"In both north-east Shetland and the Jotunheim area of Norway two nappes of crystalline rocks occur lying one above the other and separated in time and space by orogenic sediments. These sediments were formed in part at least by erosion of the lower, and first emplaced, of the two nappes in both areas. Later emplacement of the upper nappes caused the deformation and metamorphism of these rocks. In both Norway and Shetland large quartzite conglomerates which occur immediately beneath the upper nappes have been deformed on patterns which have been determined from a study of the pebble shapes. From these patterns in both areas it is argued that the deformation was due to flow caused by pressure differences developed in the sole of the advancing nappe and possibly to extrusion from beneath the nappe."