"In both areas two relatively rigid nappes were thrust one after the other over the surface of the earth to their present positions. In both areas the lower of the two nappes was emplaced first and was subjected to erosion giving rise to sediments which were deposited on the nappes (Phyllite group of Shetland and the Valdres sparagmites of Norway). These sedimentary groups had a similar history of formation, deformation, and metamorphism, but differed somewhat in materials because the source rocks were different, although several strikingly similar rock types are present as pebbles in both areas. The remains of the first nappe and the newly deposited sediments were overrun by the second nappe in both areas. The emplacement of these nappes gave rise to considerable deformation and metamorphism in the underlying rocks. If the metamorphic rocks of Shetland are of Caledonian age, as seems likely, then it is possible that the Valdres sparagmites and the Phyllite group are stratigraphically equivalent; they are certainly tectonically equivalent."