Phosphate occurs in an outcrop on the Alaska Highway approximately 2 kilometres east of Summit Lake (Fieldwork 1987, Figure 3-7-1, sample locality SB87-45; Open File - Phosphate Deposits in British Columbia). Similar strata are exposed 100 metres to the west.

The deposit is in the Permian Kindle Formation, part of the platformal to basinal sedimentary succession that makes up Ancestral North America (Geological Survey of Canada Maps 1343A, 1713A). Regionally, this formation is 90 to 205 metres thick and comprises siltstone, shale, calcareous siltstone and minor chert (Fieldwork 1987, page 399; Geological Survey of Canada Memoir 373). Locally, it may be thinner due to truncation by an overlying unconformity.

The outcrop is in a sequence of, from base to top, chert, shale and silty shale, and brown to grey calcareous siltstone. Overlying the chert is an interval, 5 metres thick, containing black, phosphatic laminations and lenses which contrast with the grey colour of the host shale. The phosphate mineral is unknown but may be fluorapatite or collophane. A sample taken over 2.5 metres in this material averaged 3.6 per cent P2O5 (Open File - Phosphate Deposits in British Columbia). The underlying chert is very weakly phosphatic.