Late Neocomian Kemik Sandstone and Kongakut Formation unconformably overlie Jurassic and Triassic rocks. In the Sadlerochit Mountains areas, which may be an extension of the Barrow Arch, pebble shale (Neocomian) is overlain by about 1,600 ft (500 m) of deep-water deposits of Late Cretaceous age; Aptian and Albian rocks are either absent or are represented by a thin, condensed section. Interval of organic-rich shale of probable Turonian to Coniacian age just above the pebble shale. Placement of the Cretaceous-Tertiary boundary within deep-marine deposits. Prograding deltaic deposition early in the Tertiary.--Modified journal abstract.