This phosphate occurrence is situated on the north side of the Alaska Highway, immediately north of the more easterly of two bridges which cross the North Tetsa River, about 13 kilometres east of Summit Lake (Fieldwork 1987, Figure 3-7-1, sample locality SB87-43; Open File - Phosphate Deposits in British Columbia).

The deposit is in the Early to Middle Triassic Toad Formation, part of the platformal to basinal sedimentary succession that makes up Ancestral North America (Geological Survey of Canada Map 1713A). The formation is composed of dark grey calcareous siltstone and shale, and minor limestone and very fine grained sandstone (Geological Survey of Canada Memoir 373, Map 1343A). Most lithologies are weakly to moderately carbonaceous. Phosphate-bearing beds occur in the lower and middle parts of the formation, an interval which varies in thickness from a few tens of metres to approximately 290 metres (Fieldwork 1987, page 401; Geological Survey of Canada Bulletin 247).

The Alaska Highway showing is based on an interval of phosphatic siltstone and limestone, 2.5 metres thick, within a sequence of dark grey to black argillaceous limestone and calcareous shale. Bedding strikes 155 degrees and dips 55 degrees west. The phosphate, assumed to consist of fluorapatite (Geological Survey of Canada Bulletin 247, page 20), occurs as disseminated pellets, 0.1 millimetre across, and a few black nodules. They generally constitute less than 20 per cent of the rock, but locally may form as much as 40 per cent. The phosphatic interval averages 5.56 per cent P2O5 (Open File - Phosphate Deposits in British Columbia). Another phosphatic bed, 70 centimetres thick and 55 metres higher in the section, contains 10.12 per cent P2O5.