Paleohydrology of the Cypress Hills Formation and Flaxville Gravel

The Cypress Hills Formation and Flaxville gravel are laterally extensive deposits of gravel and conglomerate. They cap surficial erosion surfaces in southern Alberta and Saskatchewan, Canada, and northern Montana, U.S.A. As detrital sediments, their probable origin is inextricably linked with the question of transport. Most of the clasts are exotic, with the probable source areas in the Rocky Mountains of Montana or Idaho. A variety of potential sediment transport mechanisms is examined and paleohydrologic principles applied to evaluate the probable depositional environment. The probable depositional environment is of great significance in evaluating the diluvial/postdiluvial boundary in the northern Great Plains.