Pre-Laurentian 



92 THE ROYAL SOCIETY OF CANADA 



f Sudbury Series. 



I Great Discordance 



(Granite eruptive through the Keewatin). 



Keewatin, probably = Grenville Series. 



^Dr. Miller has proposed the following classification: 



Keweenawan Diabase of Cobalt, Norite of Sudbury, and Sand- 

 stones, conglomerates and marls of Thunder 

 Bay, etc. 



Animikean Quartzite, Conglomerate, etc., of Cobalt, etc., 



Slate, conglomerate, etc., of Hudson Bay, etc. 



Algoman Intrusive granite. 



Temiskamian Conglomerate, quartzite, slate, etc., often schistose 



and usually dipping at a high angle. 



Laurentian Granite and gneiss. 



Loganian Crystalline limestone and Iron Formations (sedi- 

 mentary). 

 Keewatin complex (igneous). 



But the latest classification, and the one which includes work done 

 in 1914 in the district in which Sir William Logan first proposed the 

 "Division of the Azoic rocks of Canada into Huronian and Laurentian" 

 is that of W. H. Collins.^ 



1 W. G. Miller and C. W. Knight. The Pre-Cambrian Geology of Southeastern 

 Ontario, 22nd Rep. Ont. Bur. Min. Pt. II, 1914, p. 126. 



^W. H. Collins. The Huronian Formation of Timiskaming Region, Canada. 

 Museum Bull. 8. Geol. Sur. Can., Dec. 28, 1914. 



