64 THE CANADIAN NATURALIST. [Vol. vlli. 



is a horizontal dislocation of 400 feet, being equal to a down- 

 throw of 200 feet. At Portage Lake the faulting amounts to 

 over 700 feet horizontally. The effect of this fault has been to 

 weaken the country, and since denuding agencies have made an 

 excavation across Keweenaw Peninsula, having a depth of six or 

 seven hundred feet through the Range. The lower portion of 

 this valley is now occupied by Portage Lake. 



Bell has suggested that the igneous eruptions occurred within 

 the present basin of Lake Superior. This was probably the case, 

 and what is now the bed of the lake was the scene of action for 

 some gigantic submarine volcanoes, which piled up two and a half 

 or three miles of solid rocks. The axis of the great eruptions 

 appears to have been somewhere between Keweenaw Point and 

 Nipigon Bay, where were the thickest deposits, whence the ma- 

 terial flowed all around, having a radius of 150-200 miles. It 

 Is probable thatthegreat basin of Lake Superior, which is one of 

 aqueous denudation, is due to the great weakening of this regio* 

 by the numerous dykes and f.ults belonging to the Cambrian or 

 Pre-Cambrian Ages, arising from the many channels of eruptions 

 during those Ages; for while the crystalline Laurentian, 

 Huronian, and some of the Nipigon Series of rocks, have with- 

 stood so persistently the denuding agencies of countless /Eons, we 

 find in the centre of them, the largest or one of the largest lake 

 basins on our globe; and that the former scene of the greatest 

 disturbance is now covered by the deeper waters of the lake. 



d. — Geological Age of the Nipigon or Copper- Bearing Series. 

 — The Geological age of these rocks has long been an open ques- 

 tion, as recourse to organic remains cannot be made. Nor is it 

 probable that future researches will unveil many fossils, as the 

 conditions of the seas were totally unfavourable to life. Ateack 

 eruption all organisms would t nd to be destroyed. The red 

 sandstones also indicate, at least, a scarcity of vegetable existence, 

 and then the time elapsing between each period, when the sedi- 

 mentary deposits were forming, were occupied by long successions 

 of volcanic eruptions. However, in one of the sandstone beds, 

 raear the top of the Cupriferous Series, over which the Eagle 

 Kiver flows, and near its mouth, a Mr. Uren found an ob- 

 jure fossil, but as he stated to me, he cared not for palaeontolo- 

 gical remains and consequently gave it to auother gentleman, wh» 

 was not scientific. Dr. Sterry Hunt also mentioned the possi- 



