Stelckiceras and other Gastroplitinae (Ammonitina), from the Albian (Lower Cretaceous) Fort St. John Group, Peace River area, northeastern British Columbia

Abstract

Stelckiceras Jeletzky, 1980 and Pseudopulchellia Imlay, 1961 emend. (J.A. Jeletzky in 1980) are illustrated from the Ammobaculites wenonahae Subzone of the Albian (Lower Cretaceous) Hasler Formation of the Fort St. John Group, on the Peace River in northeastern British Columbia. Species of Gastroplites McLearn, 1930, Pseudopulchellia Imlay, 1961, Pseudogastroplites Jeletzky, 1980, and Stotticeras Jeletzky, 1980 are illustrated from the Ammobaculites sp. and Haplophragmoides multiplum subzones of the subjacent Cadotte Member of the Boulder Creek Formation and the underlying Hulcross Formation. Two new species, Gastroplites bahani and Gastroplites jeletzkyi, are described. The presence of several Arctic exotic ammonites suggests that the middle Albian interior seaway was not entirely isolated from the Arctic basin. Numerous foraminifera are known to be common to both basins, and current inflow may have prevented endemic Gastroplites s.st. and Stelckiceras from migrating northward. Biostratigraphic conclusions by J.A. Jeletzky are supported by this study.