The Turnagain River occurrence is centred on the surface trace of a limestone band on the south side of the Turnagain River, about 93 kilometres east of the community of Dease Lake.

A band of limestone of the Hadrynian Espee Formation (Ingenika Group) trends south-southeast from the Turnagain River for 17.5 kilometres, with widths of up to 4 kilometres. The band is comprised of recrystallized limestone with minor sandy limestone and dolomite. The limestone is overlain by sandstone, shale and phyllite of the Stelkuz Formation (Ingenika Group) and underlain by phyllite, schist, siltstone and quartzite of the Swannell and Tsaydiz formations (Ingenika Group). Bedding strikes 138 to 143 degrees and dips 14 to 70 degrees southwest.