ABSTRACT

Lithostratigraphic nomenclature in the Upper Cretaceous Montana Group in the southern Plains of Alberta is ambiguous and confusing. The name "Belly River" has not been used consistently and has outlived its usefulness. The names "Oldman" and "Foremost" are vague, ill-defined terms whose use should be discontinued. The name "Judith River" should be employed for the entire interval between the Pakowki Formation below and the Bearpaw Formation above. It has been applied consistently to this stratigraphic interval in northern Montana and, at times, in southern Alberta, for the past 100 years and its use would serve to unify and simplify the nomenclature throughout this area.

Use of the name "Belly River" should be retained in the Foothills of southwestern Alberta, beyond the western limit of the Pakowki Formation, where the Judith River and Milk River Formations are not differentiated.