First published use as one of four members of Kootenai Formation in Glacier Co, MT on the Sweetgrass arch. Intent to name not stated. Type log tentatively chosen as the Cardinal Petroleum Swensen No. 14-10, or NESESW sec 10, T37N, R5W, Glacier Co. Occurs in the North Cut Bank field area on the northwest plunge of the North Arch in north-central MT. Is a fluviatile lake and swamp deposit that is up to 60 ft thick. Consists generally of gray to black shales and varicolored mudstone to claystone, with thin beds of silty fine-grained salt-and-pepper sandstone. Sandstones are subangular quartz with some black chert, red to amber chalcedony and a trace of green hornblende?. A 5-15 ft bright-red shale commonly found at or near the top of the Lander member. Overlies Cut Bank member of Kootenai Formation; underlies Moulton member (first used) of Kootenai Formation. Geologic map. Cross sections. [Author indicates Lander member is "Sunburst of current usage."] Of Early Cretaceous age.

Source: GNU records (USGS DDS-6; Denver GNULEX).