Assuming the works of Aztalan and the animal-mounds of Wisconsin to belong to the same period: Mr. Lapham assigns the conical mounds to a later era. These he regards as built for sepulchral purposes, and exhibiting, both in construction and materials, the workmanship of a greatly inferior race of builders. Next come what are designated by the modern settlers “ancient garden beds,” consisting of low, broad, parallel ridges, as if corn had been planted in drills. They average four feet in width, and the depth of the space between them is six inches. These appearances indicate a more perfect system of agricultural operations than anything known to have been practised by the modern Indian tribes; but, at the same time, they are no less distinctly disconnected with the construction of the ancient mounds. Where these occur within a cultivated area, the parallel ridges of the old cultivators are carried across them in the same manner as over any other undulation of the ground. It is obvious, therefore, not only that the emblematic earthworks preceded them, but that they had neither sacredness nor any special significance in the eyes of the cultivators of the soil. Probably, indeed, such traces of agricultural operations belong to a greatly more modern period. What, then, are the inferences to be drawn from the ancient monuments peculiar to the territory lying immediately to the south of the great copper region of Lake Superior? They are mostly of a negative character, yet not on that account without significance. If we assume the existence of contemporary nations in Wisconsin and the Ohio Valley in the period of the Mound-Builders, the chronicles of that era exhibit them to us in striking contrast. In the one region every convenient height is crowned with the elaborate fortifications of a numerous and warlike people; while, on the broad levels of the river-terraces, ingenious geometrical structures prove their skill and intellectual development as applied to the formation of civic and temple enclosures. Their sacred and sepulchral mounds, in like manner, reveal considerable artistic skill, and a singular variety in the rites and customs exacted in the performance of their national worship. Turning to the northern area, all is changed. Along the river-terraces we look in vain for military structures. The mounds disclose no altars rich with the metallurgic or mimetic workmanship of their builders; but, on the contrary, the sole traces of imitative art occur in the external forms of earthworks, the exploration of which confutes the idea of their having been erected over either grave or altar, and reveals no other purpose of their construction.