The only metals found in the mounds are copper and silver, the latter only in very small quantities. A few gold trinkets have been reported, but the evidence is not conclusive that such were deposited by the Mound-builders. Iron ore and galena occur, but no iron or lead.
Copper is found in native masses, and also hammered into implements and ornaments. There is no evidence that this metal was ever obtained from ore by smelting; it was all doubtless worked cold from native masses by hammering. Concerning the locality where it was procured, there is little or no uncertainty. The abundant deposits of native copper about Lake Superior naturally suggest that region as the source of the copper supply; the discovery of anciently worked mines strengthens the supposition; and the finding among the mounds of copper mixed with silver in a manner only found at Lake Superior, makes the matter a certainty. The modern tribes also obtained some copper from the same localities. The Mound-builders were ignorant of the arts of casting, welding, and alloying. They had no means of hardening their copper tools, being in this respect less advanced than the Nahuas and Mayas. In fact copper implements are much more rare than ornaments of the same metal. The implements include axes, hatchets, adzes, knives, spear-heads, chisels, drills, etc. Ornaments are in the form of rings, gorgets, medals, bracelets, and beads, with a large variety of small articles of unknown use, some of them probably used as money. Very small models of larger implements like axes are often found, and were doubtless worn as ornaments.
Silver is of much rarer occurrence than copper, was obtained probably from the same region, and is almost invariably found in the form of sheets hammered out very thin and closely wrapped about small ornaments of copper or shell. So nicely is the wrapping done that it often resembles plating. The gold whose discovery has been reported has been in the form of beads and so-called coins. Mr Dickeson speaks confidently of gold, silver, copper, and galena money left by the Mound-builders. There is no evidence that the use of iron was known, except the extreme difficulty of clearing forests and carving stone with implements of stone and soft copper.
ABORIGINAL POTTERY.
Earthen Vases from the Mounds.
Specimens of aboriginal pottery are very abundant, although much less so within the mounds than elsewhere near the surface. Mr Squier says, "various though not abundant specimens of their skill have been recorded, which in elegance of model, delicacy, and finish, as also in fineness of material, come fully up to the best Peruvian specimens, to which they bear, in many respects, a close resemblance. They far exceed anything of which the existing tribes of Indians are known to have been capable." The specimens in the mound-deposits are, with very few exceptions, broken. The material is usually a pure clay, sometimes with a slight admixture of pulverized quartz or colored flakes of mica, but such admixtures are much rarer than in modern specimens. Notwithstanding their great regularity of form and beauty of finish, none bear signs that the potter's wheel was used in their construction, and no vessels are glazed by vitrification. They are decorated with various graceful figures, including those of living animals, cut in with sharp instruments. A few crucibles, capable of withstanding intense heat, have been found, also terra-cotta images of animals and men, and ornaments or coins in small quantities. Pottery-kilns are found in the south, but that they were the work of the Mound-builders has not been satisfactorily proven. Specimens of the finer class of vases are shown in the cut. The first is of pure clay with a slight silicious mixture. It is five and a half inches high and six and a half in diameter, not over one sixth of an inch in uniform thickness, pierced with four holes in the line round the rim, dark brown or umber in color, and highly polished. The decorative lines are cut in with a sharp instrument which left no ragged edges. The second vase is of somewhat smaller size and coarser material; but more elaborately ornamented and only one eighth of an inch in thickness.
STONE IMPLEMENTS.
Stone implements are more abundant than those of any other material in the altar-mounds and elsewhere. They include arrow and spear heads, knives, axes, hatchets, chisels, and other variously formed cutting instruments, with hammers and pestles. These are made of quartz and other hard varieties of stone, all belonging to the mound region except the obsidian. There is no doubt that obsidian implements were used by the Mound-builders, and as this material is said not to be found nearer than Mexico and California, it is perhaps as likely that the implements were obtained by trade as that they were manufactured in the country. Neither the obsidian knives, nor other stone weapons, show any marked differences from those found in Mexico, Central America, and most other parts of the world. Lance and arrow heads, finished and in the rough, entire or more frequently broken by the action of fire, are taken by hundreds and thousands from the altar-mounds; several bushels of lance-heads of milky quartz were found in one mound. It is a remarkable fact, however, that no weapons whatever are found in burial mounds. Beads, rings, and other ornaments of stone are often found, with a variety of anomalous articles whose use is more or less imperfectly understood. Besides weapons and knives, pipes are the articles most abundant, and on which the Mound-builders expended most lavishly their skill, carving the bowls into a great variety of beautiful forms, at what must have been an immense outlay of labor. A remarkable peculiarity of their pipe-carvings is that accurate representations are given of different natural objects instead of the rude caricatures and monstrosities in which savage art usually delights. Nearly every beast, bird, and reptile indigenous to the country is truthfully represented, together with some creatures now only found in tropical climates, such as the lamantin and toucan. The pipes generally consist of a bowl rising from the centre of the convex side of a curved base, one end of which serves as a handle and the other is pierced for a stem. They are always cut from a single piece, the material being generally a hard porphyry, oftenest red, and strongly resembling in some cases the red pipe-stone of the Coteau des Prairies. The locality where this pipe material was obtained is unknown. Many of the sculptured figures show skillful workmanship and a high polish; I think that many of them are not inferior to the products of Nahua and Maya skill. Some rude stone images of unknown use have been found at various points, but I am not aware that any relics have been authentically reported from the altar-mounds which indicate that the ancient people were worshipers of idols. Mica is the mineral most common in both altar and burial mounds, where it occurs in plates cut into a great variety of forms. Some of them have been conjectured to have served as mirrors. Bushels are sometimes deposited in a single mound. Pieces of coal artificially formed are included by Dickeson among his aboriginal coins.