87 strike north 40 degrees west and dip 54 degrees northeast; veins have an average strike of north 15 degrees west and dip 60 degrees northeast) ; there has been little replacement of the wall-rocks by the veins, and beds can be matched across the veins to show no appreciable displacement parallel with the plane of the vein. There seems no reason to doubt that the veins fill tension cracks developed during the large-scale drag-folding of the lime- stone; and it is obvious that the schistosity of the recrystallized micaceous limestone antedated the development of the fractures. It would seem inconceivable that non-schistose limestone containing up to 20 per cent vein material could be metamorphosed in such a way that the limestone between the veins was recrystallized to a muscovite-bearing schistose rock with sharp boundaries against the veins while the vein material remained free from muscovite and retained its coarse ‘vein’ texture; and it is equally hard to visualize a system of stresses that would open the vein fissures at the same time as the schistosity was developed. Although the main metamorphism of the Ingenika group is thus seen to precede the development of the large folds, there was enough recrystal- lization during folding to prevent cataclasis and to relieve most internal stresses. Thus crystalloblastic quartz grains, though strained, are clear and unfractured. The dolomite (?) porphyroblasts in some of the chloritoid schists on Swannell River, near the axis of a major syncline, appear to have grown in a sheared rock; during growth they were rotated slightly, and after growth were further moved, allowing quartz to be deposited in spaces formed and protected by the displaced porphyroblasts. The development of these porphyroblasts, and of the nearby zoisite schists, may well be connected with the formation of the syncline, and thus later than the regional metamorphism. The processes by which schistosity could develop parallel with bedding have been discussed in the description of the Tenakihi group (See pages 51 to 54). The conclusion that most of the metamorphism occurred during a period of relatively gentle deformation earlier than, and independent from, that which produced the present major folds—under directed stresses probably occasioned by large rising or laterally invading intrusive masses, or by forces from a widespread irregular zone of anatexis and migmatic action, accompanied by an increase of temperature gradient due probably to the same intrusive or anatectic sources—applies equally to the Ingenika group. The greater local irregularity of the planes of schistosity in the Ingenika group than in the Tenakihi group is probably due to the greater inhomogeneity of the strata, with lenticular beds of differing competency and varying degrees of ease of recrystallization producing local differences in resistance to stress. ORIGIN The Ingenika group is characterized throughout by four dominant sedimentary rock types and their metamorphic derivatives: greywackes and subgreywackes, altered to slates, phyllites, chloritic schists, and chlorite quartzites; sandstones—impure, angular, and poorly sorted, to extremely pure, well rounded and sorted—now represented by the quartzites; con- glomerates, which are for the most part fine grained and merely a coarser phase of the subgreywackes and sandstones; and limestones, which in 78609—7