Data sets used to suggest geochemical similarity between the St Malo migmatites and Mancellian granites (Brown & D’Lemos 1991) are reinterpreted. The samples have complex distributions with outliers. Three non-parametric tests show significant statistical differences between the samples in A12O3, CaO, K2O, Cr, Ni, Sr, Y and Zr. If outliers are culled from the samples the differences become more extreme. The differences are also apparent on both principal component and multidimensional scaling plots. Geotectonic models based on a similar petrogenesis for the two rock units (D’Lemos et al. 1992) must be able to account for these differences.