310 



THE GEOLOGY OF MONTE CHABERTON. [Aug. 1 894, 



their succession is doubtful. Numerous minor faults that do not 

 affect the relations of the different beds to one another are omitted. 



Fig. 3. — Section through Monte Chaberton. 



3 



CT77777771 



Clos des Moris Limestones— Cretaceous. 



Dolomites, Tufas, ami Basal Quartzites Trias. 



.... Calc- Schists _ Pre-C arbonifcrotts. 



...Serpentine Pre-Triassic. 



Greenstone -Schists _. Post-Triassic. 



F....Pa/etts. T... .Thrust-Plane. 



In conclusion we may summarize the results of the present paper 

 as follows : — 



(1) In the Cottian Alps there have been three distinct series of 

 intrusions of basic rocks, the first pre-Triassic and post-scJiistes 

 lustres, the second post-Triassic and pre-Cretaceous, the third 

 probably Lower Tertiary or Cretaceous. 



(2) That the ' Calcaire du Brianconnais ' consists of three distinct 

 rocks : — the cargneules and dolomites of the Trias, the limestones of 

 the Jurassic (which contain representatives, according to Kilian, of 

 the lower, middle, and upper divisions of that system), and thirdly 

 the shelly and coralline limestones which we call the Clos des Morts 

 Limestones of the Cretaceous (possibly Turonian). 



(3) That, in spite of the many doubts thrown upon the presence 

 of Cretaceous beds in the Western Alps, representatives of such beds 

 are known in at least two places in the Cottians. 



(4) The identification of the common Gosau coral ( Calamophyllia 

 fenestrates, Reuss) in the Cottians. 



Discussion. 



Prof. Cole congratulated the Authors upon their survey of a diffi- 

 cult mountain-area. To him the most interesting rocks were the 

 schistose dykes near the summit of Monte Chaberton, showing how 

 much metamorphism might have taken place in the ' pietre verdi ' 

 generally since Triassic, and probably since Eocene times. He 

 believed that the metamorphism produced in the Alps by Cainozoic 

 earth-movements equalled anything that had gone on in earlier 

 eras. 



Dr. J. "W. Gregory also spoke. 



Mr. A. M. Davies, in reply, pointed out that the remarkable way 

 in which the variolitic rocks of Mont Genevre had escaped crushing 

 was one of the facts that pointed to their very recent date. 



