574 Correspondence — Prof. C. Beicalque. 



terra, or of a folding in a solid condition or any other form of 

 dynamo-iiietamorphisra, and he maintains his original opinion that 

 the serpentine {i.e. the original peridotite) is intrusive in the other 

 rocks. 



The paper also deals with some minor points in the geology of 

 the Lizard ; the author supplying some additional particulars about 

 the serpentine at Porthkerris and Porthallow, and explaining that 

 he has found the rocks on the south side of Porthoustock Cove to 

 be only a continuation of those which form the crags south of the 

 opening of the Cove, though they are generally less well preserved : 

 namely, a fine-grained gabbro, intrusive in the ordinary Crousa 

 Down gabbro, and "greenstone " dykes cutting both of these. 



2. "The 'Schistes Lustres' of Mont Jovet (Savoy)." By J. W. 

 Gregory, D.Sc, F.G.S. 



The author gives a history of the controversy as to the age of the 

 '■ schistes lustres ' of the Western Alps, making special reference to 

 the views of Zaccagna and Bertrand concerning the schists of Mont 

 Jovet. Of these writers, the former maintains that the rooks of the 

 summit of the mountain are old rocks on which the Carboniferous 

 and Triassic strata M'ere deposited unconformably ; while, according 

 to the latter author, the rocks forming the top of the mountain were 

 laid down after those which flank it. 



In the present paper the author gives the results of an examina- 

 tion of the rocks of Mont Jovet recently made by him. He contends 

 that Lory and Zaccagna were correct in identifying the central rocks 

 of Mont Jovet as ' schistes lustres,' for this conclusion is supported 

 by their lithological characters and the occurrence of basic igneous 

 rocks of the ' pietre-verdi ' type associated with them, and is not 

 opposed to their stratigraphical relations. It is further maintained, 

 as the result of the evidence collect:ed by the author, that the schists 

 in question are older than the Trias ; for fragments of the schists 

 occur in the Trias, there is a discordance of strike between the two 

 series, masses of dolomite rest unconformably upon the flanks of the 

 schists, and the Trias has escaped nietamorphism which the schists 

 have undergone. The probabilities are in favour of the schists 

 occupying the same relation to the Carboniferous as they do to the 

 Trias ; while the close approximation of the schists to the former 

 shows that the schists are not the altered representatives of the 

 neighbouring Carboniferous beds, and it is therefore concluded that 

 the ' schistes lustres ' are pre-Carboniferous, but evidence by which 

 finally to assign them to any exact horizon before this date is still 

 wanting:. 



COiaS-IESIE'OIsrXDIEI^rOiE- 



ON THE USE OF THE TERM BOLBERIEN. 

 Sir, — Will you allow me a few words on the term Bolderien as 

 applied in the abstract of the interesting paper of Mr. G. F. Dollfus 

 (Geol. Mag., October 1895, p. 474.) on the seas during Upper 



