Pennsylvanian tuffs, sediments and massive amygdaloidal basalt of the Stikine Assemblage underlie the area of the Tito showing. Intercalated volcanics and sediments are intruded by foliated diorite of Late Triassic Age and by syenite, which is probably genetically related to the Paleocene to Eocene Sloko-Hyder Plutonic Suite. A small syenite stock contains disseminated copper mineralization, likely chalcopyrite.