CHAPTER IV. 



PALEOZOIC ROCK SERIES. 



Beneath the drift the peninsula is underlaid by regularly strati- 

 fled rock beds, in undisturbed horizontal position, which represent 

 the upper part of the palaeozoic strata. 



Of deposits younger than the coal measures, no evidence can be 

 discovered on its surface. It forms the centre-point of an oceanic 

 bay, which seems to have existed, without any important altera- 

 tion in its limits, from the beginning of the Silurian period to the 

 end of the Carboniferous time. We find within the space sup- 

 posed to have been the bay an uninterrupted series of marine 

 deposits, following each other in the greatest regularity of super- 

 position, which represent all the known formations deposited on 

 this continent from the Potsdam period on to the Coal formation. 

 The northern shore of this ancient silurian bay coincided in part 

 with the present north and west shore of Lake Superior. Some 

 cliffs of the present lake, formed by upheaved Huronian rock beds, 

 were formerly the cliffs washed by the breakers of the silurian 

 ocean. 



We find the rounded, water-washed cliffs, with all their fissures 

 and eroded pot-holes, intimately embraced by the sandstones and 

 conglomerates of the Potsdam period, horizontally abutting 

 against them, with their layers discordantly laminated, as we see 

 the sand masses of a beach formed under our eyes. It needs no 

 great degree of illusion to imagine that you see these sand masses 

 dashed upon the shore by the breakers of the present lake, and 

 quickly hardened into rock. One feels strangely impressed at 

 beholding a landscape with its general features as they must have 

 existed myriads of years before, a space of time during which con- 

 tinents formed and disappeared, during which the place itself has 

 undergone the greatest changes, become covered with sediments, 

 the ocean having receded long ages ago from the spot, and then to 



