Fig. 13.—A gateway of octagon, looking inward.

The circular structure E is undoubtedly one of the best preserved and most imposing in the State. There are many enclosing larger areas, but none more clearly defined. At the entrance, which is towards the east, the ends of the walls curve outwards, for the distance of a hundred feet, leaving a passageway eighty feet wide, between the deep ditches on either hand. Here, covered with the gigantic trees of a primitive forest, the work presents a truly grand and impressive appearance; and, in entering the ancient avenue for the first time, the visitor does not fail to experience a sensation of awe, such as he might feel in passing the portals of an Egyptian temple, or in gazing upon the silent ruins of Petra of the desert. This work is not, as has been generally represented, a true circle; its form is that of an ellipse, its diameters being twelve hundred and fifty feet, and eleven hundred and fifty feet res­pec­tive­ly. There are two or three slight ir­reg­u­lari­ties in the out­line, too trifling however to be indicated in the plan. The area of the enclosure is something over thirty acres. It is an almost perfect level, and is still covered with the original forest. Immediately in the centre of the area is a mound of singular shape, of which an enlarged plan, Fig. 12, is here given. It much resembles some of the “animal-shaped mounds” of Wisconsin, and was probably designed to represent a bird with expanded wings. It can hardly be called a mound, but is rather a group of four, so arranged and connected as to constitute an unbroken outline. Denominating the figure, for the sake of distinction, a bird, the dimensions are as follows: Length of body, one hundred and fifty-five feet; of each wing, one hundred and ten feet; between the tips of the wings, measuring in a right line, two hundred feet; width of body, sixty-three feet; of wings, in centre, forty-five feet; of same, next the body, forty feet; height of mounds composing the body, seven feet; of mounds composing the wings, five feet. The head of the bird points directly towards the entrance of the enclosure. The bearing of the body is S. 65° E. Immediately in the rear of the effigy, and one hundred feet distant, is a semi-circular embankment, about two hundred feet in length; it is but slightly elevated, and can hardly be traced; it is nevertheless exhibited in the plan. The long mound, constituting the body of the bird, has been opened. Upon examining the excavation, it was found that the structure had originally contained an altar: whether any relics were found upon it, is unknown. This feature, in conjunction with others, seems p069 to point out a religious or superstitious design to this individual structure, if not to the whole group of works with which it is connected.

Fig. 14.

Fig. 15.

Passing over the in­ter­med­iate in­tri­cate works, of which it would be futile to attempt a description, we come to the octagon and its dependencies. The angles of this octagon, it will be observed, are not coincident, although its sides are very nearly equal. At each of the angles is a gateway, which is covered upon the interior by a small, truncated pyramidal elevation, (Fig. 14,) five feet in height, and measuring eighty by one hundred feet at the base. These are placed about sixty feet interior to the walls. The area of this work, which is a rich and beautiful level, is something over fifty acres. Connected with the octagon by parallels three hundred feet long, and placed sixty feet apart, is the smaller circle F. Unlike the other circular work, this is a true circle, two thousand eight hundred and eighty feet, or upwards of half a mile in circumference. It encloses no mounds, but possesses a remarkable feature in the line of the wall, at a point immediately opposite the entrance. This consists of a crown work, (Fig. 15,) which is wholly unlike anything heretofore noticed. It would almost seem that the builders had originally determined to carry out parallel lines from this point; but after proceeding one hundred feet, had suddenly changed their minds and finished the enclosure, by throwing an immense mound across the uncompleted parts. This mound, which may be taken as constituting a part of the wall of the enclosure, is one hundred and seventy feet long, eight feet higher than the general line of the embankment, and overlooks the entire work. It has been called the “Observatory,” from this fact: it probably had some other purpose than that of a look-out, but what purpose, it is not undertaken to say. It has been pretty thoroughly excavated, but the excavations seem to have disclosed nothing, except an abundance of rough stones, which must have been brought from the creek or some other remote locality, as none are scattered over the remarkable plain upon which these works are situated. p070

Fig. 16. View of “observatory” from the interior.