[TYRRELL] PRE-CAMBRIAN GOLDFIELDS OF CENTRAL CANADA 91 



Algoman (granite-gneiss, batholitic in Huronian) 

 Irruptive contact 



Huronian 



Upper 



Unconformity 

 Lower 



Archaean 



Unconformity 



Laurentian (granite gneiss, batholitic inOntarian) 



Irruptive contact 



Ontarian | Keewatin 



Coutchiching 



^Dr. Coleman's classification is as follows: 

 Keweenawan 



Discordance 

 Animikie 



Discordance 



Post-Laurentian 



Upper Huronian 



Small Discordance 

 Lower Huronian 



Great Discordance 

 Laurentian in eruptive contact with lower rocks.. 



^ A. P. Coleman. The Pre-Cambrian Rocks north of Lake Huron. 23rd Rep. 

 Ont. Bur. Min., 1914, p. 206. 



