HURONIAN ROCKS OF LAKE SUPERIOE. 73 



merate material. At Sawyer's Bay, the Animikie strata corresponding to those exposed 

 on the south-west side in the high part of Thunder Cape, appear to me to have been 

 denuded away to a depth of nearly 1,000 feet, or to their present level beneath the 

 Keweenian strata on the east side, instead of having been brought into that position 

 by a dislocation as geologists have generally supposed. 



In conclusion, I would state that it appears to me that the Laurentian gneisses and the 

 Huronian schists of Lake Superior were together involved in a grand disturbance of the 

 rock-formations, which resulted in a general upturning of the strata, and that there had 

 also been a general levelling down of these rocks before the Animikie age. Again it 

 appears that after the deposition of the Animikie formation, geological changes took place 

 withovrt causing much alteration of level, in the course of which the strata were dis- 

 located in many places and afterwards eroded and levelled down to a considerable extent 

 before the commencement of the Keweenian age ; and again, as before stated, that the 

 sinking of the Lake Superior geological basin took place after the building up of the 

 Keweenian group, and before the deposition of the Sault Ste. Marie sandstones. It seems 

 probable, that the sinking of the Lake Superior basin was the only event which separated 

 these two formations. 



Sec. iv, 1887. 10 



