A marine seismic refraction study, conducted in August 1976 by personnel from Oregon State University and the University of Connecticut between Cape Simpson and Prudhoe Bay, Alaska, provides data for analysis which yields a subsurface structural and geological cross-section of the area. The results suggest that the structural homocline which dips to the east southeast on land extends to the offshore region as well. Correlation of geologic data from wells drilled on land with the refraction data permits tentative identification of geologic sequences on the basis of their seismic velocity. This study correlates 1.60 to 1.65 km/s layers to Quaternary sediments, 1.82 to 2.51 km/s layers to Tertiary strata, 2.91 to 3.40 km/s layers to Mesozoic formations to the east and 2.99 to 4.43 km/s to Early Mesozoic formations to the west. Velocities of 5.28 to 6.08 km/s are associated with probable argillite and phyllite of the Pre-Mississippian basement. At greater depths, refractors with velocities of 6.40 to 7.07 km/s are related to crystalline material which may be silicic or mafic. No seismic velocities typical of the upper mantle are present on the record sections, but a minimum depth calculation places the Mohorovicic discontinuity deeper than 20 km. Although the observed crustal velocities are ambiguous towards theories of the origin of the Canada Basin and the tectonic history of the northern Alaska margin, they tend to favor the orocline-Rift theory of Carey (1955) over a subduction margin. / Graduation date: 1979