Alsea Formation

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′N 124°00′W / 44.6°N 124.0°W
Approximate paleocoordinates	44°18′N 113°06′W / 44.3°N 113.1°W
Region	Lincoln County, Oregon
Country	United States
	Alsea Formation (the United States) Alsea Formation (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]

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: 1–9
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: 308–352
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