CANADA. 357 



marvellous instances on Tecord oi ' selective metamorphism.^ But whether this 

 is so or not, there seem to be no good grounds for assigning either an age or an 

 origin to the cupriferous diorites, dolerites, and amygdaloids of the Eastern 

 Townships different fi'om that of the almost identical rocks of Lake Superior," 



Of the Hastings series he says : — 



" The gradual progress of the work, however, from west to east has now, I 

 think, conclusively demonstrated that the Hastings group, together with the 

 somewhat more crystalline limestone and gneiss groups, .... furm one great 

 conformable series, and that this series rests c^uite vmcouformably on a massive 

 granitoid gneiss." 



Of the Norian rocks he said : — 



" In not one of the several areas where they are known to occur in Canada, 

 have they yet been mappetl in detail, and even their limits, as indicated on the 



geological map, are more or less conjectural Professor Hitchcock shews 



that they rest unconformably on the upturned edges of the ' Montalhan ' gneisses, 

 leading to the conclusion that the gneisses of the White Mountains are older 

 than the ' Norian,' whereas Dr. Hunt, solely, I believe, on mineralogical con- 

 siderations, supposes these same ' Montalhan ' gneisses to constitute a system 

 newer than the Huronian. Here, then, as in the Hastings region, we find 



theory and experience at variance If it is admitted — which, in view 



of the usual associations of Labrador feldspars, is the most probable supposi- 

 tion — that these anorthosite rocks represent the volcanic and intrusive rocks 

 of the Laurentian period, then also their often massive and irregular, and 

 sometimes bedded character, and their occasionally interrupting and cutting 

 off some of the limestone bands, as descrilied by Sir W. E. Logan, is readily 

 understood by one who has studied the stratigraphical relations of contempo- 

 raneous volcanic and sedimentary strata, of palaeozoic, mesozoic, tertiary and 

 recent periods. Chemical and microscopical investigation both seem to point 

 very closely to this as the true explanation of their origin. That they are 

 eruptive rocks is held by nearly all geologists who have carefully studied 



their stratigraphical relations When we recall the names of Dahl, 



Kerulf and Torrell in Norway, Maculloch and Geike in Scotland, Emmons, 

 Kerr, Hitchcock, Arnold Hague, and others in America, all of whom consider 

 these norites as of eruptive origin, we may well pause before accepting Dr. 

 Hunt's conclusions respecting them, and that they should often appear as 

 * bedded metamorphic rocks,' .... is quite as probable as that we should 

 find the mineralogicaUy similar dolerites occuring in dykes and bosses, and in 

 vast beds interstratified with ordinary sedimentary deposits of clay, sand, etc., 

 as we do over wide areas in Australia and elsewhere. In conclusion, I may 

 say that I fail to see that any useful purpose is accomplished, in the present 

 stage of our knowledge of the stratigraphical relations of the great groups of 

 rocks which underlie the lowest known Silurian or Cambrian formations, by 

 the introduction of a number of new names such as those proposed by Dr. 



