Gypsum is exposed along the north bank of a westerly flowing tributary of Joffre Creek. It varies from cream to pale grey to grey and is laminated to thin bedded. Laminations and bedding are highly contorted. Approximately 20 metres above the base of the outcrop the rock is distinctly conglomeratic in appearance. This band is 5 metres thick and consists of ovular gypsum fragments in a gypsum matrix. Selenite is locally abundant but native sulphur is absent.

The gypsum at the Joffre occurrence has a minimum thickness of 40 metres with a strike length of less than 100 metres. Bedding strikes east-northeast with shallow dips to the north.

Stratigraphic relationships are uncertain. Tentatively this unit is assigned to the Upper(?) Middle and Earlier(?) Devonian "Basal Devonian Unit" (Open File 1988-14). Most probably it is equivalent to the Devonian Burnais Formation which is host to gypsum deposits in the Stanford Range.