The former consist mainly of lines of chlorite separated by bands of 

 quartz, with a little authigenous white mica and some fragments of 

 plagioclase ; in one of the specimens there is an enormous amount 

 of secondary quartz. The dyke by the stream consists also of much 

 chlorite and quartz, with patches of a quartz-zoisite-calcite aggre- 

 gate ; there is, moreover, a good deal of titanoferrite passing into 

 leuooxene. These rocks belong to the series which includes the 

 appeninite, besimaudite, ovardite, etc., of some writers on the 

 district. They are doubtless altered basic igneous rocks, probably 

 crushed epidiorites. The only name, however, which we feel 

 justified in attaching to them at present is that of quartz-chlorite 

 schists or greenstone-schists. 



We hope to consider the correlation of these two sets — the older 

 Clavieres serpentine and later chlorite-schists — with the ' pietre 

 verdi' of other localities in the Cottians, in a more detailed account of 

 these rocks and their distribution. But it may be worth mentioning 

 here the probability that there is a third group of basic igneous 

 rocks in the Cottians, which are of still later age. The gabbros, 

 diabases, and porphyrites of Mont Genevre, and of Rocciavre (north 

 of the pass of F enestrelle), may belong to this age ; there is evidence 

 suggesting that the gabbros of the former locality are intrusive 

 through the serpentines at Punta Raseia. 



The Earth-movements of Monte Chaberton. 



No description of this mountain would be complete that omitted 

 reference to the folds, faults, and thrust-planes that have combined 

 to render its geology so complex and interesting. We should have 

 wished to possess a large-scale map, and carefully work out the 

 whole of its numerous faults. But the prolonged involuntary 

 residence in the country that might have resulted from this detailed 

 mapping would have been so inconvenient to both of us that we 

 thought it advisable to forbear. A more precise survey must be 

 left to an Italian geologist, until such a time as the nations of the 

 Continent shall beat their bayonets into hammers ; the numerous 

 forts in the district will then afford superior accommodation to any 

 that can now be got in the inns. 



The movements may be divided into four main sets : 



(1) A thrust-plane that has carried the Trias on to the calc-schists. 



(2) A series of north-and-south faults that has troughed the 

 Cretaceous limestones into the dolomites. 



(3) Some east-and-west faults, to one of which the Col de 

 Chaberton is due. 



(4) A fold that has inverted the calc-schists on the eastern slope, 

 and there caused an infold of the Trias. 



The accompanying map and the section (fig. 3, p. 310) illustrate 

 the general arrangement of these movements, but the exact order of 



