Iron Mountain Bed (Miocene of the United States)

Also known as Schooner Point

Where: Lincoln County, Oregon (44.7° N, 124.1° W: paleocoordinates 44.5° N, 118.0° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Astoria Formation, Burdigalian (20.4 - 16.0 Ma)

• early Miocene

•uncomformably overlain by Depoe Bay Basalt, dated at 16 +/- 0.65, 15.2 +/- 0.6, and 14.5 +/- 1.0 Ma using KA; dates are from different localities and it is not clear which is most relevant; old constants used

•overlain by the slightly higher Cape Foulweather Basalt = Gingko Basalt, dated at 15.4 +/- 0.3 Ma (mehtod?): Prothero et al. 2001

•in a reversed polarity zone interpreted as C5Cr: Prothero et al. 2001

• bed-level stratigraphic resolution

Environment/lithology: marine; concretionary, brown, gray sandstone

• "light-brown to dark-gray sandstone nodules": Prothero et al. 2001

Size class: macrofossils

Collection methods: surface (float)

Primary reference: M. C. Coombs. 1979. Tylocephalonyx, a new genus of North American dome-skulled chalicotheres (Mammalia, Perissodactyla). Bulletin of the American Museum of Natural History 164(1):1-64 [J. Alroy/J. Alroy/M. Uhen]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 18929: authorized by John Alroy, entered by John Alroy on 26.03.1995, edited by Mark Uhen

Creative Commons license: CC BY (attribution)

Taxonomic list

• see also Munthe and Coombs 1979
Mammalia
 Carnivora -
"Pteronarctos goedertae" = Pteronarctos goedertae5, "Pteronarctos piersoni n. sp." = Pteronarctos goedertae2, "Pacificotaria hadromma n. gen. n. sp." = Pteronarctos goedertae3
"Pteronarctos goedertae" = Pteronarctos goedertae5 Barnes 1989 pinniped
several specimens in Berta 1994 have different locality descriptions, but all are about the same place
"Pteronarctos piersoni n. sp." = Pteronarctos goedertae2 Barnes 1989 pinniped
"Pacificotaria hadromma n. gen. n. sp." = Pteronarctos goedertae3 Barnes 1989 pinniped
 Carnivora - Odobenidae
Proneotherium repenningi n. gen. n. sp.7
Proneotherium repenningi n. gen. n. sp.7 Kohno et al. 1995 walrus
 Carnivora - Desmatophocidae
Desmatophoca oregonensis1 Condon 1906 pinniped
 Perissodactyla - Desmostylidae
Desmostylus hesperus6 Marsh 1888 desmostylian
 Perissodactyla - Chalicotheriidae
Tylocephalonyx sp. Coombs 1979 chalicothere
 Perissodactyla - Rhinocerotidae
Aphelops sp.8 Owen 1845 rhinoceros
"rhino"; Coombs' text post-dates Munthe and Coombs
 Cetacea - Cetotheriidae
Cophocetus oregonensis9 Packard and Kellogg 1934 whale