1846.] Copper Mines. 63 



In consequence of the absence of fossils in the sandstone and 

 its concealment at, or near, the places of junction with succeed- 

 ing rocks, its age yet remains undetermined. It would seem, 

 however, to be analagous to the Potsdam sandstone of the New 

 York series, and this opinion Mr. Lyell is inclined to adopt. It 

 rests upon the primary, for it is not customary to separate it from 

 the conglomerate beneath. Capt. Bayfield's views of its place 

 and age are quite indistinct, and the only definite opinion which 

 he expresses is, that it is older than the old red sandstone — the 

 rock which constitutes so large a part of the Catskill mountains. 

 It is, however, below the Lake Huron limestone, a limestone 

 which is in fact equivalent to the Niagara limestone in the New 

 York system. This would of course make it much older than the 

 old red sandstone, and would either make it equivalent to the Me- 

 dina or the Potsdam sandstone. Our opinion is, that it is the 

 latter, disguised in various ways by its heterogeneous composition 

 and the intense igneous action to which it has been subjected. 

 The Potsdam sandstone, near the falls of Montmorenci, is parti- 

 colored and stained with copper, and at many places it is a brown 

 or red color, and contains iron — in other places, it is white, gray, 

 brown, striped, and sometimes iron-black with quartz seams, and 

 somewhat resembling graywacke, except that its color is much 

 darker. 



Having stated very generally and briefly some of the facts 

 which relate to the rocks of Lake Superior, we now propose to 

 speak of them as mineral depositories, after which, we intend to 

 follow Capt. Bayfield back through the northwest region, that we 

 may lay before our readers the principal facts connected with the 

 junction of the sedimentary with the primary rocks, from this 

 lake to the Gaspe district upon the Gulf of St. Lawrence. 



Locations of the JYew York and Lake Superior Mining Company. 



This company has leased sixty-five square miles of the mineral 

 lands in eight tracts, of which two are situated near Dead river, 

 three at Keweena point, and three upon the Great Montreal river. 



