Herald Formation
The Herald Formation is a stratigraphical unit of Late Ordovician age in the Western Canadian Sedimentary Basin. It was defined in well "Imperial Herald 1-31-1-20W2M" by the Lower Paleozoic Names and Correlations Committee of the Saskatchewan Geological Society in 1958. Lithology. The Herald Formation is composed of dolomitic limestone and dolomite, which can be microcrystalline, argillaceous or microlaminated. In the centre of the basin, it is represented by anhydrite. Distribution. The Herald Formation reaches a maximum thickness of in the Lake Alma area. Relationship to other units. The Herald Formation is disconformably overlain by  the Stony Mountain Formation and conformably overlays the Yeoman Formation. It can be correlated with the Fort Garry Member of the Red River Formation in Manitoba and in the Williston Basin. Subdivisions. In south-eastern Saskatchewan, the formation is divided in three units, corresponding to three sedimentation cycles: