Fig. S1.

Multiplot of the calibrated AMS radiocarbon determinations from each site (Table S3). Where appropriate, dates are modeled using Bayesian analysis, incorporating prior information from the stratigraphic sections and observations regarding the relationship between samples within the overall stratigraphy at each site. Prior distributions (unmodeled calibrations) are shown in light shading, and posterior distributions (modeled) are shown in dark shading. Dates on African crops are shaded blue, dates on Asian crops are shaded red, and dates on other materials and boundaries are shaded gray. Calibration information is in Materials and Methods. Beta, Beta Analytic; FK, Fukuchani; JS, Juani Primary School; MGB, Mgombani; MHLK, Mahilaka; OxA, Oxford Radiocarbon Accelerator Unit; UU, Unguja Ukuu; Wk, University of Waikato Radiocarbon Facility.