Contents

Hudspeth Formation

Geomorphological formation

Hudspeth Formation
Stratigraphic range: Albian-Cenomanian ~107.5–96.6 Ma PreꞒ Ꞓ O S D C P T J K Pg N [1]
Type	Geological formation
Unit of	Mitchell Group
Area	Wheeler & Lake Counties, Oregon
Lithology
Primary	Mudstone, shale
Location
Coordinates	43°18′N 120°06′W / 43.3°N 120.1°W / 43.3; -120.1
Approximate paleocoordinates	42°54′N 74°48′E / 42.9°N 74.8°E / 42.9; 74.8
Region	Pacific Northwest  Oregon
Country	United States
Hudspeth Formation (the United States) Show map of the United States Hudspeth Formation (Oregon) Show map of Oregon

The Hudspeth Formation is a Cretaceous sedimentary rock formation, found in Oregon of the United States of America. The formation dates to the Albian age of the Early Cretaceous period. During the Albian much of this formation was submerged beneath shallow seas resulting in the preservation of many marine fossils. Pterosaur, dinosaur and marine fossils have been recovered from the formation. It is intertongued with the Gable Creek Formation.^[2]

Fossil content[edit]

Vertebrates[edit]

Vertebrates of the Hudspeth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Bennettazhia[3]	B. oregonensis	Oregon		Humerus, two fused dorsal vertebrae, and a partial joint bone	ATapejaromorpha pterosaur
Ornithopoda (Mitchell ornithopod)	Indeterminate	Oregon		Toe bone and a vertebra	First dinosaur described from Oregon (not the first discovered), likely a bloated carcass swept out into the ocean from a coastline in what is now Idaho.[4] Further discoveries suggest it may have been deposited by a mudflow[5]
Ornithopoda	Indeterminate	Oregon		Vertebra	Likely the same animal as the Mitchell ornithopod.[5]
Plesiosauroidea	Indeterminate	Oregon		A partial skull	A short necked Plesiosauroidea[6]
Ichthyosauria	Indeterminate			Vertebral centra
Scapanorhynchus sp.[7]				Teeth	A shark

Ammonites[edit]

Ammonites of the Hudspeth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Brewericeras	B. hulenensis	Oregon		Shell in siderite nodules
	B. breweri	Oregon
Leconteites	L. lecontei	Oregon		Shell
Desmoceras	D. alamoense	Oregon		Siderite nodule and shells[8]	Desmoceras is one of the most common Ammonite genera to be found in the Hudspeth Formation
Anisoceras	Indeterminate	Oregon
	A. merriami	Oregon		Coiled shell
Mariella	M. oregonensis	Oregon		Siderite nodule
Anagaudryceras	Indeterminate	Oregon		Siderite nodule
Pseudohelicoceras	P. petersoni	Oregon
Mortoniceras	M. inflatum	Oregon
	M. fallax	Oregon

Other invertebrates[edit]

Other invertebrates of the Hudspeth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Pleuromya	P. russelli	Oregon
Buchia	Indeterminate	Oregon
Epiaster	E. californicus	Oregon
Trigonarca	T. jacksonensis	Oregon
Goniomya	G. vespera	Oregon
Sogdianella	S. oregonensis	Oregon
Euspira	E. conradiana	Oregon			Euspira is still extant though E. conradiana is extinct
Eucorystes	E. platys	Oregon			A type of small crab, also present in Europe

See also[edit]

• List of pterosaur-bearing stratigraphic units
• Paleontology in Oregon

References[edit]

Bibliography[edit]

• Retallack, Gregory J.; Theodor, Jessica M.; Davis, Edward B.; Hopkins, Samantha S.; Barrett, Paul Z. (2018). "First Oregon dinosaur (Ornithopoda) from Early Cretaceous (Albian) of Oregon, U.S.A." Journal of Vertebrate Paleontology. doi:10.1080/02724634.2018.1486847. S2CID 91379584.
• Fremd, Ted; Retallack, Gregory; Springer, Dale; Scotchmoor, Judy (2005). "Oregon, U.S." The Paleontology Portal. Retrieved 2020-07-04.
• Welton, B.J (1972). "Fossil sharks in Oregon". The Ore Bin. 34: 161–170.
• Gilmore, C.W (1928). "A new pterosaurian reptile from the marine Cretaceous of Oregon". Proceedings of the United States National Museum. 73 (2745): 1–5. doi:10.5479/si.00963801.73-2745.1.