The third example selected involves a more complex fabric. In a schist from Waipori (No. 4487, Turner, 1938a, pp. 113–117) quartz veins 2 mm. to 20 mm. thick are regularly developed parallel to the main schistosity ab and cutting more or less perpendicularly across an older contorted set of s -surfaces. Orientation curves drawn for ab, bc and ac sections of typical veins are shown in Fig. 7, while in Fig. 10 the maxima deduced from these have been replotted on a Schmidt net. The positions of the optic axes for 400 grains of quartz in ac sections of three typical veins were measured with a universal stage and form the basis of the fabric diagram Fig. 11; Fig. 12 is a partial diagram showing the orientation of 200 grains from one of these veins. In comparing Figs. 10 and 11 it will be seen that maxima at D and E in Fig. 10 have exactly equivalent maxima in Fig. 11, while there is a submaximum roughly equivalent to H. However, there appears to be no concentration in Fig. 11 corresponding to J of Fig. 10, while a strong maximum in the lower left quadrant of Fig. 11 has been confused with H in preparing Fig. 10. The latter therefore gives only an imperfect picture of the preferred orientation of quartz in the rock. Two important conclusions not brought out in the earlier paper might logically have been deduced: the strong maxima in the bc curve of Fig. 7 as compared with the less prominent widely distributed maxima of the ac curve indicate the existence of a girdle of quartz axes more or less perpendicular to the axis b; further, the development in both ab and bc curves of sharp maxima at about 30° from c suggests that the maxima lie upon a small circle of the ac projection, not on the periphery (cf. Sander, 1930, D. 52, p. 311; Fairbairn, 1939, Figs. 5–9). In this instance the applicability of the method based on orientation curves is limited by two factors both of which were recognised at the time of writing the earlier paper (see Turner, 1938a, p. 116). In the first place, the quartz fabric is not perfectly homogeneous so that measurements from different veins will give somewhat different maxima, while, secondly, the fabric itself is so complex that the curves are in some respects ambiguous and capable of more than one interpretation. Comparison of Figs. 11 and 12 shows the extent of inhomogeneity in the quartz fabric. In Fig. 12 there is a distinct maximum near the end of the a fabric axis, which is lacking in the partial diagrams for the other veins and hence in Fig. 11. Again the strong maximum adjacent to c in the top left quadrant of Fig. 12 is reduced to a submaximum in Fig. 11. It may be noted that the ac orientation curve for Z' in quartz of the same vein as that upon which Fig. 12 is based shows somewhat similar departures from the collective curve of Fig. 7 (compare with Fig. 10 in Turner, 1938a).