# Ash Hollow Formation

The Ash Hollow Formation of the Ogallala Group is a geological formation found in Nebraska and South Dakota. It preserves fossils dating back to the Neogene period. It was named after Ash Hollow, Nebraska and can be seen in Ash Hollow State Historical Park. Ashfall Fossil Beds State Historical Park is within this formation.

## Fossil content

| Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon | Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited. |

### Mammals
#### Bats

Bats reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Lasiurus | L. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | Distal portion of a left humerus (UNSM 100140). | A hairy-tailed bat. | |
| Myotis | M. sp. indet. | Ashfall Fossil Beds. | Cap Rock Member. | A right dentary (UNSM 27898). | A mouse-eared bat. | |

#### Carnivorans

Carnivorans reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Aelurodon | A. taxoides | Brown, Cherry, Keyapaha, Knox, Sheridan, Hitchcock & Banner counties, Nebraska. | Cap Rock & Merritt Dam Members. | Abundant remains. | A borophagine dog. |
| Barbourofelis | B. fricki | Channel deposits resting on upper part of the formation. | | | A barbourofelid. |
| Barbourofelis | B. morrisi | Cherry County, Nebraska. | Channel deposit resting unconformably on the Cap Rock Member. | Skull (F:AM 79999) and right ramus (F:AM 80000). | A barbourofelid. |
| Barbourofelis | ?B. whitfordi | Brown County, Nebraska. | Lower part of the formation. | Right ramus (UNSM 25546). | A barbourofelid. |
| Carpocyon | C. robustus | Brown & Cherry counties, Nebraska. | Merritt Dam Member. | Skull elements. | A borophagine dog. |
| Epicyon | E. haydeni | Brown, Cherry, Keith and Sheridan counties, Nebraska. | Merritt Dam Member. | Multiple specimens. | A borophagine dog. |
| Epicyon | E. saevus | Brown, Cherry, Antelope & Keith counties, Nebraska. | Cap Rock & Merritt Dam members. | Multiple specimens. | A borophagine dog. |
| Eucyon? | E.? skinneri | Hans Johnson Quarry, Cherry County, Nebraska. | Merritt Dam Member. | Partial mandible (F:AM 25143). | A canine dog. |
| Ischyrocyon | I. gidleyi | Cherry & Keyapaha counties, Nebraska; Todd, Bennett & Mellette counties, South Dakota. | Cap Rock Member. | | A bear-dog. |
| Leptarctus | L. wortmani | Nebraska & South Dakota. | | Many undescribed specimens. | A mustelid. |
| Leptocyon | L. matthewi | Cherry, Brown & Antelope counties, Nebraska. | Merritt Dam & Cap Rock members. | Skull and limb elements. | A canine dog. |
| Metalopex | M. merriami | Frontier County, Nebraska. | | Premaxilla, maxilla and ramus fragments. | A fox. |
| Paratomarctus | P. euthos | Brown & Cherry counties, Nebraska, & Todd County, South Dakota. | Cap Rock & Merritt Dam members. | Numerous specimens. | A borophagine dog. |
| Pseudocyon | P. sp. | Brown & Cherry counties, Nebraska. | Cap Rock & Merritt Dam members. | | A bear-dog. |
| Vulpes | V. stenognathus | Frontier County, Nebraska. | | Left molar (UNSM 26136). | A fox. |

#### Eulipotyphlans

Eulipotyphlans reported from the Ash Hollow Formation :
| Genus | Species | Location | Material | Notes |
| Achlyoscapter | A. sp. | Lemoyne Quarry, Keith County, Nebraska. | A right ramal fragment (UW 6670). | A talpine mole. |
| Alluvisorex | A. sp., cf. A. arcadentes | Lemoyne Quarry, Keith County, Nebraska. | UW 6734, 6735 & 7722; UNSM 27515. | A shrew. |
| Anouroneomys | A. magnus | Lemoyne Quarry, Keith County, Nebraska. | | A shrew. |
| Lemoynea | L. biradicularis | Lemoyne Quarry, Keith County, Nebraska. | | A desmanine mole. |
| Limnoecus | cf. L. sp. | Lemoyne Quarry, Keith County, Nebraska. | UW 6708 & 6739. | A medium-sized shrew. |
| Sorex | S. edwardsi | Lemoyne Quarry, Keith County, Nebraska. | | A medium-sized shrew. |
| Sorex | S. yatkolai | Lemoyne Quarry, Keith County, Nebraska. | UW 6731 (fragment of left ramus), 6732 & 6733. | A diminuitive shrew. |
| Sorex | S. sp. | Lemoyne Quarry, Keith County, Nebraska. | UW 6736, 6737 & 6738. | Probably a new species of shrew, larger than S. edwardsi. |
| Talpinae | Undetermined genus & species 1 | Lemoyne Quarry, Keith County, Nebraska. | 2 teeth (UW 6671 & 10527). | A mole. |
| Talpinae | Undetermined genus & species 2 | Lemoyne Quarry, Keith County, Nebraska. | Teeth (UW 10521, 10522, 10523, 10524, 10525 & 10526). | A mole. |
| Talpinae | Undetermined genus & species 3 | Lemoyne Quarry, Keith County, Nebraska. | An isolated right molar (UW 6675). | A mole. |

