Abstract
Textural patterns characteristic of supposed pre-, post- and to a lesser extent syn-tectonic porphyroblasts are reviewed. Difficulties of interpretation arise where an Si (internal schistosity) is absent, and Se (external schistosity) behaviour adjacent to porphyroblast margins is the only available criterion; examples may be found showing truncation of Se by pre-Se porphyroblasts. Truncation and/or deflection textures are not by themselves sufficient criteria for determining the time relations of particular phases of deformation and crystallization.