Synopsis Psammitic and semi-pelitic metasediments in the Corrieyairack and Loch Killin areas form part of the Grampian Division and underlie the Dalradian Leven Schist of Glen Roy. Two stratigraphic successions, the Corrieyairack and Glenshirra Successions, have been recognized which share a common structural and metamorphic history, although they are separated by a well-defined zone of high strain, here termed the Gair-beinn Slide. An early foliation (S 1 ) associated with the development of isoclinal F 1 folds and movement on the Gairbeinn Slide, is refolded by tight near-upright, NE-SW trending major F 2 folds, in particular the Corrieyairack Syncline. These structures are refolded by open F 3 folds with variably oriented axial traces.

Summary The mineral assemblages in calc-silicates from the Killin area suggest an eastward increase in metamorphic grade. By comparing the chemistry and mineral assemblages of the calc-silicates, the isograd surfaces were defined. They were found to dip 13° west, to the east of Glen Brein, and approximately 4° east in the western part of the area. Thus a metamorphic synform is defined. The interval measured between the isograd surfaces shows that the combined thickness of the hornblende and bytownite zones is less than 1400 m, and therefore, by correlation, the kyanite zone in the Killin area cannot exceed this thickness.