With our present knowledge of the state of society among the Mound Builders, as made evident by the remains of their implements and ornaments, we are not justified in believing this part of a system of internal navigation. We have already seen that further south they sometimes surrounded their village sites with a wide and deep moat or ditch, as was observed around the inclosure containing the great mound on the Etowah. We are inclined to believe that a more careful survey would greatly modify the accounts we have of these canals, if it did not, in fact, show that they were the works of nature. According to a writer in the _American Antiquarian,_85 the whole lower part of the Mississippi Valley was abundantly supplied with canals, irrigating ditches, and evidences of a high intelligence. He speaks of observing the presence of an extensive canal a little north of the section we have described. He asserts they were dug to convey the surplus waters of the Mississippi in times of flood to the White and St. Francis Rivers, thus preventing disastrous overflows. It is needless to caution the reader against such conclusions. Our information in regard to those canals is far too limited to support the views advanced. This finishes our examination of the works of the Mound Builders. Except in the case of the more massive works, they have become obliterated, but here and there are left traces of the former presence of these now vanished people. The antiquary muses over the remains of their inclosures, their fortified places, their effigies and mounds. By the combined efforts of scholars in many departments, we may yet hope that the darkness now enshrouding this race may be dissipated, but at present our positive knowledge is very limited indeed. It is as if we were asked to reconstruct a picture which had faded in the lapse of time so that only traces here and there are visible. Here, perhaps, a hand is seen; there a piece of foliage; in one place something we think representing water, in another a patch of sky, or a mountain peak. Until a key is found which shall show us how to connect these scattered parts, our efforts are useless, since many pictures could be formed, but we have no surety we are right. So we may form mental conceptions of the Mound Builders, but they are almost as varied as the individual explorers. Science may yet discover the key which will enable us to form a clear mental conception of the race which flourished here many years ago, and left their crumbling memorials to excite the curiosity of a later people.