Viewed as a military work, the numerous breaks or openings in the wall, marked from A. to C., constitute rather its characteristic trait. They are of various and irregular widths, and it seems most difficult to decide why they are so numerous. If designed for egress or regress, they are destitute of the principle of security, unless they were defended by other works of destructible material, which have wholly disappeared. The widest opening [of 166 feet,] opens directly north, the next in point of width [78 feet,] directly south; but in order to give these or any of the other spaces the character of entry or sally ports, and, indeed, to render the entire wall defensible, it must have had palisadoes. Immediately below the openings at E. D. C., and a part of the embankment F., there are a series of deep ravines, separated by acute ridges, which must have made this part of the work difficult of approach. In front of the great (north) opening, the ground descends gradually about seventy feet, when there is a perfect acclivity. The hill has its natural extension towards the east, for several hundred yards, in the course of which, a transverse depression in the surface separates the eastern terminus of the ridge from its crown at the site of the fort. It is not known that excavations have been made for antiquarian remains, so that there is no accessory light to be derived from this source. The entire work conforms to the genius and character of the red races who occupied the Ohio valley, and who appear to have waged battle for the possession of this valuable part of the country, prior to the era of the discovery of America, and ere the Iroquois tribes had confederated and made themselves masters of the soil. That the art of defence by field works was cultivated by the ancient American tribes, is denoted by their traditions, as well as by the present state of our antiquarian knowledge. This art did not aspire to the construction of bastions, at the intersection of two right angled lines, by means of which a length of wall might have been enfiladed with arrows. Even where the works were a square or parallelogram, of which there are one or two instances among the oldest class of forts, such an obvious advantage in defence does not appear to have occurred. Fire, and the coal chisel, or digger, were the ready means of felling trees and of dividing the trunks into suitable lengths for palisades. To heap a pile of earth _within and without_ such lines, was the mode adopted by the Tuscaroras at the siege of Naharuke, in 1712, and it is probable that this _then_ powerful and warlike nation had inherited much of the skill in fort building possessed by their northern predecessors.