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).

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 StratigraphyMaterial Notes ImagesDesmatophocaD. brachycephalaEast of Knappton, Washington.Skull elements.A desmatophocid.D. oregonensisIron Mountain Bed & an unspecified horizon.Multiple specimens.A desmatophocid.EnaliarctosE. emlongiSouth of Big Creek, Lincoln County, Oregon.USNM 250345.A pinnipedimorph, may instead be from the Nye Mudstone.E. sp.Iron Mountain bed, Lincoln County, Oregon.Partial skeleton (UWBM 89114).A pinnipedimorph.EodesmusE. condoniIron Mountain Bed, Oregon.A nearly complete cranium.A desmatophocid.PacificotariaP. hadrommaIron Mountain bed, Lincoln County, Oregon.Complete cranium (LACM 127973).A pinnipedimorph.ProneotheriumP. repenningiLincoln County, Oregon.Remains of multiple individuals.An odobenid.PteronarctosP. goedertaeLincoln County, Oregon.Skulls.A pinnipedimorph.

Cetaceans Genus Species Presence Material Notes ImagesCophocetusC. oregonensisNorth of Yaquina Bay.Associated skull, jaws & skeletal elements.A baleen whale.DilophodelphisD. fordyceiNye Beach, Oregon.USNM 214911.A platanistid.WimahlW. chinookensisWashington StateA kentriodontid.ZarhinocetusZ. donnamatsonaeNear Elma, Washington.UCMP 86139.An allodelphinid.

Perissodactyls Genus Species Presence Material Notes ImagesAphelopsA. sp.Fragment of skull (USNM 187123).A rhinoceros.TylocephalonyxT. sp.Iron Mountain Bed, Lincoln County, Oregon.A skull (NMNH 187129).A chalicothere.

Birds Genus Species Presence Material Notes ImagesDiomedeidaeGen. et. sp. indet.East of Knappton, Washington.Partial skeleton (SMF Av 644).An albatross.

Cartilaginous fish Genus Species Presence Material Notes ImagesCarcharodonC. megalodonNorth of Newport, Oregon.Species reassigned to the genus Otodus.CetorhinusC. piersoniNorth of Newport, Oregon.Teeth.A basking shark.CosmopolitodusC. hastalisCoos Bay, Oregon.A tooth.A lamnid shark.C. planus?North of Newport, Oregon.A lamnid shark.GaleocerdoG. cf. aduncusNorth of Newport, Oregon.A requiem shark.HexanchusNorth of Newport, Oregon.A cow shark.IsurusI. hastalisCoos Bay, Oregon.A tooth.Species reassigned to Cosmopolitodus.I. planus?North of Newport, Oregon.Species reassigned to Cosmopolitodus.MyliobatisNorth of Newport, Oregon.An eagle ray.OtodusO. megalodonNorth 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