dalradian

A series of metamorphic rocks that are difficult to assign a position in the local stratigraphical sequence

Alternative form of dalradian.

Carrying this reasoning to its ultimate conclusion, the Dalradians can be considered as including the Central Highland Division as its basal unit and the late Proterozoic Southern Highland Group at its top (the classification adopted here; Table 2.2), covering a time span of at least 200 Ma and possibly much more.

The age of the Irish Dalradian is also not fully clear (Daly 2001).