The Beartooth Butte Formation is a geologic formation in Wyoming. It preserves fossils dating back to the Devonian period.

The formation contains a basal limestone conglomerate overlain by evenly bedded red or gray limestones (more accurately, limy mudstones) and calcareous shales. It is a lenticular, channel-fill deposit which is some 2,500 feet (760 m) wide and 250 feet (76 m) thick at maximum. Most collections are from the talus slope. Stable oxygen and isotope data (Poulson in Fiorillo, 2000) indicate that the Beartooth Butte Formation was deposited in an estuarine environment, with the Cottonwood Canyon section being slightly less saline than the type section.

The following fossils have been reported from the formation:

Fish

Arthropods

• Acanthoscorpio mucronatus
• Branchioscorpio richardsoni
• Hydroscorpius denisoni
• Praearcturus sp.

Flora

• Psilophyton wyomingense
• Drepanophycus devonicus
• Euphyllophytina sp.
• Gosslingia sp.

Invertebrates

• Brachiopoda indet.

• List of fossiliferous stratigraphic units in Wyoming
• Paleontology in Wyoming

• Stein, W. E (2002), SUNY-Binghamton Paleobiology Collection
• Kjellesvig-Waering, E. N (1986), "A restudy of the fossil Scorpionida of the world", Palaeontographica Americana, 55: 1–287