in the Mississippi Valley are referable to the Mound Builders. We have tried to point out the more important works that are ascribed to them. It must of necessity occur in a work of this nature that the review should be very brief, yet we have touched on the different classes of their works. But before leaving this part of our field we must mention some anomalous works, and refer to others which, if they can be relied on as works of the same people, certainly imply a great advance on their part. Our next cut is named by Mr. Pidgeon the “Sacrificial Pentagon.” Writing in 1850, he states, “This remarkable group . . . has probably elicited more numerous conjectures as to its original use than any other earth-work yet discovered in the valley of the Mississippi. . . . It is situated on the west highlands of the Kickapoo River, in Wisconsin.”76 Mr. Pidgeon claims to have discovered two of these pentagons. We are not aware that any one else has verified these discoveries, and it is difficult to decide what value to give to his writings. He claims to have made extensive researches around the head-waters of the Mississippi as early as 1840, and there to have met an aged Indian—the last of his tribe—who gave him many traditions as to the mounds in that locality. Most of our scholars think his writings of no account, whatever, and yet Mr. Conant says, “He seems to have been a thoroughly conscientious and careful observer, faithfully noting what he saw and beard.”77 Sacrificial Pentagon. We will briefly describe a few of the earth-works he mentions, notice their singular form, and give an outline of the traditions in regard to them, leaving the reader to draw his own conclusions. Of this work the outer circle is said to have been twelve hundred feet in circumference, the walls being from three to five feet in height; width on the ground from twelve to sixteen feet. The walls of the pentagon were from four to six feet high. The inner circle was of very slight elevation. The central mound was thirty-six feet in diameter. This singular arrangement of circle, pentagon, and mounds, is traditionally represented to have been a sacred national altar—the most holy one known to tradition—and no foot, save that of a priest, might pass within the sacred walls of the pentagon after its completion. The sacrifice offered on this altar was that of human life. Twice each year the offering was made.78 Festival Circle.