 Hawley's first period (945–1030) was suggested by tree ring dates scattered throughout later parts of Chetro Ketl.Archeologists subsequently discovered that her second period (1030–90) structure was built directly over an earlier (990–1030) one-story-tall, two-room-wide row of rooms.Lekson shortened Hawley's second period to 1030–75, and subdivided it into at least eight different construction events, including the successive additions of upper stories along the main room block, running the length of the building.