Location in the E − L_z plane of the six main groups identified in Fig. 10 together with various individual, more isolated clusters. Left: each ellipse shows the approximate locus of the six tentative main groups. Right: location of independent clusters (labelled 1, 2, 3, 4, and 68). Each substructure is colour-coded as in Fig. 10, while the independent clusters are colour-coded arbitrarily. As discussed in Sect. 5.2, substructure B occupies the region dominated by Thamnos1+2, substructure C that of Gaia-Enceladus, D corresponds to Sequoia, and E to the Helmi streams. Groups A and E overlap in the E − L_z plane, but have very different L_⊥, resulting in a large Mahalanobis relative distance, as shown in Fig. 10. The orientation of substructure F is peculiar and may indicate that its constituent clusters 65 and 66 should be treated separately.