The character of this structure is too obvious to admit of doubt. The position which it occupies is naturally strong, and no mean degree of skill is employed in its artificial defences. Every avenue is strongly guarded. The principal approach, the only point easy of access, or capable of successful assault, is rendered doubly secure. A mound, used perhaps as an alarm post, is placed at about one-fourth of the distance down the ascent; a crescent wall crosses the isthmus, leaving but [p018] narrow passages between its ends and the steeps on either hand. Next comes the principal wall of the enclosure. In event of an attack, even though both these defences were carried, there still remains a series of walls so complicated as inevitably to distract and bewilder the assailants, thus giving a marked advantage to the defenders. This advantage may have been much greater than we, in our ignorance of the military system of this ancient people, can understand. But, from the manifest judgment with which their defensive positions were chosen, as well as from the character of their entrenchments, so far as we comprehend them, it is safe to conclude that all parts of this work were the best calculated to secure the objects proposed by the builders, under the modes of attack and defence then practised.
The coincidences between the guarded entrances of this and similar works throughout the West, and those of the Mexican defences, is singularly striking. The wall on the eastern side of the Tlascalan territories, mentioned by Cortez and Bernal Diaz, was six miles long, having a single entrance thirty feet wide, which was formed in the manner represented in the supplementary plan A. The ends of the wall overlapped each other, in the form of semicircles, having a common centre.[14]
PLATE VII. “FORT ANCIENT,” WARREN COUNTY, OHIO.[15]
[Illustration: VII. Fort Ancient, East Bank of the Little Miami River, 33 miles above Cincinnati.]
One of the most extensive, if not the most extensive, work of this class, in the entire West, occurs on the banks of the Little Miami river, about thirty-five miles north-east from Cincinnati, in Warren county, Ohio. It has not far from four miles of embankment, for the most part very heavy, rising, at the more accessible points, to the height of eighteen and twenty feet. The accompanying map is from a faithful survey, made by Prof. LOCKE, of Cincinnati, and published by him amongst the papers of the American Association of Geologists and Naturalists, in [p019] 1843. One or two slight additions have been made to his map, to indicate features which may be of some importance in a consideration of the work and its character. The description of Prof. Locke, accompanying the map, though brief, and written with a view to certain geological questions, may not be omitted in this connection.