Lulworth Formation

The Lulworth Formation is a geologic formation in England. It dates from the late Tithonian to the mid Berriasian. It is a subunit of the Purbeck Group.[1] In Dorset, it consists of three members, which are in ascending order, the Mupe Member, the Ridgway Member, and the Warbarrow Tout Member. The Mupe Member is typically 11 to 16 m thick and largely consists of marls and micrites with interbeds of calcareous mudstone.[2] The Ridgeway Member is about 3 to 7 m thick and consists of in its western portion carbonaceous muds, marls and micrites, in the east the muds are replaced by micritic limestone.[3] The Warbarrow Tout Member is 17 to 39 m thick and consists of limestone at the base and micrite and mudstone for the rest of the sequence,[4] this member is the primary source of the vertebrate fossils within the formation.[5][6] Elsewhere the unit is undifferentiated.

Lulworth Formation Stratigraphic range: Tithonian - Berriasian 152–139 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Lulworth Cove, an area where the Lulworth Formation is exposed
Type	Formation
Unit of	Purbeck Group
Sub-units	Worbarrow Tout Member Ridgway Member Mupe Member
Underlies	Durlston Formation
Overlies	Portland Stone Formation
Thickness	In Dorset 27-63 metres, In Weald 86 m Vale of Wardour up to 15m
Lithology
Primary	Calcarenite, Micrite, Mudstone, Marl
Other	Gypsum
Location
Region	England
Country	United Kingdom
Type section
Named for	Lulworth
Location	West side of Worbarrow Tout

Vertebrate paleobiota

Amphibians

Amphibians reported from the Lulworth Formation[7]
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Apricosiren	A. ensomi		Worbarrow Tout Member		Salamander
Celtedens	C. megacephalus		Worbarrow Tout Member		Albanerpetonid
Sunnybatrachus	S. purbeckensis		Worbarrow Tout Member		Frog, affinites to Discoglossidae
?Batrachosauroididae	Indeterminate		Worbarrow Tout Member		Salamander

Turtles

Turtles reported from the Lulworth Formation[8]
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Dorsetochelys	D. typocardium, D. delairi				Both species probably represent the same taxon[9]
Helochelydra	H. anglica
Hylaeochelys	H. latiscutata
Pleurosternon	P. bullocki

Lepidosaurs

Lepidosaurs reported from the Lulworth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Becklesius	Indeterminate
Dorsetisaurus	D. hebetidens, D. purbeckensis
Durotrigia	D. triconidens
Homoeosaurus	Indeterminate				Rhynchocephalian
Opisthias	Indeterminate				Rhynchocephalian
Paramacellodus	P. oweni
Parasaurillus	P. pseudobtusus
Parviraptor	P. estesi				Stem-snake
Pseudosaurillus	P. becklesi
Purbicella	P. ragei
Saurillus	S. robustidens

Crocodyliformes

Crocodyliformes reported from the Lulworth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
cf. Bernissartia	Indeterminate			Teeth
Goniopholis	Indeterminate
Nannosuchus	N. gracilidens
Theriosuchus	T. pusillus

Dinosaurs

Dinosaurs reported from the Lulworth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Echinodon	E. becklesii[10]	Durlston Bay, Swanage[10]		Teeth and dentary	A small heterodontosaurid
Owenodon	O. hoggii[11]	Durlston Bay, Swanage		Partial dentary	An iguanodontoid
Nuthetes	N. destructor[12]	Feather Quarry, Durlston Bay, Swanage		Teeth, dentary fragment	Small dromaeosaur

