As many as 37 burial Mounds were constructed by the Hopewell culture approximately 2000 years ago, one of several Native American Mound builders. The dead were buried with artifacts, indicating a religious tradition. The Hopewell culture built distinctive mounds, including burial of the deceased's ashes. Later the Dakota Indians used the same site to bury their dead after wrapping the bodies in animal skins.
Indian, Nature - Parks and Playgrounds