Sandstones from eight sections of the Frenchman Formation in the Cypress Hills Plateau and southern Saskatchewan, and from four sections of the Upper Member of the Edmonton Formation along the Red Deer Valley in central Alberta were studied by size analysis, thin-section petrography and heavy-mineral identification in order to compare these approximately time-equivalent units.

Frenchman sandstones are characterized by dusty-yellow to yellowish-gray color, moderate sorting, higher content of plagioclase than potassic feldspars, and a dominance of hornblende, epidote and garnet as heavy accessory minerals; the Upper Member of the Edmonton Formation is grayish white to yellowish gray, has poor sorting, a higher percentage of potassic feldspars than plagioclase, and a preponderance of garnet, apatite and zircon amongst the heavy minerals.

Size parameters suggest that the two formations were deposited under similar fluviatile conditions.

The compositions indicate that both formations had sources which were primarily sedimentary with lesser amounts of metamorphic, plutonic and volcanic rocks, but that these source areas differed in the kind of igneous material contributed. The Upper Edmonton sandstones were derived from terrains to the west of this formation. Source areas of the Frenchman sandstones are not known but may have included shield rocks to the northeast.

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The stratigraphic variation of hornblende frequencies in the Frenchman Formation may be used in correlating stratigraphic units within the formation, and the absence of hornblende and increase in tourmaline in the Ravenscrag Formation are useful criteria for differentiating this formation from the Frenchman at approximately the Tertiary-Cretaceous boundary.

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