Jay Em ( of the United States)

Where: Goshen County, Wyoming (42.0° N, 104.2° W: paleocoordinates 42.9° N, 99.2° W)

• coordinate based on political unit

When: Marsland Formation (Hemingford Group), Harrisonian (24.8 - 20.4 Ma)

• = Upper Harrison beds

• bed-level stratigraphic resolution

Environment/lithology: terrestrial; lithology not reported

Size class: macrofossils

Primary reference: J. H. Wahlert and R. A. Souza. 1988. Skull morphology of Gregorymys and relationships of the Entoptychinae (Rodentia, Geomyidae). American Museum Novitates 2922:1-13 [J. Alroy/J. Alroy/J. Marcot]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 17793: authorized by John Alroy, entered by John Alroy on 07.06.1994, edited by Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• 7 mi stretch of US 85 according to Schultz and Falkenbach 1940
possibly relevant: "Merychyus siouxensis" Schultz and Falkenbach 1947: 13 mi S of Jay Em
"Paraenhydrocyon brachypus" Wang 1994: 12 mi S of Jay Em, stratigraphic position uncertain
Mammalia
 Rodentia - Geomyidae
Gregorymys riggsi Wood 1936 pocket gopher
 Perissodactyla - Chalicotheriidae
Moropus hollandi2 Peterson 1913 chalicothere
"chalicothere" of Skinner 1968, who gives the locality as "lower part of the exposures at a site that is 1 1/2 miles west of... Jay Em"
 Perissodactyla - Rhinocerotidae
Menoceras arikarense6 Barbour 1906 rhinoceros
 Carnivora - Mustelidae
Megalictis ferox5 Matthew 1907 mustelid carnivore
"J-M District... Upper Harrison Beds"
 Carnivora - Canidae
Osbornodon brachypus9 Cope 1881 canid
2 mi S to 5 mi N of Jay Em, i.e., exact locality not known
Desmocyon thomsoni10 Matthew 1907 bone-crushing dog
"2 mi west of Jay-Em"; "Jay-Em, high in section"; "Jay-Em, high brown sand"; and "Jay-Em, below white layer"
Phlaocyon minor10 Matthew 1907 bone-crushing dog
"Jay Em Section, high"
Cynarctoides luskensis10 Wang et al. 1999 bone-crushing dog
Jay Em area, "high brown sand" in Upper Harrison Beds
 Ungulata - Merycoidodontidae
Merychyus arenarum8 Cope 1884 oreodont
"questionable level"
Merychyus minimus8 Peterson 1907 oreodont
middle and higher parts of section
Merycoides longiceps1 Douglass 1907 oreodont
Merycochoerus matthewi7 Loomis 1924 oreodont
Goshen Co.
 Ungulata - Camelidae
Stenomylus gracilis3 Peterson 1907 camel
"Marsland"; E side of road to Jay-Em, 1.4 mi W of Jay-Em, and "Jay-Em very high"; see also Frick 1937
Tanymykter brachyodontus4 Peterson 1904 camel
"east side of road to Jay-Em Goshen County"; Upper Harrison equivalent