Whitby Mudstone

The Whitby Mudstone is a Toarcian (Early Jurassic; Falciferum-Bifrons in regional chronostratigraphy) geological formation in Yorkshire and Worcestershire, England.^[1] The formation, part of the Lias Group, is present in the Cleveland and Worcester Basins and the East Midlands Shelf.

Whitby Mudstone
Stratigraphic range: Toarcian (Falciferum-Bifrons) ~183–176 Ma PreꞒ Ꞓ O S D C P T J K Pg N
East Cliff near Whitby
Type	Geological formation
Unit of	Lias Group
Sub-units	Members: Fox Cliff Siltstone Peak Mudstone Alum Shale[note 1] Mulgrave Shale Grey Shale
Underlies	Inferior Oolite or Ravenscar Groups Or Blea Wyke, Dogger or Bridport Sand Formations
Overlies	Marlstone Rock or Cleveland Ironstone Formations
Thickness	Up to 120 m (390 ft)
Lithology
Primary	Mudstone
Other	Siltstone
Location
Coordinates	54.5°N 0.6°W / 54.5; -0.6
Approximate paleocoordinates	42.5°N 9.3°E / 42.5; 9.3
Region	Yorkshire, Worcestershire
Country	England
Extent	Cleveland & Worcester Basins & East Midlands Shelf
Type section
Named for	Whitby
Location	Coastal exposures from Hawsker Bottoms to Whitby Harbour
Whitby Mudstone (the United Kingdom) Show map of the United Kingdom Whitby Mudstone (England) Show map of England

Lithology

The formation consists of mudstone and siltstone, partly laminated and bituminous, medium to dark grey in colour, with rare fine grained calcareous sandstone beds. Limestone and phosphatic nodules are present at some levels.^[2]

Fossil content

Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus.^[3][4] One of the more notable discoveries is the skull of the pterosaur Parapsicephalus, found within the Alum Shale^{[note 2]} Member.^[5]

Vertebrates

Vertebrates of the Whitby Mudstone Formation
Genus	Species	Location	Stratigraphic position	Abundance	Notes	Images
cf. Campylognathoides	Indeterminate	Winterton	Falciferum Zone	NHMUK PV R 36712, Humerus[6]	A pterosaur
Gyrosteus	G. mirabilis	Whitby		Multiple partial skeletons[7]	A large chondrosteid acipenseriform fish
Hauffiosaurus	H. longirostris	Whitby-Saltwick	Falciferum Zone	MCZ 1033, a skeleton	A Pliosaurid
Microcleidus	M. homalospondylus	Whitby	Upper Alum Shale, Hildoceras bifrons Zone	Multiple partial skeletons	Microcleidid plesiosaur
Macrospondylus	M. bollensis		Harpoceras serpentinum Zone	Several partial skeletons	Teleosaurid
Mystriosaurus	M. laurillardi	Whitby		Skull and lower jaws[8]	Teleosaurid, formerly considered to be the holotype of "Steneosaurus" brevior
Parapsicephalus	P. purdoni	Loftus Alum Shale Quarry, Saltwick Bay (referred material)	Upper Alum Shale Member	Single partial skull lacking the snout (GSM 3166), tentantive referral of a humerus and scapulocoracoid (NHMUK PV R36634).[9]	A Rhamphorhynchid pterosaur
Pelagosaurus	P. typus	Whitby	Alum Shale		Thalattosuchian
Rhomaleosaurus	R. thorntoni	Kingsthorpe Hollow	Upper	NHMUK PV Rr4853, a single mostly complete skeleton	A Rhomaleosaurid	Rhomaleosaurus cramptoni holotype cast
	R. zetlandicus	Loftus (also Lofthouse) Alum Mine	Alum Shale Member	YORYM G503, a partial skeleton[10]
	R. cramptoni	Alum quarry, Kettleness		NMING F8785, a partial skeleton
Plagiophthalmosuchus	P. gracilirostris	Whitby			Teleosaurid
Temnodontosaurus[11]	Temodontosaurus sp.	Oakham		Full skeleton	Ichthyosaur
?Theropoda	Indeterminate			Femur, currently lost[12]
Tetanurae	Indeterminate			Incomplete anterior dorsal vertebra[13]	Originally referred to Streptospondylus cuvieri.

Insects

Insect compression fossils are known from nodules found on Alderton Hill near Alderton and Dumbleton in Gloucestershire, including Alderton Hill Quarry and other nearby localities.^[14]

See also

• List of fossiliferous stratigraphic units in England
• Toarcian turnover
• Toarcian formations