The Devereux Lake showing is located just west of the lake, 23 kilometres northwest of Victoria.

A band of fine to medium-grained, dark grey to white limestone extends for 366 metres northwest from a point 60 metres west of the west end of Devereux Lake. The limestone, hosted in the Colquitz Gneiss is exposed over an average width of 46 metres. The band, to the northwest, doubles back around the nose of an anticline that plunges steeply northwest.

The Colquitz Gneiss is thought to be the metamorphic equivalent of a silicic unit of the Paleozoic Sicker Group, the latest metamorphism having taken place in the Jurassic.