Abstract The Lewis thrust plate in Glacier National Park contains the displaced margin of the Mesoproterozoic Belt Basin, which was transported some 130 km (~80 mi) northeastward during the Late Cretaceous to late Paleocene Laramide orogeny. This two-day field trip examines the Lewis plate on an eastward transect along the Going-to-the-Sun Road, crossing the Continental Divide at Logan Pass. The trip begins in basinal facies of the Belt Supergroup, and crosses eastward into shelf facies. The shelf-to-slope transition coincides with the axis of the Akamina syncline along the Continental Divide. The trip visits classic exposures of the Lewis thrust along the Rocky Mountain front, where the lower Belt Supergroup overlies a duplex zone in the Late Cretaceous marine section.