The pipes may have been smoked for purification during rituals, and to ensure the good standing of the particular form of Native government, whether clan, lineage, or larger grouping. A number of pipes in the form of aquatic mammals were found at Mound City. They were to become important in perhaps the most significant archaeological debate of the mid-nineteenth century: were the mounds built by people related to the present-day Native population? If not, who built them? Most American antiquarians thought that the scale and magnificence of the earthworks indicated that they had been erected by an unrelated people, the 'Moundbuilders', whom the Native Indian replaced. To support their theory, they claimed that the otter pipes represented vegetarian manatees, living 1000 miles away in the seas around tropical Florida. The 'Moundbuilder Myth' eased nineteenth-century guilt at the rapidly disappearing Indian population. Just as the Indians had replaced the Moundbuilders - perhaps coming from the Old World - so Americans, it was thought, would entirely replace Indians.