Structure The Grampian orogeny folded the sequence in mainland Scotland into a series of major tight folds with NE-SW aligned fold axes. Much of the southeastern part of the outcrop forms a part of the Tay Nappe and involves the inversion of a large part of the succession. Caledonoid faulting on NE-SW lines affects the sequence across the entire area. References External links Metamorphic rocks Geologic formations of the United Kingdom Geology of Highland (council area) Neoproterozoic Geology of Ireland Geological supergroups