Remanent magnetic studies in the Lac des Mille Lacs area of northwestern Ontario have revealed unstable remanence directions in foliated Archean metavolcanics. Instabilities are of such a magnitude that remanence directions are unsuitable for the application of a fold test toward resolving the attitude of fold limbs in the highly deformed sequence of volcanic flows in this area.Measurements of magnetic susceptibility anisotropy indicate a slight preponderance of magnetic foliation over lineation. Anisotropy is due to shape effect and to stringing together of magnetic particles. A close correlation appears to exist between the attitude of structural foliation and that of susceptibility anisotropy and suggests a potential use for this property in structural mapping of metavolcanics within outcrops where foliation is scarcely visible. Distribution of the prolateness factor may be useful in deriving qualitatively, the pattern of strain distribution.