358 



THE AZOIC SYSTEM AND ITS SUBDIVISIONS. 



Hunt for systems which are entirely theoretical, in which category wc may in 

 my opinion include the Norian, Montalban, Taconian and Keeweenian. These, 

 one and all, so far as known, are simply groups of strata which occupy the 

 same geological interval, and present no greater differences in their physical and 

 mineralogical characters than are commonly observed to occur both in forma- 

 tions of the same epoch in widely sepdrated regions, and when physical acci- 

 dents, such as contemporaneous volcanic action or subsequent mctamorphism 

 have locally affected the general character and aspect of the formation withm 



limited areas Unfortunately in Canadian geology, hitherto, stratigraphy 



has been made subordinate to mineralogy and palaeontology, and, as the result, 

 we find groups of strata which the labours of the field geologists durmg the 

 past ten years have now shewn all to occupy a place between Laurentian and 

 Cambrian, assigned to Carboniferous and Upper Silurian in New Brunswick 

 and Nova Scotia, to the peculiar pal^ontological L6vis group and its subdivis- 

 ion Lauzon and Sillery, in the Eastern Townships, and to Lower and Upper 

 Laurentian, Huroniau, Lower Silurian and Triassic on the north .ide of the 

 St Lawrence valley and around Lake Superior. The same system ot mmera- 

 lo-ical stratigraphy is now further complicating and confusing the already 

 quite sufficiently intricate problem by the introduction of the new nomencla- 

 ture I have referred to, and in some cases these nfimes are apphed regardless ot 

 and in direct opposition to well ascertairuHl stratigraphical iacts. A similar 

 unfortunate instance of pala^ontological stratigraphy is found in the histoiy of 

 the Quebec group ; and especially in the late introduction m it of the belt ol 

 supposed Potsdam rocks, about which I have already stated, my opmion In 

 the reconstruction of tlie geological map of Eastern Canada, - and in this I 

 include the country from Lake Winnipeg to Cape Breton and Labrador, ~ ren- 

 dered necessary by the present state of our knowledge, I should propose to 

 adopt the foUowing divisions of systems to include the groups enumerated : — 



*'L Laurentian: . 



''To be confined, to all those clearly lower unconformable granitoid or 

 syenitic gneisses in which we never find interstratified bands of calcareous, 

 argillaceous, arenaceous and conglomeratic rocks. 



''IL Huronian: . 



»To include — 1. The typical or original Huronian of Lake Superior and 

 the conformably — or unconformably, as the case may be-overlyhig upper 



copper bearing rocks. 



« 2. The Hastings, Templeton, Buckingham, Grenville and Kandon crystal- 

 line limestone series, 



*' 3 The supposed Upper Laurentian or Norian. 



"4 The altered Quebec group, as shewn on the map now exhibited, and 

 certain areas not yet defined between Lake Matapedia and Cape Maguereau m 



Gaspe. ^^ . ,. , , 



" The Cape Breton, Nova Scotia and New Brunswick pre-Primordial sub- 

 crystalline and gneissoid groups. 



