To promote a wider use of S and Z buckle folds in field-based structural studies, we first formulate three conditions under which quasi-cylindrical segments of gentle to close S and Z folds indicate the sense of finite-shear components. Based on our results of shear-sense mapping, we then assess the validity of published geological hypotheses in well-exposed parts of the western Grenville Province and the Southern Appalachians. Near the Central metasedimentary belt boundary of southeastern Ontario, which is widely interpreted as a 1090–1050 Ma ductile thrust, most orogen-normal, southeasterly plunging, gentle to close folds in the main foliation prove to have S style. This attests to a regional component of orogen-parallel sinistral shear that probably postdates the ductile thrusting. In gneisses and schists of the northern Inner Piedmont, six deformation events (D 1 –D 6 ) are recognized by other workers. We focus attention mainly on early Alleghanian, orogen-parallel folds (F 3 ) and associated mineral-shape fabrics in the Salem-Sunset area, western Inner Piedmont of South Carolina. Here, the orientation and S and Z style of mesoscopic F 3 features attest to an orogen-normal component of distributed thrust shear, and thereby strengthen the case for northwest-directed displacements of ductile thrust sheets during early stages of the Alleghanian orogeny.