iHAKviE] PALAEOZOIC BRECCIA OF THE VICINITY (Jh' MONTREAL 275 



crystals. There are also outlines of other phenocrysts, one of which 

 shows traces of cleavage corresponding to augite. Apatite occurs Both 

 as numerous large crystals and as needles. Pyrite, magnetite (or ilme- 

 nite) and perovskite are present in fair amounts. Numerous vague- 

 bordered laths are strongly suggestive of melilite, but are not positively 

 identifiable. Doubtful hydronephelite is present in the base. 



MONTARVILLE. 



On the west slope of Montarville there is a group of breccia dykes. 

 The largest is about fifteen feet wide, but can only be traced for fifty or 

 seventy-five yards. It is composed almost exclusively of fragments of 

 hornstone. The paste has not been abundant enough to crystallise well, 

 so that a section does not give any clue as to its classification. The one 

 striking feature is the great abundance of pyrrhotite. The other dykes 

 are much smaller and composed chiefly of sandstone fragments, in a 

 matrix of typical camptonite. It seems probable that the large dyke is 

 related to these. 



COERELATION OF THE OCCURRENCES. 



In the detailed description of the various occurrences of breccia, no 

 attempts at comparisons or correlation were made. The petrogi'aphical 

 features of the matrices are clearly seen from the following table or 

 synopsis, in which the characteristic minerals, — perovskite and melilite 

 have been selected as the basis for comparison. 



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