in the Mississippi valley a succession of earthworks, manifestly defensive in character, extending from the lakes southward to the gulf. They generally crown the summits of steep hills, and consist of an embankment and exterior ditch, of varying dimensions, with approaches often artfully covered. Fort Hill, on the banks of the Little Miami river in Ohio, has a line of circumvallation nearly four miles in extent, varying in height, according to the natural strength of the point protected, from 10 to 20 feet, and embracing an area of several hundred acres. When not erected near to streams, and in cases where springs are not included within their lines, we almost always find artificial reservoirs for holding water.
Ancient Works near Chillicothe, Ohio.
A large class of these defensive works consist of a line of ditch and embankment, or of several lines one within another, carried across the necks of peninsulas or bluff headlands formed within the bends of streams. Associated with these defensive works, and often included within them, are structures connected with religious ideas and ceremonies. They consist of earthworks with their ditches, when such exist, interior and not exterior to the walls, of regular outline, squares, circles, octagons, and other geometrical figures, often combined, and sometimes of great extent; as for instance at Newark, Ohio, where they cover an area of more than two miles square, and probably comprise upward of 12 miles of embankment from 2 to 20 feet in height. (See "Monuments of the Mississippi Valley," by Squier and Davis, forming the first volume of the "Smithsonian Contributions to Knowledge.") Other works of a sacred or religious origin, consisting of mounds of earth and stone of various sizes, but always regular shapes, are found in connection with those above described, and are very numerous. They are oftenest square, terraced, and ascended by graded ways; sometimes hexagonal, octagonal, or truncated, and ascended by spiral paths, in most respects coinciding with the teocallis of Mexico and the topes of India—the high altars, symbolical in form, on which the priests offered up sacrifices, and paid adoration to the solar god. Some of these arrest our attention by their geometrical accuracy of form, and others by their great size, covering several acres of ground, and rising to imposing altitudes. A mound of this description, on the plain of Cahokia, Illinois, opposite the city of St. Louis, is 700 feet long by 500 feet broad at the base, and 90 feet high, covering upward of eight acres of ground, and having 20,000,000 cubic feet of contents. These mounds frequently contain skeletons. The most common monuments in the Mississippi valley, however, are those which are incontestably simple places of sepulture, memorials raised over the dead, and in their size probably bearing a certain relation to the importance when living of the personages over whom they were erected. Some of these, like that at Grave Creek near Wheeling in West Virginia, and that at Miamisburg in Ohio, the one 70 and the other 68 feet in vertical height, no doubt mark the graves of personages of high consequence among the builders of these monuments. It sometimes happens that one of these sepulchral mounds contains two or more skeletons, but they rarely cover more than one, except in cases where the later Indian tribes, with a vague notion of their sanctity, have buried their dead in them.
Conical Mound, Marietta, Ohio.
The early white settlers also occasionally buried in them. The notion that
