In central Saskatchewan, the formations of the Upper Cretaceous Colorado Group, widely known as the First and Second White Speckled Shales, and widely used as stratigraphic markers, can be distinguished readily by the assemblages of Foraminifera that they contain. The Foraminifera fall into two distinctive assemblage zones -- the Anomalinoides complanata Zone and the Hedbergella loetterlei Zone, characteristic of the First White Speckled Shale and Second White Speckled Shale respectively. Between the speckled shales, there is developed a sequence of non-calcareous, non-speckled shales, which is more or less devoid of Foraminifera and which, for a biostratigraphic sequence, is termed the Barren Zone.

Core examination and electric-log characteristics show that, over a large area of central Saskatchewan, only a single speckled shale zone is present. It can be demonstrated, by using the established faunal zones, that this single speckled zone is a product of northward merging of the First and Second White Speckled Shales of the eastern and southern part of the province.

The Foraminifera permit correlation of both the white speckled shales of Saskatchewan with the Seabee Formation in Alaska. The equivalent of the Second White Speckled Shale is in Alberta, the middle Kaskapau Formation; in Manitoba, the Favel Formation; in the United States, the Greenhorn Formation. The equivalent of the First White Speckled Shale is, in Alberta, the upper Puskwaskau Shale; in Manitoba, the Boyne Member of the Vermilion River Formation; in the United States, the Niobrara Formation.

A Turonian age is indicated by the foraminiferal fauna of the Second White Speckled Shale, and the faunal distribution supports the belief that the formation is isochronous. The First White Speckled Shale has an early to middle Santonian age in Alberta, and a middle or upper Coniacian age in Manitoba. It is, therefore, slightly diachronous.

Distribution of Foraminifera within the speckled shales and their equivalents suggests the existence of two faunal provinces in Turonian times, and three in early Senonian times.

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