Ohio Mounds: Marietta Ohio Mound and Earthwork Complex

Ancient Earthworks at Marietta, Ohio

 A remarkable group of works was among the earliest noticed by Western explorers. It was described by Harte as early as 1791; and a further account was presented in "Harris's Tour," published in 1805, in which an imperfect birds-eye view was also given. Since that period various descriptions have appeared in print; and a number of plans, differing materially in their details, have been published. It is of so much importance, however, and has been the basis of so much speculation, that it is time anaccurate map and a careful description should be placed before the public. Such a map and such a description it is here aimed to present.
      The works occupy the high, sandy plain, at the junction of the Muskingum and Ohio rivers. This plain is from eighty to one hundred feet above the bed of the river, and from forty to sixty above the bottom lands of the Muskingum. Its outlines are shown on the map. It is about three fourths of a mile long, by half a mile in width; is bounded on the side next the hills by ravines, formed by streams, and terminates on the side next the river in an abrupt bank, resting upon the recent alluvions. The topography of the plain and adjacent country is minutely represented on this map.

     The works consist of two irregular squares, (one containing forty acres area, the other about twenty acres,) in connection with a graded or covered way and sundry mounds and truncated pyramids, the relative positions of which are shown in the plan. The town of Marietta is laid out over them; and, in the progress of improvement, the walls have been considerably reduced and otherwise much obliterated; yet the outlines of the entire works may still be traced. The walls of the principal square, where they remain undisturbed, are now between five and six feet high by twenty or thirty feet base; those of the smaller enclosure are somewhat less. The entrances or gateways at the sides of the latter are each covered by a small mound placed interior to the embankment; at the corners the gateways are in line with it. The larger work is destitute of this feature, unless we class as such an interior crescent wall covering the entrance at its southern angle.
The city library sits atop the smaller platform mound

Within the larger enclosure are four elevated squares or truncated pyramids of earth, which, fromtheir resemblance to similar erections in Mexico and Central America, merit a particular notice. Three of these have graded passages or avenues of ascent to their tops. The principal one is marked A in the plan, and an engraving more clearly illustrating its features is herewith presented, Fig. 17. It is one hundred and eighty-eight feet long by one hundred and thirty-two wide, and ten high. Midway upon each of its sides are graded ascents, rendering easy the passage to its top. These grades are twenty-five feet wide and sixty feet long. The next in size is marked B in the plan, and is one hundred and fifty feet long by one hundred and twenty wide, and eight feet high. It has three graded passages to its top, viz. upon the north, west, and east. Those at the sides are placed somewhat to the north of the centre of the elevation. Upon the south side there is a recess or hollow way, instead of a glacis, fifty feet long by twenty wide. This elevation is placed upon an easy swell or ridge of land, and occupies the most conspicuous position within the enclosure, every part of which is commanded from its summit. A few feet distant from the northern glacis, is a small conical mound, surrounded with shallow excavations, from which the earth for its construction, and, perhaps, for the construction in part of the pyramidal structure, was taken. To the right of the elevation, and near the eastern angle of the enclosure, is a smaller elevation one hundred and twenty feet long, fifty broad, and six feet high. It had graded ascents at its ends, similar in all respects to those just described. It is now much obliterated. Near the northern angle of the work is another elevation, not distinctly marked. The two larger squares are covered with a close turf, and still preserve their symmetry. Indeed, no erections of earth alone could surpass them in regularity. They are perfectly level on the top, except where some uprooted tree has displaced the earth.
     There is a passage or gateway one hundred and fifty feet wide, in the middle of the left wall of this enclosure, on the side next the Muskingum. Leading from it towards the river, and at right angles to the embankment, is the "Sacra Via," a graded or covered way of singular construction. It is six hundred and eighty feet long by one hundred and fifty wide between the banks, and consists of an excavated passage descending regularly from the plain, upon which the works just described are situated, to the alluvions of the river. The earth, in part at least, is thrown outward upon either side, forming embankments from eight to ten feet in height. The centre of the excavated way is slightly raised and rounded, after the manner of the paved streets of modern cities, The cross section g h exhibits this feature. This section is constructed from measurements taken at a point midway between the top and base of the grade. Measured between the summits of the banks, the width of the way is two hundred and thirty feet. At the base of the grade, the walls upon the interior are twenty feet high. From this point there is a slight descent, for the distance of several hundred feet, to the bank of the river, which is here thirty-five or forty feet in height. It has been conjectured by some, that the river flowed immediately at the foot of this way at the time of its construction. This is, however, mere conjecture, unsupported by evidence. If admitted, it would give to this monument an antiquity greatly superior to that of the pyramids, unless the deepening of our river channels has been infinitely more rapid in times past, than at present. But one fact favors the conjecture, and that is the entire absence of remains of antiquity upon the beautiful terraces to which this graded passage leads. They may nevertheless have been once as thickly populated as they now are; and this passage may have been the grand avenue leading to the sacred plain above, through which assemblies and processions passed, in the solemn observances of a mysterious worship.
Marietta Mound encircled by a deep ditch was measured at 215 feet in diameter.  Identical measurements are found at Mounds State Park in Anderson Indiana and at New Castle Indiana.

    To the south of the smaller enclosure is a finely formed truncated mound, (a view of which is given in a subsequent Plate,) thirty feet high, and surrounded by a circular wall, constituting a perfect ellipse, the transverse and conjugate diameters of which are two hundred and thirty feet, and two hundred and fifteen feet respectively.This beautiful monument is now enclosed in the public cemetery, and is carefully guarded from encroachment. A flight of steps ascends to its summit, on which seats are disposed, and from which a beautiful prospect is commanded. In the vicinity occur several fragmentary walls, as shown in the map.