At the center of the circle is an elegantly undulating earthen memorial built over the remains of a long, timber-framed building with two “wings.” This mound was nicknamed “Eagle Mound” by the first pioneers. When it was excavated in 1928, a pattern of postmolds showed a long building, with screen-walls extending from it like two wings.

Inside, a rectangular clay basin held fires, a sign of ritual activity. Scraps of shiny mica littered one end of the floor. When they were finished using the building, the people filled the fire basin with white sand and left little behind except a pair of copper shapes. They dismantled the wooden structure or burned it and covered its floor with earth. As often in this culture, such ritual mounding created a final, sacred memorial to the structure’s meaning.