Belmont Grade ( of the United States)

Also known as UNSM Dw-123

Where: Dawes County, Nebraska (42.6° N, 103.3° W: paleocoordinates 43.4° N, 98.3° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Coffee Mill Butte Beds Formation (Arikaree Group), Harrisonian (24.8 - 20.4 Ma)

• "late late Arikareean" (= Harrisonian)

• bed-level stratigraphic resolution

Environment/lithology: eolian; volcaniclastic, shelly/skeletal, brown sandstone

• "lens of fragmentary bone/tooth 'puddingstone'... absence of fluvial bedding... 10 m interval... is characterized by 1.8 m beds of brown, well sorted, very fine-grained, eolian volcaniclastic sandstone bounded by calcareous ledges... A single helical burrow (Daemonelix) [was] discovered near the base of this unit"

Size class: mesofossils

Reposited in the UNSM

Collection methods: quarrying,

• "in situ concentration of vertebrate debris... Less than 2.3 kg of concentrate, composed of roughly 25 percent vertebrate tooth and bone fragments... microfauna. Reptile elements including dentaries were abundant, however, no fish, amphibian, or bird remains were recovered. Small mammals are represented by 11 jaw framgents with one or more teeth and 207 isolated cheek teeth."

Primary reference: B. E. Bailey. 2004. Biostratigraphy and biochronology of early Arikareean through late Hemingfordian small mammal faunas from the Nebraska Panhandle and adjacent areas. Paludicola 4(3):81-113 [J. Alroy/J. Alroy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 69806: authorized by John Alroy, entered by John Alroy on 07.03.2007

Creative Commons license: CC BY (attribution)

Taxonomic list

• fauna apart from mammals not discussed
 Rodentia - Cricetidae
Leidymys sp. Wood 1936 mouse
 Rodentia - Sciuridae
"Tamiini indet." = Marmotini
"Tamiini indet." = Marmotini squirrel
 Rodentia - Geomyidae
Entoptychus grandiplanus Korth 1992 pocket gopher
 Rodentia - Florentiamyidae
Hitonkala sp. Macdonald 1963 rodent
Florentiamys sp. Wood 1936 rodent
 Rodentia - Heteromyidae
cf. Mookomys sp. Wood 1931 rodent
Dikkomys matthewi Wood 1936 rodent
Proheteromys sp. Wood 1932 rodent
 Rodentia - Castoridae
Palaeocastor sp. Leidy 1869 beaver
 Rodentia - Mylagaulidae
Promylagaulus riggsi McGrew 1941 rodent
 Rodentia - Zapodidae
Schaubeumys sp. Wood 1935 jumping mouse
 Lagomorpha - Leporidae
? Archaeolagus sp. Dice 1917 rabbit
 Lagomorpha - Ochotonidae
Gripholagomys lavocati Green 1972 pika
 Lipotyphla - Erinaceidae
Parvericius sp. Koerner 1940 hedgehog
 Lipotyphla - Talpidae
? Scalopoides sp. Wilson 1960 mole
 Tribosphenida - Proscalopidae
Proscalops secundus Matthew 1909 placental
 Theriiformes - Herpetotheriidae
Herpetotherium youngi McGrew 1937 marsupial