Astoria Formation Explained

Astoria Formation
Type:	Geological formation
Age:	Miocene
Subunits:	From top to bottom: Big Creek sandstone member Newport sandstone member Silver Point mudstone member Angora Peak sandstone member
Underlies:	Montesano Formation
Overlies:	Lincoln Creek Formation
Period:	Miocene

The Astoria Formation (formerly known as the Astoria shales) is a geologic formation in Washington state & Oregon. It preserves fossils dating back to the early to middle Miocene (but was formerly thought to date to the Oligocene).^[1]

Description

The Astoria Formation is a thick marine formation representing a near shore, relatively shallow-water shelf deposit. The formation spans a considerable amount of time, with its base considered to be lower boundary of Newportian Stage (late Early Miocene) & its top to be upper boundary of Newportian Stage (middle Middle Miocene).

Fossil content

Mammals

Carnivorans

Genus	Species	Stratigraphy	Material	Notes	Images
Desmatophoca	D. brachycephala	East of Knappton, Washington.^[2]	Skull elements.	A desmatophocid.
	D. oregonensis	Iron Mountain Bed & an unspecified horizon.^[3]	Multiple specimens.	A desmatophocid.
Enaliarctos	E. emlongi	South of Big Creek, Lincoln County, Oregon.^[4]	USNM 250345.	A pinnipedimorph, may instead be from the Nye Mudstone.
	E. sp.	Iron Mountain bed, Lincoln County, Oregon.^[5]	Partial skeleton (UWBM 89114).	A pinnipedimorph.
Eodesmus	E. condoni	Iron Mountain Bed, Oregon.^[6]	A nearly complete cranium.	A desmatophocid.
Pacificotaria	P. hadromma	Iron Mountain bed, Lincoln County, Oregon.^[7]	Complete cranium (LACM 127973).	A pinnipedimorph.
Proneotherium	P. repenningi	Lincoln County, Oregon.^[8]	Remains of multiple individuals.	An odobenid.
Pteronarctos	P. goedertae	Lincoln County, Oregon.^[9]	Skulls.	A pinnipedimorph.

Cetaceans

Genus	Species	Presence	Material	Notes	Images
Cophocetus	C. oregonensis	North of Yaquina Bay.	Associated skull, jaws & skeletal elements.	A baleen whale.
Dilophodelphis	D. fordycei	Nye Beach, Oregon.^[10]	USNM 214911.	A platanistid.
Wimahl	W. chinookensis	Washington State^[11]		A kentriodontid.
Zarhinocetus	Z. donnamatsonae	Near Elma, Washington.^[12]	UCMP 86139.	An allodelphinid.

Perissodactyls

Genus	Species	Presence	Material	Notes	Images
Aphelops	A. sp.		Fragment of skull (USNM 187123).	A rhinoceros.
Tylocephalonyx	T. sp.	Iron Mountain Bed, Lincoln County, Oregon.^[13]	A skull (NMNH 187129).	A chalicothere.

Cartilaginous fish

Genus	Species	Presence	Material	Notes	Images
Carcharodon	C. megalodon	North of Newport, Oregon.^[15]		Species reassigned to the genus Otodus.
Cetorhinus	C. piersoni	North of Newport, Oregon.^[16]	Teeth.	A basking shark.
Cosmopolitodus	C. hastalis	Coos Bay, Oregon.	A tooth.	A lamnid shark.
	C. planus?	North of Newport, Oregon.		A lamnid shark.
Galeocerdo	G. cf. aduncus	North of Newport, Oregon.		A requiem shark.
Hexanchus		North of Newport, Oregon.		A cow shark.
Isurus	I. hastalis	Coos Bay, Oregon.	A tooth.	Species reassigned to Cosmopolitodus.
I. planus?	North of Newport, Oregon.		Species reassigned to Cosmopolitodus.
Myliobatis		North of Newport, Oregon.		An eagle ray.
Otodus	O. megalodon	North of Newport, Oregon.		Originally reported as Carcharodon megalodon.

See also

• List of fossiliferous stratigraphic units in Oregon
• Paleontology in Washington (state)
• List of fossiliferous stratigraphic units in Washington
• Paleontology in Oregon

References

• Web site: Fossilworks: Gateway to the Paleobiology Database. ((Various Contributors to the Paleobiology Database)). 17 December 2021.
• Book: Moore, E.. 1963. Miocene marine mollusks from the Astoria formation in Oregon. Professional Paper . 10.3133/PP419. 127613845 . free.
• 1974. Stratigraphy and sedimentation of the Onion Peak area, Clatsop County, Oregon. en-gb.

