Sandstone, light- to medium-gray, in beds up to 1 m thick. Unit contains abundant amalgamated graded beds, abundant flutes and grooves, and well developed Bouma sequences. Sand-sized grains, in declining order of abundance, are quartz, chert, and feldspar. Weathers reddish brown, forms resistant ridges or spurs on valley walls. Well exposed at type locality in Kurupa Hills and in Akmalik Creek in the Killik River quadrangle. Contains abundant plant fossils, particularly near top of formation, and has scattered brachiopods near Otuk Creek in the western Killik River quadrangle. Thickness less than 40 m, grades downward into Hunt Fork Shale (unit Degh; Mull and others, 1994). Unit is primarily mapped in the central Brooks Range. Also included here on the basis of lithologic similarity are rocks mapped by Brosgé and others (1979) as the shale and sandstone member of the Kayak Shale in the Philip Smith Mountains quadrangle