RThe room 121Z designation was used to track features and deposits from an occupation perhaps earlier than the Chacoan use of Room 121W. These remains were found below the earliest Chacoan floor and extended beneath the walls of the room. Ten strata were found, including artificial fill layers used to build up the Chacoan floor, an occupational fill, feature fill, and a floor surface that extended well beyond the limits of the Chacoan room or the San Juan kiva. Four features were associated with 121Z including a hearth and three pits of unknown use.