Name formally adopted as member of Rabbit Lake Formation of Animikie Group, and type locality designated in Emily district in northeast Crow Wing Co of east-central MN (T138N, R26W) in Lake Superior region. First described by Marsden from subsurface in T138N, R26W and now extended throughout Emily area, locally into North Range and possibly South Range. Is mappable over wide area on Cuyuna Range. Author suggests thickness and extent justify formation rank within Emily area. Throughout region, has indistinct boundaries, intercalated dark-colored argillite, slate, and possible lenticular iron-rich strata. Contains some carbonaceous argillite, some with 10 percent pyrite. Iron-formation has sparse but characteristic white or light-gray chert in pea-size nodules and cm-thick beds. Differs from Trommald Formation in containing interbedded argillite or slate, having gradational contacts, and being very siliceous. Overlain by unnamed upper member and overlies unnamed lower member. Geologic map. Is middle Precambrian in age.

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