OF THE SOUTH SHORE OF LAKE SUPERIOR. 439 



More recently it has been ascertained that there were large masses of unpro- 

 ductive trap, while formerly a location made on the trap-range was considered 

 good as a matter of course. When the discovery had progressed thus far, the Com- 

 pany was organized, stock issued and sold, and instalments called in, with the 

 utmost confidence that veins existed wherever there was an outburst of trap. 



If a small vein or fissure was seen, with or without metal, it was considered cer- 

 tain that a broad, rich, well-defined vein was near by. But at this day there are 

 many small veins from which very good hand specimens may be procured, that lead 

 to nothing valuable. 



From the rich, productive uplifts of the Ontonagon River, as we proceed west- 

 ward, copper does not seem to be as plentiful or as well concentrated. 



All the works in the Porcupine Mountains are abandoned. Farther west, on the 

 waters of the Presqu'ile and Black Rivers, which are next the Montreal, the 

 mass of the trap-rocks has very much diminished ; the ranges, instead of showing 

 entire crests, appear in detached knobs, in which veins would be less likely to be 

 regular or valuable. Where the range crosses the Montreal into Wisconsin, the 

 uplifts are still short and detached, with feeble signs of epidotic veins. Specimens 

 of red oxide and native copper have been seen near the river, not in place. Follow- 

 ing the range westward, there is a gap where Mingopes (or Balsam) River passes 

 through it in a chasm ; here the rocks have changed from an imperfect amygdaloid to 

 those of a hornblendic cast, containing much silex. Its texture is hard, close, and 

 tough ; its angles are sharp-cut and well-defined, apparently suffering nothing by 

 the action of the elements. From thence you ascend what I call the greenstone 

 portion of the range, where there are mural faces looking every way, forming a 

 confused collection of precipices and gulfs, that compose the highest part of the 

 range in Wisconsin. It is a labyrinth of dark valleys, with perpendicular sides, 

 cliffs, and crests, two and three hundred feet above the adjacent low places. These 

 elevations occupy a space two and four miles wide, and ten miles long. The mineral 

 composition of these cliffs varies from an imperfect amygdaloid trap, with magnesian 

 and chloritic amygdules, to an amygdaloidal greenstone, where the kernels are 

 siliceous and epidotic. All these varieties may be seen in the space of a few rods, 

 which are represented by specimens 67 to 77, and 80 to 84, of my collection. 



On the north of this range, as represented on the map, is a belt of low black and 

 red trap, lying between the greenstone and the conglomerate. It is less elevated 

 than the range just described, by three hundred to five hundred feet, and compara- 

 tively level. Much of the trap is concealed by red clay and drift, but is seen occa- 

 sionally in low ridges running parallel to the coast. On the south of the green- 

 stone are hornblendic and clay slates, which rest against the granitic, syenitic, and 

 quartzose rocks of the interior. Fragments of detached trap, containing native silver 

 and copper, are reported to have been found on the range, but I have seen or heard 

 of no well-defined veins. 



The indications that have attracted most attention from explorers are in the black 

 trap next the conglomerate, particularly at the Second Falls of the Montreal River, 

 the Falls of the East Fork of Bad River, and the Falls of Tyler's Fork. In Cornwall, 

 where veins pass from one rock to another, the miner expects a rich deposit near the 



