Hominoid Cline:
A simplified view of the descent tree. While the previous looked a whole like —"oh no! we descend from 3-4 different ancient Eurasian proto-groups! we're so hecking mixed!"— what you should actually see is that these proto-groups were very closely related, in direct genetic continuity along the hominid cline.

All modern Europeans descend from these 4 groups, which could easily be considered a single drifted ancient group.