38 



Archaean 



(No equivalent) 



Eparchacan Interval — Unconformity between the Middle and 

 Upper Huronian. 



Algoman (granites intrusive into the 

 Lower and Middle Huronian). 

 Irruptive contact. 

 Seine series (Middle Huronian). 

 Unconformity. 



Steeprock series (Lower Huronian). 

 Unconformity . 



Laurentian (Laurentian). 

 Irruptive contact. 



Ontario Keewatin (Keewatin). 



(Keewatin) Coutchiching (No equiva- 

 lent?). 



A short quotation (6) will explain Dr. Lawson's method of 

 subdividing the series below the Cambrian: "Upon the 

 vast peneplain resulting from degradation during the 

 Eparchaean Interval were deposited the Animikie sedi- 

 ments. The Animikie is thus separated from the 

 Huronian by an enormous interval of geological time. 

 On the far side of that interval the earth's crust was affected 

 by plutonic activities, involving the Coutchiching, Keewatin 

 and Huronian similarly, which have not recurred in the 

 region so far as is known on the near side of that interval. 

 In other words, the Huronian is allied in its geological his- 

 tory with the Coutchiching and Keewatin, and is part of 

 the Archaean, while the Animikie (Algonkian) is allied with 

 the Palaeozoic." 



In order to complete the geological sequence exposed 

 along the Canadian Northern railway, there should be 

 mentioned an outcrop of Richmond fossiliferous lime- 

 stone (Ordovician) , found by Dr. Lawson, about six 

 miles (9-6 km.) west of Fort Frances, and believed by 

 him to represent an outlier of the Palaeozoic rocks more 

 abundantly exposed in the valley of the Red river in 

 Manitoba . 