Mammals

Mammals reported from the Lulworth Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Albionbaatar	A. denisae	Sunnydown Farm Quarry			Albionbaataridae
Amblotherium	A. pusillum, A. soricinum, A. nanum	Mammal Bed
Bolodon	B. minor, B. crassidens, B. osborni, B. elongatus, B. falconeri	Mammal Bed			Plagiaulacidae
Chunnelodon	C. alopekodes	Sunnydown Farm Quarry
Ctenacodon	C. minor	Mammal Bed			Allodontidae
Dorsetodon	D. haysomi	Sunnydown Farm Quarry			Paurodontidae
Durlstotherium	D. newmani	Mammal Bed
Durlstodon	D. ensomi	Mammal Bed
Gerhardodon	G. purbeckensis	Sunnydown Farm Quarry			Pinheirodontidae
Kouriogenys	K. minor	Mammal Bed			Peramuridae
Magnimus	M. ensomi	Sunnydown Farm Quarry
Peraiocynodon	P. inexpectatus	Mammal Bed			Docodontidae
Peramuroides	P. tenuiscus	Mammal Bed			Peramuridae
Peramus	P. tenuirostris, P. dubius, P. minor	Mammal Bed			Peramuridae
Peraspalax	P. talpoides	Mammal Bed, Sunnydown Farm Quarry			Dryolestidae
Phascolestes	P. mustelula	Mammal Bed, Sunnydown Farm Quarry			Dryolestidae
Plagiaulax	P. becklesii	Mammal Bed			Plagiaulacidae
Purbeckodon	P. batei	Sunnydown Farm Quarry			Morganucodonta
Spalacotherium	S. tricuspidens, S. evansae, S. hookeri	Mammal Bed, Sunnydown Farm Quarry			Spalacotheriidae
Sunnyodon	S. notleyi	Sunnydown Farm Quarry			Paulchoffatiidae
Thereuodon	T. taraktes	Sunnydown Farm Quarry
Tinodon	T. micron	Sunnydown Farm Quarry			Tinodontidae
Triconodon	T. mordax	Mammal Bed, Sunnydown Farm Quarry
Trioracodon	T. bisulcus, T. major, T. oweni	Mammal Bed, Feather Quarry

See also

• List of fossiliferous stratigraphic units in England
• List of dinosaur bearing rock formations

References

1. "Lulworth Formation". BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 28 August 2018.
2. "Mupe Member". BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 28 August 2018.
3. "Ridgeway Member". BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 28 August 2018.
4. "Warbarrow Tout Member". BGS Lexicon of Named Rock Units. British Geological Survey. Retrieved 28 August 2018.
5. "Sunnydown Farm Quarry (clay: upper horizon; equivalent to DB 102/103 )". Paleobiology Database. Retrieved 28 August 2018.
6. "Mammal Bed, Durlston Bay (DB83)". Paleobiology Database. Retrieved 28 August 2018.
7. Evans, Susan E.; McGowan, Gerard J. (2002). "Lissamphibian remains from the Purbeck Limestone Group, southern England". Special Papers in Palaeontology: 104–119.
8. Milner, Andrew R. (November 2004). "The turtles of the Purbeck Limestone Group of Dorset, southern England" (PDF). Palaeontology. 47 (6): 1441–1467. doi:10.1111/j.0031-0239.2004.00418.x. ISSN 0031-0239.
9. Pérez-García, A. (May 2014). "Revision of the poorly known Dorsetochelys typocardium, a relatively abundant pleurosternid turtle (Paracryptodira) in the Early Cretaceous of Europe". Cretaceous Research. 49: 152–162. doi:10.1016/j.cretres.2014.02.015. ISSN 0195-6671.
10. "Type specimen: BMNH 48209, 48210, a mandible. Its type locality is cliff face, Durlston Bay, which is in a Berriasian fluvial-lacustrine limestone in the Lulworth Formation of the United Kingdom". fossilworks.org.
11. "Type specimen: BMNH R2998. Its type locality is Durlston Bay, Swanage (DB105-107), which is in a Berriasian marine limestone in the Lulworth Formation of the United Kingdom".
12. "Type specimen: DORCM G913, a mandible. Its type locality is Feather Quarry, Durlston Bay (DB102), which is in a Berriasian marine shale in the Lulworth Formation of the United Kingdom".