The discovery of the arenaceous foraminifer Haplophragmoides gigas Cushman in the Hudson Hope area of northeastern British Columbia indicates that the Early Cretaceous (Albian) Joli Fou Sea flooded around the north side of the Peace River Arch, making an embayment that penetrated as far west as the Rocky Mountain Foothills. The microfauna of 25 genera and 46 species of arenaceous foraminifers is illustrated carrying Bathysiphon spp., Hippocrepina sp., Hyperammina spp., Lituotuba? sp., Psammosphaera spp., Reophax spp., Ammodiscus spp., Glomospira sp., Miliammina spp., Psamminopelta spp., Trochamminoides sp., Haplophragmoides spp., Ammomarginulina sp., Ammobaculites spp., Haplophragmium spp., Trochammina spp., Textulariopsis sp., Pseudobolivina spp., Plectorecurvoides sp., Verneuilina sp., Gaudryina sp., Uvigerinammina sp., Gravellina sp., and Eggerella sp.The suite occurs in the lower part of the Hasler Shale of the Fort St. John Group about 10–20 m above beds carrying a microfauna of the Ammobaculites wenonahae Subzone (= Stelckiceras liardense ammonite Zone) present in the basal portion of the Hasler Shale. The Haplophragmoides gigas Zone sensu stricto is overlain by a sequence of silty beds (Viking equivalent?), which in turn is succeeded by the Miliammina manitobensis Zone microfauna. The H. gigas assemblage has both boreal and southern aspects, suggesting a mixing of the waters from north and south as the first expression of the Colorado Sea in earliest late Albian time. The assemblage is a deep neritic one and lacks any calcareous component. Diagnostic megafauna are lacking.