20 AM'I E NT M I X 1 M. 



The chisel above figured was somewhat bruised at the upper end, as though it 

 had been used. Towards the upper end the corners arc taken oft", apparently for 

 the purpose of being held in one hand, while it was struck by a mallet with the 

 other. It has a rough surface, common to these relies, but is symmetrical in form, 

 with a bevel at the cutting edge on both sides. None of the tools show signs of 

 having been ground to an edge on stone, but are beaten down roughly by hammers. 



Artificial Caverns. — On the Aztec, Ohio, Adventure, and Ridge locations, in 

 addition to the pits which are so common along the range, there arc cavities in the 

 mural faces of trap at various elevations, which are ancient and belong to the old 

 copper works. 



The bluffs are sometimes as high as three hundred feet above the valley. There 

 are also breaks or gaps in the range formed by dislocations of the strata or faults, 

 enlarged by the wearing action of the drift forces. The ends of different beds of 

 trap are thus presented to view, rising on either side of the gorges, with precipitous 

 fronts of different heights. One of the strata, and perhaps more than one, is 

 metalliferous, like the scoriaceous bed worked at Copper Falls and at Phoenix 

 Mines, on Point Keweenaw. At the Adventure the metal bearing stratum is very 

 thick and highly charged with copper, disseminated irregularly through it. The 

 ancients wrought upon it extensively, seeking with assiduity for the rich portions, 

 no matter how difficult of access. Some of their excavations on the side of the 

 bluff are scarcely large enough to shelter a bear. Others are more extensive, 

 formed in all conceivable shapes, extending wherever indications of minerals were 

 apparent. The agents of the Adventure Mine have followed the example of their 

 predecessors, but on a larger scale, pursuing the strings and bunches of copper in 

 all directions, till the) disappear. When the mineral fails, like the ancients they 

 strike off at random, and seldom proceed far without encountering other lumps or 

 si null masses. 



Hitherto the true veins near the copper bearing stratum have not proved profit- 

 able. The ancients, exercising their usual skill, expended very little labor upon 

 them. The) showed in this very considerable knowledge respecting the different 

 systems of veins, and also in regard to those anomalous deposits in which the caves 

 are situated. 



Forest Mine, Evergreen Bluffs. — On the ground known by the name of the Ever- 

 green Bluffs ancient pits have been opened southeasterly of the Minnesota works. 

 Some prominent ones have recently (1855) been cleared out on the "Johnson 

 preemption," which disclosed in a few days several tons of copper. Masses had 

 been partly uncovered in the vein, as at the Central Mine, and thus left. On the 

 Nebraska location and on the Rockland, the old excavations are numerous, and 

 wherever they are reopened valuable lodes are exposed. They are not wanting on 

 the wesl of the river. At the forest Mine the present works were commenced 

 upon the site of earlier and ancient operations. A wooden bowl was found near 

 the bottom of one of them, that had been used for baling. Doubtless many others 

 in the vicinity of the Ontonagon exist that are nol yel discovered. 



