be found to the eastward of the water-shed between the Mississippi and the Atlantic, in the States of Pennsylvania, New York, or Virginia; and they have been rightly designated, from their chief site, the Ancient Monuments of the Mississippi Valley, including those of its tributaries, and especially of the valley of the Ohio. There their localities fully accord with those which, in the primitive history of the Old World, reveal the most abundant traces of an aboriginal population, in their occupation of the broad alluvial terraces, or “river bottoms,” as they are styled. To the north the memorials of an ancient population are of a different character; and the earthworks in the vicinity of the Great Lakes must be classed by themselves, as indicating distinct customs and rites. The remarkable works thus traceable over so large an extent of the North American continent admit of being primarily arranged into the two subdivisions of Enclosures and Mounds, and those again embrace a variety of works evidently designed for very different uses. Under the first of these heads are included the fortifications or strongholds; the sacred enclosures, destined, as is assumed, for religious rites; and numerous miscellaneous works of the same class, generally symmetrical in structure, but the probable use of which it is difficult to determine. The second subdivision embraces the true mound-buildings, including what have been specially designated sacrificial, sepulchral, temple, and animal-mounds. All partake of characteristics pertaining to a broad level country; but this is nowhere so strikingly apparent as where mounds seem to have been purposely erected as observatories or points of sight from whence to survey the works elaborated on a gigantic scale on the level plain. In addition to the striking features which their external aspect exhibits: wherever they have been excavated interesting relics of the ancient builders have been disclosed, adding many graphic illustrations of their social condition, and of the artistic and industrial arts of the period to which they pertain.