To date, no amphibian fossils are known from Fossil Butte. They must
have been present, as this class of animals is recorded from Devonian
rocks more than 350 million years old and from rocks younger than those
at Fossil Butte. Living amphibians are typified by frogs, toads, and
salamanders. The lack of amphibian remains at Fossil Butte is more
likely due to nondiscovery than nonexistence.