Chalk Cliffs South (Miocene of the United States)

Also known as CM Locality #1935, Unit 16 microfossil quarry

Where: Park County, Montana (45.8° N, 110.5° W: paleocoordinates 46.5° N, 107.2° W)

• coordinate based on political unit

When: Unit 16 Member (Hepburn's Mesa Formation), early Late Barstovian (16.0 - 13.6 Ma)

Environment/lithology: terrestrial

Size class: mesofossils

Reposited in the CM

Primary reference: D. W. Burbank and A. D. Barnosky. 1990. The magnetochronology of Barstovian mammals in southwestern Montana and implications for the initiation of Neogene crustal extension in the northern Rocky Mountains. Geological Society America Bulletin 102 [J. Alroy/J. Alroy/J. Ju]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 18848: authorized by John Alroy, entered by John Alroy on 18.02.1993

Creative Commons license: CC BY (attribution)

Taxonomic list

• single locality near base of section
Mammalia
 Rodentia - Cricetidae
Copemys sp. Wood 1936 mouse
 Rodentia - Aplodontidae
Ansomys hepburnensis n. sp.3 Hopkins 2004 mountain beaver
Tardontia sp. Shotwell 1958 mountain beaver
 Rodentia - Sciuridae
Spermophilus sp. Cuvier 1825 ground squirrel
"Tamiini indet." = Marmotini1 squirrel
Petauristodon sp. Engesser 1979 squirrel
 Rodentia -
Geomyoidea indet.2 Bonaparte 1845 rodent
 Rodentia - Eomyidae
Pseudotheridomys sp. Schlosser 1926 rodent
Leptodontomys sp.1 Shotwell 1956 rodent
 Rodentia - Geomyidae
Mojavemys sp. Lindsay 1972 pocket gopher
 Rodentia - Heteromyidae
Cupidinimus sp. Wood 1935 rodent
possibly two species: Carrasco 1998
Perognathinae indet.1 Coues 1875 rodent
Lignimus sp. Storer 1970 rodent
probably OK
 Rodentia - Mylagaulidae
Mylagaulidae indet.1 Cope 1881 rodent
 Rodentia - Zapodidae
Zapodidae indet.1 Coues 1875 jumping mouse
 Lagomorpha - Leporidae
 Lagomorpha - Ochotonidae
Oreolagus sp. Dice 1917 pika
 Perissodactyla - Equidae
Equinae indet.1 Steinmann and Döderlein 1890 horse
 Tribosphenida - Proscalopidae
Mesoscalops sp. Reed 1960 placental