Runningwater Formation

The Runningwater Formation is a geologic formation in Nebraska. It preserves fossils dating back to the Hemingfordian of the Early Miocene of the Neogene period. The sandstones and conglomerates of the formation were deposited in a fluvial environment. The formation has provided many fossil mammals.

Fossil content
Among the following fossils have been found in the formation:
 * Mammals


 * Aletomeryx gracilis
 * Arretotherium fricki
 * Barbouromeryx trigonocorneus
 * Cynarctoides acridens
 * Cynelos stenos
 * Diceratherium niobrarense
 * Daphoenodon (Borocyon) robustum
 * Desmocyon thomsoni
 * Hypertragulus minor
 * Menoceras barbouri
 * Merychyus arenarum, M. elegans
 * Metatomarctus canavus
 * Osbornodon iamonensis
 * Pseudoblastomeryx advena
 * Anchitheriomys stouti
 * Desmatippus tyleri
 * Edaphocyon lautus
 * Amphicyon galushai
 * Craterogale cf. simus
 * Leptarctus cf. ancipidens
 * Leptocyon vulpinus
 * Tephrocyon scitulus
 * Merycochoerus proprius


 * Reptiles
 * Macrochelys schmidti
 * Rhineura marslandensis
 * Sceloporus sp.