[3] The Toad and Grayling strata have yielded fossils of marine organisms, including ammonites, brachiopods, and bivalves.

The overlying Toad Formation is more calcareous and less dolomitic than the Grayling.

It consists of dark grey calcareous siltstone and silty limestone, with minor amounts of silty dolomite and calcareous sandstone and, in the lower part, minor thin, randomly dispersed lenses and nodules of phosphate.

It is equivalent to the lower Montney Formation in the subsurface of the Peace River plains[2] and to the Phroso Siltstone Member of the Sulphur Mountain Formation in west-central and southwestern Alberta.

North of the Peace River it is overlain, possibly unconformably, by the Ludington Formation, and in the Liard River area it is unconformably overlain by the Fort St. John Group.