_Sacrificial._--The sacrificial mounds are characterized by "their almost invariable occurrence within enclosures; their regular construction in uniform layers of gravel, earth, and sand, disposed alternately in strata conformable to the shape of the mound; and their covering a symmetrical altar of burned clay or stone, on which are deposited numerous relics, in all instances exhibiting traces, more or less abundant, of their having been exposed to the action of fire."[88] Among the most remarkable are those found on the Scioto, at the place called Mound City situated on the western bank. The mounds are enclosed by a simple embankment, between three and four feet high. The area occupied is about thirteen acres, and includes twenty-four mounds. One of these is one hundred and forty feet in length, and the greatest breadth is sixty feet. In this mound occurred four successive altars, a bushel of fragments of spear-heads, over fifty quartz arrow-heads, and copper and other relics. The sacrificial deposits do not disclose a miscellaneous assemblage of relics, for on one altar hundreds of sculptured pipes chiefly occur; on another, pottery, copper ornaments, stone implements; on others, calcined shells, burned bones; and on others, no deposit has been noticed. The sacrificial mounds are found at Marietta and other localities. All the investigations which have been made prove that the altars were not only used for a long period, but also had been repeatedly renewed. _Sepulchral._--The sepulchral mounds are numbered by the thousands. They are simple earth-pyramids, sometimes elliptical or pear-shaped, and vary in height from six to eighty feet. Usually they contain but one skeleton, reduced almost to ashes, but occasionally in its ordinary condition and in a crouching position. By the side of them occur trinkets, and, in a few cases, weapons. These mounds were probably only raised over the body of a chief or some distinguished person. _Temple._--The temple mounds are truncated pyramids, with paths or steps leading to the summit, and sometimes with terraces at different heights. Among the most noted of these is that of Cahokia in Illinois. It is seven hundred feet long at its base, five hundred feet wide, and ninety feet high. Its level summit is several acres in extent. _Symbolical._--The symbolical mounds consist of gigantic bas-reliefs formed on the surface of the ground, representing men, animals, and inanimate objects. In Wisconsin they exist in thousands, and among the devices are man, the lizard, turtle, elk, buffalo, bear, fox, otter, raccoon, frog, bird, fish, cross, crescent, angle, straight-line, war-club, tobacco-pipe, and other familiar implements or weapons.