The structural history of the area is described. Early intense deformation and syntectonic metamorphism to granulite facies (Willyama orogeny, ending approx 1500 m.y. ago) which produced widespread, flat-lying nappes was followed by later, less intense deformation which formed the major, easily recognized folds (Delamerian event; 500 m.y.). The famous Ag-Pb-Zn orebody lies in the overturned limb of a nappe and has been transported, with its enclosing rocks, several kilometres from its original point of deposition. Although there is localized structural control of the orebody, the primary control on its position is probably syngenetic.A.C.B.