John Day Unit K2 (Oligocene of the United States)

Also known as Middle Roundup Flat Section

Where: Grant County, Oregon (44.7° N, 119.6° W: paleocoordinates 44.4° N, 110.7° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Turtle Cove Member (John Day Formation), Chattian (28.1 - 23.0 Ma)

• bracketed by SCLF AA dates of 27.5 Ma (Deep Creek Tuff) and 25.3 Ma (Tin Roof Tuff), but Biotite Tuff in middle of unit dated at 27.2 Ma

• member-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Primary reference: L. B. Albright, M. O. Woodburne, T. J. Fremd, C. C. Swisher, B. J. MacFadden and G. R. Scott. 2008. Revised chronostratigraphy and biostratigraphy of the John Day Formation (Turtle Cove and Kimberly Members), Oregon, with implications for updated calibration of the Arikareean North American land mammal age. 116(3):211-237 [J. Alroy/J. Alroy]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 93079: authorized by John Alroy, entered by John Alroy on 28.12.2009, edited by Terri Cleary and Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• "Entelodon imperator" is said to be "not valid"
Reptilia
 Squamata - Rhineuridae
Dyticonastis rensbergeri1 Berman 1976 worm lizard
"from late Arikareean and from the uppermost levels of the Turtle Cove Member, above the Picture Gorge ignimbrite": UCMP 76878, most of anterior half of skull; UCMP 76879, nearly complete skull with mandibles and atlas; UCMP 76880, badly eroded posterior half of skull; UCMP 76884, partial skull consisting mainly of otic-occip region; UCMP 80388, nearly complete anterior half of skull with mandibles
Mammalia
 Carnivora - Nimravidae
Pogonodon sp.2 Cope 1880 false sabre-tooth
Unit K2, Lone Rock; type of P. davisi is probably from Unit K
 Carnivora - Canidae
Cormocyon copei Wang and Tedford 1992 bone-crushing dog
Enhydrocyon sp. Cope 1879 canid
Mesocyon brachyops Merriam 1906 canid
 Carnivora - Amphicyonidae
Paradaphoenus cuspigerus Cope 1878 bear-dog
Daphoenus sp. Leidy 1853 bear-dog
 Perissodactyla - Equidae
Miohippus sp. Marsh 1874 anchitheriine horse
 Perissodactyla - Rhinocerotidae
Diceratherium sp. Marsh 1875 rhinoceros
 Artiodactyla - Hypertragulidae
Hypertragulus calcaratus Cope 1873 ruminant
 Artiodactyla - Camelidae
Paratylopus sp. Matthew 1904 camel
Gentilicamelus sternbergi3 Cope 1879 camel
 Artiodactyla - Merycoidodontidae
Merycoides sp. Douglass 1907 oreodont
Oreodontoides oregonensis Thorpe 1921 oreodont
Paroreodon parvus Thorpe 1921 oreodont
Hypsiops sp. Schultz and Falkenbach 1950 oreodont
"Merycochoerus superbus" = Promerycochoerus superbus Leidy 1870 oreodont
""Promerycochoerus" macrostegus" = Promerycochoerus superbus Leidy 1870 oreodont
 Artiodactyla - Entelodontidae
Archaeotherium caninus Troxell 1920 even-toed ungulate
 Tribosphenida - Erinaceidae
Ocajila sp. Macdonald 1963 hedgehog
 Lagomorpha - Leporidae
Palaeolagus haydeni Leidy 1856 rabbit
 Rodentia - Entoptychidae
Entoptychus sp. Cope 1878 rodent
E. basilaris and/or E. wheelerensis
 Rodentia - Florentiamyidae
Florentiamys sp. Wood 1936 rodent
 Rodentia - Cricetidae
Paciculus sp. Cope 1879 rodent
Leidymys sp. Wood 1936 rodent
 Rodentia - Allomyidae
Allomys sp. Marsh 1877 rodent
 Rodentia - Castoridae
Capacikala gradatus Cope 1878 beaver