Notes and References

1. Web site: Geolex — Astoria publications . 2022-12-19 . ngmdb.usgs.gov.
2. Barnes . Lawrence G. . 1987-06-18 . An Early Miocene pinniped of the genus Desmatophoca (Mammalia: Otariidae) from Washington . Contributions in Science . 382 . 1–20 . 10.5962/p.208126 . 198245103 . 0459-8113. free .
3. Ray . Clayton E. . 1976 . Fossil Marine Mammals of Oregon . Systematic Zoology . 25 . 4 . 420–436 . 10.2307/2412515 . 2412515 . 0039-7989.
4. Berta . Annalisa . 1991 . New Enaliarctos* (Pinnipedimorpha) from the Oligocene and Miocene of Oregon and the Role of "Enaliarctids" in Pinniped Phylogeny . Smithsonian Contributions to Paleobiology . 69 . 69 . 1–33 . 10.5479/si.00810266.69.1. 10088/19145 .
5. Poust . Ashley . Boessenecker . Robert . 2018 . Expanding the geographic and geochronologic range of early pinnipeds: new specimens of Enaliarctos from Northern California and Oregon . Acta Palaeontologica Polonica . 63 . 10.4202/app.00399.2017. 55978096 . free .
6. Tate-Jones . M. Kellum . Peredo . Carlos M. . Marshall . Christopher D. . Hopkins . Samantha S. B. . 2020-07-03 . The Dawn of Desmatophocidae: A New Species of Basal Desmatophocid Seal (Mammalia, Carnivora) from the Miocene of Oregon, U.S.A. . Journal of Vertebrate Paleontology . en . 40 . 4 . e1789867 . 10.1080/02724634.2020.1789867 . 2020JVPal..40E9867T . 224935328 . 0272-4634.
7. Barnes . Lawrence G. . 1992-04-07 . A new genus and species of Middle Miocene enaliarctine pinniped (Mammalia, Carnivora, Otariidae) from the Astoria Formation in coastal Oregon . Contributions in Science . 431 . 1–27 . 10.5962/p.208159 . 199822990 . 0459-8113. free .
8. Deméré . Thomas A. . Berta . Annalisa . 2001-07-20 . https://doi.org/10.1671/0272-4634(2001)021[0279:AROPRF2.0.CO;2 A reevaluation of Proneotherium repenningi from the Miocene Astoria Formation of Oregon and its position as a basal odobenid (Pinnipedia: Mammalia) ]. Journal of Vertebrate Paleontology . 21 . 2 . 279–310 . 10.1671/0272-4634(2001)021[0279:AROPRF]2.0.CO;2 . 88095414 . 0272-4634.
9. Book: Berta, Annalisa . New specimens of the Pinnipediform Pteronarctos from the Miocene of Oregon . 1994 . Smithsonian Institution Press . Washington, D.C.
10. Boersma . Alexandra T. . McCurry . Matthew R. . Pyenson . Nicholas D. . May 2017 . A new fossil dolphin Dilophodelphis fordycei provides insight into the evolution of supraorbital crests in Platanistoidea (Mammalia, Cetacea) . Royal Society Open Science . 4 . 5 . 170022 . 10.1098/rsos.170022 . 28573006 . 5451807 . 2017RSOS....470022B . 2054-5703.
11. Peredo . Carlos Mauricio . Uhen . Mark D. . Nelson . Margot D. . 2018-03-04 . A new kentriodontid (Cetacea: Odontoceti) from the early Miocene Astoria Formation and a revision of the stem delphinidan family Kentriodontidae . Journal of Vertebrate Paleontology . en . 38 . 2 . e1411357 . 10.1080/02724634.2017.1411357 . 2018JVPal..38E1357P . 89965454 . 0272-4634.
12. Toshiyuki . Kimura . Barnes . Lawrence G. . March 2016 . New Miocene fossil Allodelphinidae (Cetacea, Odontoceti, Platanistoidea) from the North Pacific Ocean . Bull.Gunma Mus.Natu.Hist. . 20 . 1–58.
13. Coombs . Margery Chalifoux . 1979 . Tylocephalonyx, a new genus of North American dome-skulled chalicotheres (Mammalia, Perissodactyla). . Bulletin of the AMNH . en-US . 164 . 1 . 1–64. 2246/1041 .
14. Mayr . Gerald . Goedert . James L. . July 2017 . Oligocene and Miocene albatross fossils from Washington State (USA) and the evolutionary history of North Pacific Diomedeidae . The Auk . en . 134 . 3 . 659–671 . 10.1642/AUK-17-32.1 . 89636332 . 0004-8038. free .
15. Welton . Bruce J. . October 1972 . Fossil Sharks in Oregon . The Ore Bin . 34 . 10 . 161–172.
16. Welton . Bruce J. . 2015-08-21 . A New Species of Late Early Miocene Cetorhinus (Lamniformes; Cetorhinidae) from the Astoria Formation of Oregon, and coeval Cetorhinus from Washington and California . Contributions in Science . 523 . 67––89 . 10.5962/p.241294 . 242792009 . 0459-8113. free .