Astoria Formation

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]

Astoria Formation
Stratigraphic range: Miocene
Type	Geological formation
Sub-units	From top to bottom:[1] Big Creek sandstone member Newport sandstone member Silver Point mudstone member Angora Peak sandstone member
Underlies	Montesano Formation[2]
Overlies	Lincoln Creek Formation[2]
Location
Region	Washington, Oregon
Country	United States

Description

The Astoria Formation is a thick marine formation representing a near shore, relatively shallow-water shelf deposit.^[2] 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).^[1]

Fossil content

Color key Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon		Notes Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Mammals

Carnivorans

Genus	Species	Stratigraphy	Material	Notes	Images
Desmatophoca	D. brachycephala	East of Knappton, Washington.[3]	Skull elements.[3]	A desmatophocid.
	D. oregonensis	Iron Mountain Bed & an unspecified horizon.[3][4]	Multiple specimens.[3][4]	A desmatophocid.
Enaliarctos	E. emlongi	South of Big Creek, Lincoln County, Oregon.[5]	USNM 250345.[5]	A pinnipedimorph, may instead be from the Nye Mudstone.[citation needed]
	E. sp.	Iron Mountain bed, Lincoln County, Oregon.[6]	Partial skeleton (UWBM 89114).[6]	A pinnipedimorph.
Eodesmus	E. condoni	Iron Mountain Bed, Oregon.[7]	A nearly complete cranium.[7]	A desmatophocid.
Pacificotaria	P. hadromma	Iron Mountain bed, Lincoln County, Oregon.[8]	Complete cranium (LACM 127973).[8]	A pinnipedimorph.
Proneotherium	P. repenningi	Lincoln County, Oregon.[9]	Remains of multiple individuals.[9]	An odobenid.
Pteronarctos	P. goedertae	Lincoln County, Oregon.[10]	Skulls.[10]	A pinnipedimorph.

Cetaceans

Genus	Species	Presence	Material	Notes	Images
Cophocetus	C. oregonensis	North of Yaquina Bay.[4]	Associated skull, jaws & skeletal elements.[4]	A baleen whale.
Dilophodelphis	D. fordycei	Nye Beach, Oregon.[11]	USNM 214911.[11]	A platanistid.
Wimahl	W. chinookensis	Washington State[12]		A kentriodontid.
Zarhinocetus	Z. donnamatsonae	Near Elma, Washington.[2]	UCMP 86139.[2]	An allodelphinid.

Perissodactyls

Genus	Species	Presence	Material	Notes	Images
Aphelops	A. sp.		Fragment of skull (USNM 187123).[4]	A rhinoceros.
Tylocephalonyx	T. sp.	Iron Mountain Bed, Lincoln County, Oregon.[13]	A skull (NMNH 187129).[13]	A chalicothere.

Birds

Genus	Species	Presence	Material	Notes	Images
Diomedeidae	Gen. et. sp. indet.	East of Knappton, Washington.[14]	Partial skeleton (SMF Av 644).[14]	An albatross.

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

See also

• Earth sciences portal
• Oregon portal
• Paleontology portal

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