It is usually difficult to ascertain the shape of folds in multiply-deformed high-grade metamorphic gneisses and schists. If such rocks contain porphyroblasts, a new approach is possible because of the way through which porphyroblast grew was affected by crenulation versus reactivation of compositional layering. Isoclinally folded rocks in Texas Creek, Arkansas River region of Central Colorado contain relics of fold hinges; nevertheless, it is very difficult to ascertain whether they are antiforms or synforms because of the effects of younger refolding and the locally truncated nature of coarse compositional layering. Using the asymmetry of overprinting foliations relative to the five FIA sets in this region, the authors have revealed that an isoclinal fold, which was previously interpreted as a synform, is actually an antiform, which was developed during the first stage of porphyroblast growth (around 1 500 Ma).