Lulworth Formation

Lulworth Formation
Stratigraphic range: Tithonian - Berriasian
Lulworth Cove, an area where the Lulworth Formation is exposed
TypeFormation
Unit ofPurbeck Group
Sub-units
  • Worbarrow Tout Member
  • Ridgway Member
  • Mupe Member
UnderliesDurlston Formation
OverliesPortland Stone Formation
ThicknessIn Dorset 27-63 metres, In Weald 86 m Vale of Wardour up to 15m
Lithology
PrimaryCalcarenite, Micrite, Mudstone, Marl
OtherGypsum
Location
RegionEngland
CountryUnited Kingdom
Type section
Named forLulworth
LocationWest side of Worbarrow Tout

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.

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 Albanerpetontid
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

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. Bibcode:2004Palgy..47.1441M. 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. Bibcode:2014CrRes..49..152P. doi:10.1016/j.cretres.2014.02.015. ISSN 0195-6671.
  10. 1 2 "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".


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