In the eastern Ogilvie Mountains, geological mapping (1:50,000) was undertaken on map sheets 116A/10 and 11, which straddle the boundary between the Foreland and Omineca belts of the Cordilleran Orogen. The area is underlain by a diverse assemblage of epicontinental and miogeoclinal sediementary, and subordinate volcanic and intrusive rocks, ranging in age from Early Proterozoic to Triassic. These rocks represent most of the geological history of the northern Cordilleran miogeocline and its supracrustal basement.