1868.] MACFARLANE— GEOLOGY OF LAKE SUPERIOR. 253 



It is about six feet thick, and is followed by thirty feet of the thin 

 bedded sandstones, some parts of which might yield good flag- 

 stones. Some of the surfaces of these are very distinctly ripple- 

 marked. Above these come thin, shaly, rapidly disintegrating 

 layers, in which are found spheroidal concretions from five to ten 

 inches in diameter. It is not possible to ascertain the total 

 thickness of these sandstones, since they descend beneath the level 

 of the lake. They are similar in lithological character to the 

 sandstones which occur on the north side of Point-aux-Mines. 

 Although there is no doubt that these sandstones unconformably 

 overlie the melaphyre series, still their lithological characters are 

 very different from those of the horizontal red sandstone above 

 referred to. The latter is evenly small-grained, is coloured red by 

 iron oxide, and contains here and there small pieces of red shale, 

 which have evidently furnished the colouring matter, It 

 frequently consists of evenly bedded red and yellowish-grey 

 layers, and exhibits sometimes the phenomenon named by 

 Naumann, discordant parallel-structure, and by Lyell, diagonal or 

 cross stratification. 



In enquiring next as to what geological formation in Europe 

 most closely resembles the Upper Copper-bearing series of Lake 

 Superior, the opinion expressed by Delesse ought not to be lost 

 sight of, viz., that the constituent minerals have- the same meaning 

 and importance for eruptive rocks which organic remains have 

 for those of sedimentary origin. Therefore, where the pakeonto- 

 logical evidence does not entirely contradict it, that derived from 

 lithological resemblance ought to be allowed its full weight. The 

 melaphyres of the upper rocks being interbedded with conglomer- 

 ates and sandstones, the age of the latter may be ascertained 

 approximatively by enquiring under what circumstances and 

 during what period the melaphyres of Europe were developed. 

 Upon this point Naumann thus expresses himself : " With regard 

 " to the eruption-epochs of the melaphyres, there appears, indeed, 

 " to have been many of them, but the most occur in the period 

 " of the Rothliegende, or in the first half of the Permian forma- 

 " tion, and all are probably more recent than the Carboniferous 

 " system This applies at least to the melaphyres on the south 

 " side of the Hundsriick, to those of the Thuringian Forest, of the 

 " neighbourhood of the Hartz, of Lower Silesia, Bohemia, and 

 " Saxony. Many of these melaphyres were deposited soon 

 " after the commencement, others towards the end, of the 



