To this group of works an interest attaches similar to that of the group of works mentioned in Louisiana. We are not certain but that we catch a glimpse of it while it was yet an inhabited Indian town. This is contained in the brief accounts we have of the wanderings of the unfortunate De Soto and his command. One of the chroniclers of this expedition La Vega, describes one of the towns where the weary Spaniards rested, and which we are sure was somewhere in Northern Georgia, in such terms, mentioning the graded way leading to the top, that Prof. Thomas, who has spent some time in this investigation, thinks his description can apply only to the mound under consideration.40 Whether this conclusion will be allowed to stand, remains to be seen. But, if true, then the darkness which rests upon this aboriginal structure lifts for a moment and we see around it a populous Indian town, able to send five hundred warriors to battle. The Spaniards marched on to sufferings and death, and darkness again closed around the Etowah Mound. When the Europeans next beheld it around it was the silent wilderness; the warriors had departed; the trees of the forest overspread it.
We have now described the principal mound structures, and shown the different classes into which they are divided. But a large class of mounds are found scattered all through the Mound Builders’ territory that were probably used as signal mounds. Burial mounds were also often used for this purpose.41 This was because their location was always very favorable for signal purposes. Signaling by fire is a very ancient custom. The Indians on our western plains convey intelligence by this means at the present day. Some tribes use such materials as will cause different shades of smoke, using dried grass for the lightest, pine leaves for the darkest, and a mixture for intermediate purposes. They also vary the signal by letting the smoke rise in an unbroken column, or cover the fire with a blanket, so as to cause puffs of smoke. The evidence gathered from the position of the mounds, and traces of fire on their summit, is that the Mound Builders had a very extensive system of signal mounds.
To illustrate this system, we would state that the city of Newark, Ohio, was the site of a very extensive settlement of the Mound Builders. This settlement was in a valley, but on all the surrounding hills were located signal mounds. And it is further stated that lines of signal mounds can be traced from here as a center to other and more distant points. The large mound at Mt. Vernon, twenty miles to the north, was part of this system. As the settlements of the Mound Builders were mostly in river valleys, we would expect to find all along on the bluffs fronting these valleys traces of signal mounds. In the Scioto Valley, from Columbus to Chillicothe, a distance of about forty miles, twenty mounds “may be selected, so placed in respect to each other that it is believed, if the country was cleared of forests, signals of fire might be transmitted in a few minutes along the whole line.” Some think the chain is much more extensive than this, and that the whole Scioto Valley, from Delaware County to Portsmouth, was so provided with mounds that signals could be sent in a very few minutes the whole distance.42
The valley of the Miami River was equally well provided with signal mounds. This great mound, at Miamisburg, Ohio, rising to the height of sixty-eight feet, was one of the chain by which signals were transmitted along the valley. Not only was each river valley thus provided, but there is evidence that communication was established between different river systems, so we can easily see how quickly the invasion of their country by an enemy from any quarter would become known in widely scattered sections. Immediately across the river from Chillicothe, Ohio, on a hill nearly six hundred feet high, was located a signal mound. A fire built upon it would be visible twenty miles up the valley, and an equal distance down. It would be also visible far down the valley of Paint Creek. Some think that such a system of lofty observatories extended across the whole State of Ohio, of Indiana, and Illinois, the Grave Creek mound, on the east, the great mound at Cahokia, on the west, and the works in Ohio filling up the line. We do not believe, however, it is safe to draw such conclusions. It is doubtful whether there was any very close connection between the tribes in these several sections.
In the State of Wisconsin are found some of the most interesting remains of the Mound Builders. They are so different from the ordinary remains found elsewhere that we must admit that the people who built them differed greatly from the tribes who built the great temple mounds of the South, or the earthworks of Ohio. The remains in Wisconsin are distinguished not by their great size or height, but by their singular forms. Here the mound building instincts of the people were expressed by heaping up the earth in the shape of animals. What strange fancy it was that led them to mould the figures on the bluffy banks of the rivers and the high lands about the lakes of their country, we shall perhaps never know. That they had some design in this matter is, of course, evident, and if we would try and learn their secret, we must address ourselves to a study of the remains.