AbstractDetailed gravity and resistivity surveys have been made in the Vale south of Denbigh, and from the combined interpretations a Trias isopachyte map has been produced. The gravity interpretation indicates that the en echelon faults of the western side extend across to the Vale of Clwyd fault, and separate a complementary set of en echelon synclines. These structures are systematically arranged in a pattern that may be attributed to dextral wrenching, and are discussed against a range of literature on that subject. The wrenching may have been a prolonged activity that commenced during Carboniferous times.