FIG. 20. A in Allostratigraphy And Biostratigraphy Of The Upper Cretaceous (Coniacian-Santonian) Western Canada Foreland Basin

FIG. 20. A. The upper part of the Marshybank Member at the Bighorn Dam section (fig. 7). Surface CS23, which is mantled with chert and siderite pebbles, marks a maximum regressive surface and is overlain by four subtle upward-coarsening successions culminating in surface SS0. B. Upper part of the Marshybank Member exposed on the Bighorn River (fig. 7) showing bioturbated sandy siltstone grading up into weakly stratified silty sandstone, the top of which is marked by surface CS23.