Abstract

An extensive microfauna of over 19 genera and 34 species of arenaceous foraminifera belonging to the Ammobaculites wenonahae Subzone of the uppermost Middle Albian beds of the Fort St. John Group occurs in association with the ammonite Stelckiceras liardense (Whiteaves) in the basal portion of the Hasler Shale in the Hudson Hope area of northeastern British Columbia. The generic composition of the assemblage includes Hippocrepina sp., Hyperammina sp., Psammosphaera., Saccammina spp., Thuramminoides sp., Ammodiscus spp., Glomospira sp., Reophax spp., Miliammina spp., Psamminopelta sp., Haplophragmoides spp., ?Recurvoides sp., Ammobaculites spp., Haplophragmium spp., Trochammina spp., Uvigerinammina sp., Verneuilinoides spp., ?Arenobulimina sp., Pseudobolivina sp.

The microfauna occurs above the sandy equivalent of the Cadotte sandstone (lower Boulder Creek Formation) of the Fort St. John Group and about 50 m below beds carrying a microfauna similar to that of the Joli Fou Formation of eastern Alberta. The assemblage has boreal affinities, being closely related to that found on the northern (Arctic) coast of Alaska, and is diagnostic of the uppermost subzone of the Gaudryina nanushukensis Zone of the western interior plains of Canada. The assemblage is interpreted as outer neritic, although inner shelf genera have strong representation but without any calcareous component, suggesting a low pH factor.