It is the only known fossil of the Pterophoridae family.

All known fossils of this small mammal are restricted to teeth.

The oldest known fossils are 30 to 60 million years old and were found in the Mojave desert.

The state's only known contemporary fossils are the remains of this sea's inhabitants.

It is the only known fossil that can be definitely assigned to this genus.

The oldest known fossils are about 3.6 billion years old.

The archaeocyathids are the oldest known fossils in the state.

The remains it left behind are among the oldest known fossils in the world.

The region's first known fossils of complex life are found in the resulting formations.

The only known fossil has been given the name Elginerpeton pancheni.