Some have supposed that formerly the river flowed at the extremity of this graded way, and a passage way to the water was thus furnished. Squier says, in this connection: “It is sufficient to observe that the river now flows half a mile to the left, and that two terraces, each twenty feet in height, intervene between the present and the supposed ancient level of the stream. To assent to this suggestion, would be to admit an almost immeasurable antiquity to the structure under consideration.” The casual observer would say that it was intended to afford an ascent from one terrace to the other. But as the height was only seventeen feet, we can not see why it was so necessary to have a long passage way of easy grade from one terrace to the other. It was evidently built in connection with the obliterated works on the third terrace. This interesting remain is now utilized as a turnpike, and the passing traveler but little recks he is going over one of the most ancient causeways in the land. It may be that ceremonious processions, with stately tread, utilized this causeway in years long since elapsed. Speculation, always an unsafe guide to follow, is especially so in this case, and so we leave this memento of a vanished people as much an enigma to us as to its first explorers.
We have described but a few of the sacred inclosures of Ohio, but enough have been given to give us a fair idea of all. We wish now to call attention to another class of remains. We have seen how the works we have been describing are lacking in defensive qualities. This becomes more marked, when we learn there are works, beyond a doubt, defensive in character, in which advantage is taken of all circumstances which would render the chosen retreat more secure. In the first place, strong natural positions were selected. They chose for their purpose bluffy headlands leading out into the river plain. A people surrounded by enemies, or pressed by invaders, would naturally turn their attention to such heights as places susceptible of defense. Accordingly, it does not surprise us to find many heights occupied by strong and complicated works. Generally the approaches to them were rugged and steep on all but one or two sides, and there they are guarded by walls of earth or stone.