Judith River Group

The Judith River Group is a group of geologic formations in western North America dating from the late Cretaceous and noted as a site for the extensive excavation of dinosaur fossils.^[1] The formation is named after the Judith River in Montana. The group is also called the Judith River Wedge.^[2] It is stratigraphically equivalent with the Belly River Group in Alberta.^[3][4]

It comprises the Judith River Formation in north central Montana, as well as the Foremost, Oldman, and Dinosaur Park formations in Alberta and Saskatchewan in Canada.^[5] The wedge is exposed discontinuously in river drainages.