At the Midas occurrence, quartz veins occupy joints and fractures within a Cretaceous syenite dyke in Lower-(?)Middle Cambrian Eager Formation argillites. Pyrite, chalcopyrite and galena are hosted by quartz stringers. Visible gold is reported locally. Dykes are highly carbonatized and locally the dyke and host sediments are silicified and carry disseminated pyrite. Dykes strike about 050 degrees and dip 55 degrees northwest.