On landing at Eagle river, one of the points for shipping the copper ores, on the west side of the Keweenaw Peninsula, the track lies through dense forest, over a road in some parts of rough corduroy, and in others traversing the irregular exposed surface of the copper-bearing trap. After a time it winds through a gorge, covered with immense masses of trap and crumbling débris, amid which pine, and the black oak and other hard wood, have contrived to find a sufficient soil for taking root and attaining their full proportions; and beyond the cliffs, in a level bottom on the other side of the trap ridge, is the Cliff Mine settlement, one of the most important of all the mining works in operation in this region. Here I descended a perpendicular shaft by means of ladders, to a depth of sixty fathoms, and explored various of the levels: passing in some cases literally through tunnels made in the solid copper. The very abundance of the metal proves indeed, at times, an impediment to its profitable working, owing to the labour necessarily expended in chiselling out masses from the solid lump, to admit of their being taken to the surface, and transported through such tracts as have been described, to the Lake shore. The floor of the level was strewed with copper shavings: for the extreme ductility of the native copper precludes the application of other force than manual labour for separating it from the parent mass. I saw also beautiful specimens of silver, in a matrix of crystalline quartz, obtained from this mine; and the copper of the district is stated to contain on an average about 3·10 per cent. of silver. This is indeed by far the richest mineral locality that has yet been wrought. In a single year upwards of sixteen hundred tons of copper have been procured from the Cliff Mine, and one mass was estimated to weigh eighty tons. Its mineral wealth was known to the ancient miners; but the skill and appliances of the modern miner give him access to veins entirely beyond the reach of the primitive metallurgist, who knew of no harder material for his tools than the native rock and the ductile metal he was in search of.