Fig. 2. Results of the statistical analysis of PXRF data from all 52 sarsen stones at Stonehenge.

(A) Results of linear discriminant analysis and (B) Bayesian principal component analysis. LD1, linear discriminant 1; PC1, principal component 1. Only selected sarsens discussed in the text are highlighted in each graphic. Covariance of the first six principal components from the BPCA is shown in fig. S1, with the respective element loadings in table S1 (see figs. S2 and S3 for BPCA results for other stones, and figs. S4 and S5 for BPCA results according to the main structural components at the monument). Ellipsoids indicate the 95% normal confidence ellipses.