#### Lagomorphs

Lagomorphs reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Alilepus | A. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Mandible and teeth. | A leporid. |
| Hesperolagomys | H. sp., cf. H. galbreathi | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | A premolar (UNSM 101709). | A pika. |
| Hypolagus | H. cf. H. vetus | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | A right premolar (UNSM 101749). | A leporid. |
| Pronotolagus | P. whitei | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | An isolated premolar (UNSM 101675). | A leporid. |
| Russellagus | R. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Lower molariform teeth. | A pika. |

#### Rodents

Rodents reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Ammospermophilus | A. junturensis | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Mandible and teeth. | An antelope squirrel. |
| Antecalomys | A. phthanus | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth and mandibles. | A sigmodontine, and the most common fossil cricetid from Pratt Quarry. |
| Ceratogaulus | C. anecdotus | Brown County, Nebraska. | Merritt Dam & Cap Rock members. | Skulls, teeth and some postcranial remains. | A mylagaulid. |
| Copemys | C. mariae | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Mandibles. | A cricetid. |
| Copemys | C. pisinnus | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Mandibles and a maxilla. | A cricetid. |
| Copemys | C. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | An isolated right molar (UNSM 101560). | A cricetid. |
| Cupidinimus | C. prattensis | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | A right mandible (UNSM 101501). | A dipodomyine. |
| Dipoides | D. tanneri | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | A little worn premolar (UNSM 101612). | A castorid. |
| Eucastor | E. planus | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth and a partial mandible. | Reassigned to Nothodipoides. |
| Hystricops | H. venustus | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth. | A castorid. |
| Lignimus | L. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth and mandible. | A possible harrymyine. |
| Megasminthus | M. sp. indeterminate | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Maxillae. | A jumping mouse. |
| Mioheteromys | M. sp., cf. M. agrarius | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | An isolated premolar (UNSM 101750) and a partial mandible with lower incisor (UNSM 101573). | A heteromyid. |
| Mylagaulus | M. monodon | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth, mandible and limb elements. | A mylagaulid. |
| Nothodipoides | N. planus | Brown County, Nebraska & Todd County, South Dakota. | Merritt Dam Member. | Teeth, partial mandible & partial skull. | A castorid. |
| Perognathus | P. sp. | Antelope County, Nebraska. | | Fragmentary remains within burrows. | A pocket-mouse. |
| ?Petauristodon | ?P. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | A molar (UNSM 101659). | A petauristine, may represent a new species. |
| Phelosaccomys | P. hibbardi | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth. | A possible geomyid. |
| Prodipoides | P. dividerus | Nebraska. | Merritt Dam Member. | | A castorid. |
| Protospermophilus | P. sp., cf. P. quatalensis | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | An isolated molar (UNSM 101765). | A ground squirrel. |
| Pseudotheridomys | cf. P. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | A right mandible with teeth (UNSM 101748). | An eomyid. |
| Pterogaulus | P. barbarellae | Nebraska. | Merritt Dam Member. | | A mylagaulid. |
| cf. Sciurion | cf. S. sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | An isolated left molar (UNSM 101769). | A flying squirrel. |
| Spermophilus | S. (Otospermophilus) sp. | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | Teeth and jaws. | A ground squirrel. |
| Tregomys | T. shotwelli | Pratt Quarry, Brown County, Nebraska. | Merritt Dam Member. | An isolated right molar (UNSM 101534). | A cricetid. |

