Regional geologic mapping and stratigraphic studies have been completed along a transect that extends from the Alaska Range to Norton Sound. This transect provides a link between the accretionary terranes south of the Farewell fault and the enigmatic Koyukuk basin of west-central Alaska. Four qeologic providences are represented along the transect:1) in the Alaska Range segment, dissimilar Paleozoic platform and continental margin assemblages are juxtaposed along the Farewell fault; 2) in the Kuskokwim-Minchumina segment, a continental assemblage of early Paleozoic carbonate rocks rests unconformably on probable Precambrian metamorphic rocks and is overlain by late Paleozoic and Mesozoic terrigenous deposits; 3) in the Kaiyuh-Innoko segment late Paleozoic and Mesozoic ophiolite assemblages appear to have been thrust southeastward across a Precambrian and early Paleozoic metamorphic complex from a root zone at the margin of the Koyukuk basin; and 4) in the Koyukuk basin segment, Lower Cretaceous volcaniclastic deposits of probable island-arc affinities are overlain by Lower Cretaceous submarine fan turbidities and by Lower and Upper Cretaceaous shallow marine and fluvio-deltaic deposits. The stratigraphic evidence suggests that the Paleozoic continental rocks southeast of the Koyukuk basin underwent fragmentation during late Paleozoic and early Mesozoic time, and the field evidence supports an interpretation that the Koyukuk basin is underlain by a large fragment of late Paleozoic and early Mesozoic oceanic crust that was entrapped within the continent during late Mesozoic time. Collision between this fragment and this continental margin occurred during the Late Jurassic and Early Cretaceous, at which time the ophiolite thrust sheets were emplaced along the margin. Subsequently, during the Late Cretaceous and Tertiary, western Alaska was broken by a series of northwest-trending right-lateral strike-slip faults, and the western margin of the Koyukuk basin was strongly deformed by an east-west compressional event centered in the Bering Strait region.