This article contains a list of fossil-bearing stratigraphic units in the state of Montana, U.S.
The Eagle Sandstone, originally the Eagle Formation, is a geological formation in Montana whose strata date back to the Late Cretaceous. It is a light to brownish gray to pale yellow-orange, fine-grained sandstone. It contains areas of crossbedding and local shale members. It contains large sandy calcareous concretions. Its thickness varies from 100 to 350 feet due to the lens nature of the individual sandstone layers and local interbedded sandy shale layers.
The Mission Canyon Formation is a geologic formation in Montana and Wyoming. It preserves fossils from the Mississippian period.
Toxolophosaurus was a sphenodont which lived in North America during the Early Cretaceous.
Orodrominae is a subfamily of thescelosaurid dinosaurs known from the Cretaceous of North America and Asia.
The Montana Group is a geologic group in South Dakota. It preserves fossils dating back to the Cretaceous period.
The Wolsey Shale is a geologic formation in Montana. It preserves fossils dating back to the Cambrian period.
The Amsden Formation is a geologic formation in Montana. It preserves fossils dating back to the Carboniferous period.
The Lodgepole Limestone is a geologic formation in Montana, United States. It preserves fossils dating back to the Carboniferous period.
The Shell Creek Shale is a geologic formation in Montana. It preserves fossils dating back to the Cretaceous period.
The Jefferson Formation is a geologic formation in Montana. It preserves fossils dating back to the Devonian period.
The Three Forks Shale is a geologic formation in Montana and North Dakota. It preserves fossils dating back to the Devonian period.
The Melville Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period.
The Polecat Bench Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period. The polyglyphanodontian lizard Chamops is known from this formation.
The Renova Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period.
The Tullock Formation is a geologic formation in Montana. It preserves fossils dating back to the Paleogene period.
The Park City Formation is a geologic formation in Montana and Utah. It preserves fossils dating back to the Permian period.
The Dinwoody Formation is a geologic formation in the western United States. It preserves fossils dating back to the Triassic period.
The Thaynes Formation is a geologic formation in Montana and Idaho, United States. It was recently elevated to group status, as the Thaynes Group.
The Belle Fourche Formation or Belle Fourche Shale is a fossiliferous early Late-Cretaceous geologic formation classification in Wyoming. Named for outcrops in Belle Fourche River, Wyoming, this unit name is also used in Montana, North Dakota, and South Dakota.
Hardistiella montanensis is a fossil fish and extinct species of lamprey found, dating from the Carboniferous period, at the Bear Gulch Limestone site in the U.S. state of Montana.