#### Ungulates

Ungulates reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Calippus | C. cerasinus | Cherry County, Nebraska. | Merritt Dam Member. | Multiple specimens. | An equid. |
| Calippus | C. placidus | Minnechaduza Fauna, northern Nebraska. | Cap Rock & lower Merritt Dam members. | | An equid. |
| Cormohipparion | C. fricki | Hollow Horn Bear Quarry, Todd County, South Dakota. | | Skull elements. | An equid. |
| Cormohipparion | C. matthewi | Cherry County, Nebraska. | Merritt Dam Member. | Multiple specimens. | An equid. |
| Cormohipparion | C. occidentale | Cherry County, Nebraska. | Merritt Dam Member. | Numerous specimens. | An equid. |
| Macrogenis | M. crassigenis | Above Burge Quarry, Brown County, Nebraska. | Merritt Dam Member. | Partial skull (F:AM AINS 467-333-1). | A peccary. |
| Mckennahyus | M. parisidutrai | Cherry County, Nebraska. | Merritt Dam Member. | Skull remains. | A peccary. |
| Proantilocapra | P. platycornea | Nebraska. | Cap Rock Member. | | An antilocaprid. |
| Pseudhipparion | P. gratum | Cherry County, Nebraska. | Cap Rock & lower Merritt Dam members. | | An equid. |
| Pseudhipparion | P. skinneri | Brown & Cherry counties, Nebraska. | Merritt Dam Member. | Skull elements & teeth. | An equid also known from Florida. |
| Pseudoceras | P. potteri | Nebraska. | Merritt Dam Member. | | Junior synonym of P. skinneri. |
| Pseudoceras | P. skinneri | Nebraska. | Merritt Dam Member. | Multiple specimens. | A gelocid. |
| Pseudoceras | P. wilsoni | Nebraska. | Merritt Dam Member. | | Junior synonym of P. skinneri. |
| Skinnerhyus | S. shermerorum | Cherry County, Nebraska. | Merritt Dam Member. | Skull remains. | A peccary. |
| Tapirus | T. johnsoni | Brown (Pratt Slide), Cherry, Sheridan & Garden counties, Nebraska. | Merritt Dam Member. | Jaw elements. | A tapir. |
| Teleoceras | T. major | Ashfall Fossil Beds, Nebraska. | | Over 100 specimens. | A rhinoceros. |
| Ustatochoerus | U. major | Cherry County, Nebraska. | Upper part of the formation. | Numerous specimens. | A merycoidodontid. |
| Ustatochoerus | U. profectus | | Cap Rock Member. | Numerous specimens. | A merycoidodontid. |
| Ustatochoerus | U. skinneri | Cherry & Brown counties, Nebraska; Tripp County, South Dakota. | | Multiple specimens. | A merycoidodontid. |

#### Proboscideans

Proboscideans reported from the Valentine Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Amebelodon | A. fricki | Frontier & Garden counties, Nebraska. | | | A gomphothere. | |

### Reptiles
#### Birds

Birds reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Anas | A. greeni | Bennett County, South Dakota. | | Distal half of a right humerus. | A teal duck originally reported as Nettion greeni. |
| Anchigyps | A. voorhiesi | Near the town of Orchard, Antelope County, Nebraska. | Cap Rock Member. | Partial skeleton (UNSM 62877). | An accipitrid resembling an Old World vulture. |
| Apatosagittarius | A. terrenus | Nebraska. | | "A nearly complete tarsometatarsus with phalanges in place". | An accipitrid convergent with the secretarybird. |
| Centuriavis | C. lioae | Nebraska. | Merritt Dam Member. | An exquisitely preserved partial skeleton. | A phasianid. |
| Nettion | N. greeni | Bennett County, South Dakota. | | Distal half of a right humerus. | Lumped into the genus Anas. |

#### Crocodilians

Crocodilians reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Alligator | A. mefferdi | Cherry County, Nebraska. | Upper portion of the formation. | A well-preserved skull and jaws, with some postcranial bones. | An alligator. | |
| Crocodilia | | Antelope County, Nebraska. | Caprock Member. | 2 teeth & a dermal plate. | | |

