A marine seismic refraction study conducted between Cape Simpson and Prudhoe Bay, Alaska, provides data for subsuface structural and geological cross sections of the western Beaufort Shelf. The results suggest that the western Beaufort shelf is undderlain by a sedimentary prism with beds dipping and prograding to the northeast. Correlation of the refraction data with wells drilled on land and offshore reflection profiles permits tentative identification of geologic sequence on the basis of their seismic velocity. This study associates near-surface velocities of 1.60-1.65 km/s with Quaternary sedimens and 1.82-2.35 km/s velocities with Tertiary strata. Velocities of 1.60-3.40 km/s are correlated to Upper Cretaceous rocks, 2.10-4.14 km/s to Lower Cretaceous beds, 5.66-5.68 km/s to Mississippian-Pennsylvanian carbonates, and 4.24-6.08 km/s to the Franklinian basement composed of argillites and phyllites. West of Cape Halkett, the sedimentary section is mainly Lower Cretaceous, whereas east of Cape Halkett, Upper Cretaceous and Tertiary strata dominate. Higher velocities (6.40-7.07 km/s) are thought to represent the crystalline basement, probably silicic in composition. Although no seismic velocities typical of the upper mantle are present on the record sections, a minimum depth calculation places the Monorovicic discontinuity no shallower than 20 km. The interpretation indicates that the stratigraphic sequence present onshore at Prudhoe continues to the offshore and implies that the western Beaufort Shelf may be a good prospect for oil. The structures derived from seismic data indicate that the Beaufort continental margin is not diffeent from Atlantic-type margins and add further evidence to the concept of a rifted and rotated Beaufort continental margin.