Northwestern Lansing map area, 120 km east of Mayo, lacks known mineral occurrences yet contains upper Paleozoic stratigraphic units similar to those at volcanic-hosted and sedimentary exhalative deposits such as Marg and Macmillan Pass. Pyritic and locally baritic Earn Group and (previously unmapped) younger strata underlie most of the area. The sedimentary rocks are cleaved and folded but less strained than equivalent rocks in adjacent Mayo map area, and most contain abundant iron sulphide laminae, nodules, and replacements. A muscovite granite intrudes the grey-green phyllite. The Robert Service Thrust at the southern boundary of the Upper Paleozoic units, appears offset by steep, northwest-trending faults.