Rocks in the area are probable Upper Proterozoic Horsethief Creek Group consisting of crystalline limestone overlain by quartz- ite and underlain by metamorphosed black argillite. The rocks are isoclinally folded, striking northwest and dipping about 50 degrees to the southwest.

"Limestone in the northwesterly limb of a fold is acutely dragfolded and appears to terminate in a series of sharp fingers about 300 metres northwest of the Mogul showing. Continuity farther to the northwest had not been established, but it is probable that the limestone is greatly thinned by squeezing. Replacement by sphalerite and galena occurs over much of this distance, in thin bands up to 10 centimetres wide, and in local aggregates of such bands across widths of a few metres. Minerali- zation is apparently concentrated in the dragfold 'fingers'" (Annual Report 1951).