Applicability and Limitations of Petrofabric Analysis Without Use of a Universal Stage. By F. J. Turner, University of Otago. [Read before the Otago Branch, April, 1940; received by the Editor, March 11, 1940; issued separately, September, 1940.] Introduction. In several recent papers on metamorphic rocks of southern New Zealand (Turner, 1936, 1938, 1938a, 1938b), the writer has given statistical analyses of orientation of grains of quartz and muscovite, based on simple microscopic measurements not involving use of a universal stage. The method employed (see Turner, 1938, p. 445) briefly may be summarised thus: Sections are cut at right angles to each of three mutually perpendicular reference axes which are selected provisionally as the a, b and c fabric axes. For two or three hundred grains in each section the angle is measured between a selected fabric axis lying in the plane of the section, and an easily determined crystallographic direction for the mineral in question—the slow vibration-direction Z' in quartz, the trace of the (001) cleavage in mica or chlorite. The percentage of grains in which the measured crystallographic direction makes any particular angle with the fabric axis, is now shown on curves constructed from these data, and the type and degree of preferred orientation is further brought out by correlating appropriate maxima and minima on the three curves. It is here proposed to discuss the applicability and limitations of this type of work in the light of results more recently obtained from the same rock-sections using a universal stage and following the standard procedure of Sander (1930, p. 121). Illustrative examples of quartz diagrams. The three curves of Fig. 1 illustrate the preferred orientation of quartz in a fissile granite, No. 4525, from Lake Manapouri, as determined without use of a universal stage (see Turner, 1938b, pp. 134–139 for details). In these and subsequent orientation curves the percentage of grains for which Z' falls within successive angular intervals of 10° is plotted against mean angular distance from a selected reference axis a or b. From these it is deduced that the quartz axes Z tend to lie on a broken girdle about the axis b, with strong concentrations (maxima) for directions inclined at 25° on one