#### Squamates

Squamates reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Agkistrodon | cf. A. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 2 trunk vertebrae (UNSM 100283 & 100284). | A pit viper. |
| Ameiseophis | A. robinsoni | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae (UNSM 100266, 100267 & 100274). | A colubrine snake. |
| Calamagras or Ogmophis | C. or O. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae (UNSM 100252, 100253 & 100259). | An erycine boa. |
| Coluber or Masticophis | C. or M. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 2 trunk vertebrae (UNSM 100271 & 100273). | A colubrine snake. |
| Colubridae | Subgen. incertae sedis | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 198 vertebrae. | Snake remains unidentifiable below the family level. |
| Crotalus | cf. C. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 2 trunk vertebrae (UNSM 100285 & 100291). | A rattlesnake. |
| Elaphe | E. cf. E. kansensis | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 2 trunk vertebrae (UNSM 101112). | A rat snake. |
| Elaphe | E. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 6 vertebrae. | A rat snake. |
| Erycinae | Gen. et. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 2 trunk vertebrae (UNSM 100255 & 100258). | An erycine boa. |
| Lampropeltis | L. aff. getula | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae (UNSM 100286, 100290 & 100293). | A kingsnake. |
| Lampropeltis | L. similis or L. triangulum | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae. | A kingsnake. |
| Micronatrix | M. juliescottae | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 4 trunk vertebrae. | A natricine snake. |
| Neonatrix | N. cf. N. infera | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae (UNSM 100287, 100288 & 100289). | A natricine snake. |
| Nerodia | N. hillmani | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 6 trunk vertebrae. | A natricine snake. |
| Nerodia | N. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A trunk vertebra (UNSM 101113). | A natricine snake. |
| Opheodrys | cf. O. sp. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A trunk vertebra (UNSM 100270). | A colubrine snake. |
| Paleoheterodon or Heterodon | P. or H. sp. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 15 vertebrae. | A hognose snake. |
| Paracoluber | P. storeri | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 2 trunk vertebrae (UNSM 100280 & 100294). | A colubrine snake. |
| Pituophis | P. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae (UNSM 100292, 100297 & 101102). | A gopher snake. |
| Sistrurus | S. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A trunk vertebra (UNSM 100251). | A rattlesnake. |
| Texasophis | T. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A trunk vertebra (UNSM 100265). | A colubrine snake. |
| Thamnophis | T. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 12 trunk vertebrae. | A garter snake. |
| Tregophis | T. brevirachis | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | 3 trunk vertebrae (UNSM 100254, 100256, 100257). | An erycine boa. |
| Tropidoclonion | cf. T. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A trunk vertebra (UNSM 100295). | A natricine snake. |
| Viperidae | Gen. et. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A trunk vertebra (UNSM 101121). | A viper, vertebra too damaged to be identified below the family level. |

#### Testudines

Testudines reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images |
| Kinosternon | K. wakeeniense | South-central Nebraska. | | | A mud turtle also found in the Ogallala Formation. | |
| Terrapene | T. sp. | Cherry County, Nebraska. | | A hyoplastron. | May represent T. ornata longinsulae or another taxon. | |

### Amphibians

Amphibians reported from the Ash Hollow Formation :
| Genus | Species | Location | Stratigraphic position | Material | Notes |
| Acris | cf. A. sp. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | One left ilium (UNSM 101143). | A cricket frog. |
| Bufo | B. pliocompactilis | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | Multiple ilia. | A true toad. |
| Bufo | B. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | Multiple ilia. | A true toad. |
| Hyla | H. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A right ilium (UNSM 101127). | A tree frog. |
| Rana | R. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | Multiple ilia. | A ranid frog. |
| Spea | S. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | One left ilium (UNSM 101128). | A spadefoot toad. |
| Tregobatrachus | T. sp. indet. | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A left ilium (UNSM 101126). | A frog of uncertain classification. |
| Varibatrachus | V. abraczinskasae | Pratt Slide, Brown County, Nebraska. | Merritt Dam Member. | A right ilium (UNSM 101129). | A frog. |

### Plants

Plants reported from the Ash Hollow Formation :
| Genus | Species | Location | Material | Notes |
| Berriochloa | B. communis | | | A stipeae grass also found in the Valentine Formation. |
| Berriochloa | B. gabeli | | Fossil anthoecia (husks). | A stipeae grass. |
| Berriochloa | B. huletti | | Fossil anthoecia (husks). | A stipeae grass. |
| Berriochloa | B. intermedia | North-central Kansas. | | A stipeae grass. |
| Biorbia | B. fossilia | | Nutlets. | A borage. |
| Cryptantha | C. coroniformis | | Nutlets. | A borage. |
| Eleofimbris | E. svensonii | | | A cyperaceaen. |
| Equisetum | E. sp. | West-central Nebraska. | Silicified leaf-sheath fragments. | A horsetail. |