The orebody lies in a dolomitized zone at the base of a limestone bed in a series of lower Cambrian sediments. The sediments are isoclinally folded and the ore is in the upper limb of the fold. The ore minerals are pale-colored iron-free sphalerite, and galena. Silver is virtually absent but cadmium is associated with the sphalerite. Pyrite and some pyrrhotite are present.The major control of ore deposition has been open and overturned folding. In places the folding is accompanied by brecciation and minor pre-mineral faulting. The ore occurs in the troughs and on the limbs of the folds. The sediments have been intruded by granite, which has formed a tactite or skarn zone beneath the ore. This zone is in places overfolded and high-grade ore occurs around the nose and within the overfold.The deposit is typical of a type of world-wide distribution normally far removed from any igneous masses. The adjacent granite is not necessarily the source of the ore solutions.Trace element analyses show considerable zinc in the overlying argillite and this is considered to be a possible source of the mineralization that has been concentrated in a favorable zone in the limestone by meteoric water.