Reports and Proceedings. 225 



but that a seam or mass of the Cannel, which here contains 

 numerous scarcely rounded grains of quartz, was passed through in 

 the midst of a series of layers of black, partly unctuous clay, which 

 also contained many similar quartz -grains ; these grains gave to the 

 clay a poirphyritic aspect, so that by sight alone one might be led to 

 consider them a decomposed porphyry. The chief conclusions at 

 which the author arrived were, (1) that, with the exception of the 

 Stoney Creek Cannel, all the oil-producing deposits occur in the 

 Upper Coal-measures, and that the Cannel of Stoney Creek, on the 

 Eiver Hunter, occurs in the Lower Coal-measures, which are above 

 the Lower Marine Beds with Trilobites, below which again are 

 numerous fossiliferous beds before the porph"yry is reached ; and (2) 

 that the Cannel belongs to beds in which Glossopteris occurs, and 

 therefore may be a slight additional evidence of their antiquity, as 

 it is an analogue of the " Bog Head " Cannel of Scotland. 



3. "Eemarks on the Copper Mines of the State of Michigan." 

 By H. Bauerman, Esq., F.Gr.S. 



The author described briefly the different conditions under which 

 native copper is found in the trappean belt of the Upper Peninsula 

 of Michigan, on Lake Superior. The district in question is a narrow 

 strip of ground about 14:0 miles long, and from two to six miles in 

 breadth, made up of alternations of compact and vesicular traps, 

 with subordinate beds of columnar and crystalline greenstones, con- 

 formably interbedded with sandstones and conglomerates. Three 

 different classes of deposits are known, namely, transverse or fif.sure 

 lodes hx the northern district, cupriferous amygdaloids and conglo- 

 merates following the strike in the central or Portage district, and 

 irregular concretionary lodes also parallel to the bedding, in the 

 southern or Ontonogon district. In the fissure- veins copper occurs 

 either spotted through the vein-stuff, or concentrated in compara- 

 tively smooth plates, or lenticular masses, of all sizes up to 500 

 tons. Li the Ontonogon lodes the masses are also large, but of 

 much more irregular forms. In the Portage district, on the other 

 hand, only small masses are found, the great production of the 

 mines of this region being derived from the finely divided spots and 

 graias interspersed through the amygdaloids and conglomerates. 



After giving details of the phenomena observed ia the lodes of 

 particular mines, and a list of the principal alternations of minerals, 

 chiefly zeohtes with quartz, native copper, and calcite, the latter 

 mineral being both newer and older than the- copper, the author 

 proceeded to notice the various hjrpotheses that may be framed for 

 elucidating the occurrence of native copper in the Lake Superior 

 traps. Two principal sources were indicated, the first on the sup- 

 position that protoxide of copper may have originally formed part of 

 the felspathic component of the trap, or that the same rock may 

 have contaiued sulphuretted compoimds of copper mechanically in- 

 termixed; while, according to the second view, the overlying sand- 

 stones may have contained small quantities of copper-bearing 

 minerals in a similar manner to the Kupferschiefer and other Per- 

 mian and Triassic rocks in Europe. Supposing the trappean rocks 

 VOL. III. — NO. xxni. 15 



