Alsea Formation

Alsea Formation
Stratigraphic range: Rupelian (Whitneyan) ~33.7–30.6  Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Formation
Underlies	Yaquina Formation
Lithology
Primary	Siltstone
Other	Mudstone
Location
Coordinates	44°36′N124°00′W / 44.6°N 124.0°W / 44.6; -124.0
Approximate paleocoordinates	44°18′N113°06′W / 44.3°N 113.1°W / 44.3; -113.1
Region	Lincoln County, Oregon
Country	United States
Alsea Formation (the United States) Show map of the United States Alsea Formation (Oregon) Show map of Oregon

The Alsea Formation is a geologic formation in Oregon. It preserves fossils dating back to the Rupelian stage of the Oligocene period. ^[1]

Fossil content

The following fossils have been reported from the formation: ^[1]

Mammals

• Aetiocetus cotylalveus ^[2]
• Maiabalaena nesbittae ^[3]
• Simocetus rayi ^[4]

Fish

• Orthechinorhinus davidae ^[5]

See also

• List of fossiliferous stratigraphic units in Oregon
• Paleontology in Oregon

References

1. Alsea Formation at Fossilworks.org
2. Deméré & Berta, 2008
3. Peredo et al., 2018
4. Fordyce, 2002
5. Welton, 2016

Bibliography

• Peredo, C. M.; Pyenson, N. D.; Marshall, C. D.; Uhen, M. D. (2018), "Tooth loss precedes the origin of baleen in whales", Current Biology , 28 (24): 1–9, Bibcode:2018CBio...28E3992P, doi:10.1016/j.cub.2018.10.047, PMID   30503622
• Welton, B. J (2016), "First report of Orthechinorhinus (Squaliformes: Etmopteriidae) from the Pacific Basin; A new species from Early Oligocene rocks of Oregon, USA", Fossil Record , 5: 303–308
• Deméré, T. A.; Berta, A. (2008), "Skull anatomy of the Oligocene toothed mysticete Aetiocetus weltoni (Mammalia; Cetacea): implications for mysticete evolution and functional anatomy", Zoological Journal of the Linnean Society , 154 (2): 308–352, doi:10.1111/j.1096-3642.2008.00414.x
• Fordyce, R. E (2002), "Simocetus rayi (Odontoceti, Simocetidae, new family); a bizarre new archaic Oligocene dolphin from the eastern North Pacific", Smithsonian Contributions to Paleobiology , 93: 185–222, doi:10.5479/si.00810266.93.185