The uppermost member of the Belly River Group (or Judith River Group), is a major geologic unit in southern Alberta. It was deposited during the Campanian stage of the later Cretaceous, between about 76.9 and 75.8 million years ago. It was deposited in alluvial and coastal plain environments. There, a fast-flowing river spread out over a flat plain. At this time, the continents were still quite close together, and tropical climates were usual.