Dr A. S impson commented that the author’s observations emphasized the importance of polyphase folding, and the accompanying superimposition of cleavages, in the deformed Lower Palaeozoic strata south of the Highland boundary fault. It was perhaps premature to attempt a tectonic correlation with the polyphase structural sequence of the Irish sea region to the east. There was, however, a close geometrical similarity between the acute F 1 folds, with their steep axial-plane S 1 , in Murrisk and the Caledonian F 1 folds developed in the Isle of Man, in North Wales, and in the Skiddaw Slates of the Lake District. The Caledonian F 2 folds at Murrisk possessed steep to vertical axial planes. This steep disposition afforded a contrast with the F 2 folds observed in the vicinity of the Irish Sea; the latter were usually gently inclined. It was interesting to note that in both central Murrisk and in the Manx Slate Series of the Isle of Man a second metamorphism had resulted in the static overgrowth of a varied selection of porphyroblasts during the F 2 – F 3 static interval. The speaker asked the author if the effect of the static post- F 2 metamorphism was uniform throughout his area or whether the occurrence of the later minerals showed any localization that might reflect F 2 structural control? In the Irish Sea region a steep strain-slip cleavage ( S 3 ). trending to the north-western quarter and possessing a steep north-easterly dip, was widely associated with F 3 cross-folding. Had the author observed post- F 2 structures of this type in Murrisk? Had the author