in 1937 dr. mary leakey excavated site i, and she discovered evidence of late iron age habitation consisting of a series of rough stone enclosures, and a number of burials. this material according to sutton belongs to the late iron age and is probably around 200 yrs old (sutton, 1987). during the 1937 excavation, leakey also discovered a much older occupation layer, dating to the late stone age. several burials were uncovered; this area is today referred to as the "neolithic mass grave" on signage at the museum.