CHAPTER II. EARTHWORKS—ENCLOSURES.
The Enclosures, or, as they are familiarly called throughout the West, “Forts,” constitute a very important and interesting class of remains. Their dimensions, and the popular opinion as to their purposes, attract to them more particularly the attention of observers. As a consequence, most that has been written upon our antiquities relates to them. A considerable number have been surveyed and described by different individuals, at different times; but no systematic examination of a sufficient number to justify any general conclusion as to their origin and purposes has heretofore been attempted. We have therefore had presented as many different hypotheses as there have been individual explorers; one maintaining that all the enclosures were intended for defence, while another persists that none could possibly have been designed for any such purpose. Investigation has shown, however, that while certain works possess features demonstrating incontestibly a military origin, others were connected with the superstitions of the builders, or designed for other purposes not readily apparent in our present state of knowledge concerning them.
It has already been remarked that the square and the circle, separate or in combination, were favorite figures with the mound-builders; and a large proportion of their works in the Scioto valley, and in Ohio generally, are of these forms. Most of the circular works are small, varying from two hundred and fifty to three hundred feet in diameter, while others are a mile or more in circuit. Some stand isolated, but most in connection with one or more mounds, of greater or less dimensions, or in connection with other more complicated works. Wherever the circles occur, if there be a fosse, or ditch, it is almost invariably interior to the parapet. Instances are frequent where no ditch is discernible, and where it is evident that the earth composing the embankment was brought from a distance, or taken up evenly from the surface. In the square and in the irregular works, if there be a fosse at all, it is exterior to the embankment; except in the case of fortified hills, where the earth, for the best of reasons, is usually thrown from the interior. These facts are not without their importance in determining the character and purpose of these remains. Another fact, bearing directly upon the degree of knowledge possessed by the builders, is, that many, if not most, of the circular works are perfect circles, and that many of the rectangular works are accurate squares. This fact has been demonstrated, in numerous instances, by careful admeasurements; and has been remarked in cases where the works embrace an area of many acres, and where the embankments, or circumvallations, are a mile and upwards in extent. p009
To facilitate description, and to bring something like system out of the disordered materials before us, the enclosures are, to as great a degree as practicable, divided into classes; that is to say, such as are esteemed to be works of defence are placed together, while those which are regarded as sacred, or of a doubtful character, come under another division.