| Kimmeridge Clay | |
|---|---|
| Stratigraphic range: | |
|   Grey cliffs of Upper Kimmeridge Clay above the beach at Egmont Bight   | |
| Type | Geological formation | 
| Unit of | Ancholme Group (onshore), Humber Group (offshore) | 
| Sub-units | Birch Sandstone Member Burns Sandstone Member Claymore Sandstone Member Dirk Sandstone Member Magnus Sandstone Member Ptarmigan Sandstone Member Ribble Sandstone Member  | 
| Underlies | Portland Sand Formation, Speeton Clay Formation, Spilsby Sandstone | 
| Overlies | Ampthill Clay, Corallian Group | 
| Lithology | |
| Primary | Mudstone | 
| Other | Siltstone, Sandstone, Conglomerate | 
| Location | |
| Region |  England (surface) North Sea (subsurface)  | 
| Country | United Kingdom | 
| Type section | |
| Named for | Kimmeridge Bay | 
| Location | Type section - North Sea well 47/15- 1 at 885-919 m depth  Type area - coastal outcrops from Black Head, Weymouth to Chapman's Pool  | 
The Kimmeridge Clay is a sedimentary deposit of fossiliferous marine clay which is of Late Jurassic to lowermost Cretaceous age and occurs in southern and eastern England and in the North Sea. [1] This rock formation is the major source rock for North Sea oil. The fossil fauna of the Kimmeridge Clay includes turtles, crocodiles, sauropods, plesiosaurs, pliosaurs and ichthyosaurs, as well as a number of invertebrate species.
|   | This section needs expansion. You can help by adding to it.  (May 2016)  | 
Kimmeridge Clay is named after the village of Kimmeridge on the Dorset coast of England, where it is well exposed and forms part of the Jurassic Coast World Heritage Site. [2] Onshore, it is of Late Jurassic (Kimmeridgian) age and outcrops across England, in a band stretching from Dorset in the south-west, north-east to North Yorkshire. Offshore, it extends into the Lower Cretaceous (Berriasian Stage) and it is found throughout the Southern, Central and Northern North Sea. [1]
The foundations of the Humber Bridge on the southern (Barton) side of the bridge are on Kimmeridge Clay beneath superficial deposits, under the Humber estuary. [3]
Kimmeridge Clay is of great economic importance, [2] being the major source rock for oil fields in the North Sea hydrocarbon province. [4] It has distinctive physical properties and log responses. [5]
Color key
  | Notes Uncertain or tentative taxa are in small text;  | 
Fauna uncovered from the Kimmeridge Clay include: [6]
| Ray-finned fishes of the Kimmeridge clay Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images | 
T. kimmeridgensis [9]  | Isle of Purbeck, Dorset  | Most common Kimmeridge clay fish, known from several complete specimens  | Housed at the Etches Collection, discovered by Steve Etches. Most prominently distinguished from other species of the Genus by the irregular size of its dentary teeth.  | |||
Indeterminate  | Dorset  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Dorset  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Dorset  | One specimen, a fin  | Housed at the Etches Collection, discovered by Steve Etches  | |||
Indeterminate  | Dorset  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Dorset  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Dorset  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Dorset  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
H.tenuirostris  | Dorset  | Rare  | Housed at the Etches Collection, discovered by Steve Etches  | |||
Indeterminate  | Dorset  | Rare  | Housed at the Etches Collection, discovered by Steve Etches  | |||
Indeterminate  | Dorset  | Rare, one complete specimen  | Housed at the Etches Collection, discovered by Steve Etches  | |||
Indeterminate  | Dorset  | Fairly common, multiple near complete specimens.  | Housed at the Etches Collection, discovered by Steve Etches  | |||
| Lobe-finned fishes of the Kimmeridge clay Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images | 
Indeterminate  | Dorset  | One specimen, cranial material  | Coelacanth. Housed at the Etches Collection, discovered by Steve Etches. More than 2 metres long  | |||
| Cartilaginous fishes of the Kimmeridge clay Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images | 
Indeterminate  | Dorset  | Known from many dorsal spines  | Housed at the Etches Collection, discovered by Steve Etches  | |||
Indeterminate  | Known from many dorsal spines  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Known from many dorsal spines, perhaps a complete head  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | One specimen  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
Indeterminate  | Known from a complete specimen, and other isolated remains  | Housed at the Etches Collection, discovered by Steve Etches  | ||||
K. etchesi  | Encombe (holotype) and Rope Lake Head (paratype)  | Known from two partial skeletons  | An asterodermid ray; housed at the Etches Collection, discovered by Steve Etches  | |||
| Durnonovariaodus [11] | D. maiseyi | Pectinatites pectinatus ammonite zone | One partial skeleton | A hybodontid | ||
| Turtles of the Kimmeridge clay Formation | ||||||
|---|---|---|---|---|---|---|
| Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images | 
| Craspedochelys | C. passmorei | Swindon | "NHMUK R5871 (holotype), subcomplete shell with associated postcranial remains, including parts of the girdles, the left humerus, and partial cervical vertebrae" [12] | Thalassochelydian sea turtle | ||
| Achelonia | A. formosa | Ely, Cambridgeshire | "CAMSM J29898 to CAMSM J29955 (holotype), a partial, disarticulated skeleton" [12] | Thalassochelydian sea turtle, formerly considered the distinct species "Enaliochelyschelonia" [13] | ||
| Pelobatochelys | P. blakii | Weymouth | Carapace fragments | Thalassochelydian sea turtle | ||
| Plesiochelys [14] | P. etalloni | "basicranium with partial otic chambers and fragment of the right maxilla" | Thalassochelydian sea turtle | |||
| Thalassemys | T. bruntrutana, T. hugii | Isle of Purbeck (bruntrutana), Abingdon, Oxfordshire (hugii) | "A partial carapace and associated limb and girdle elements (NHMUK R8699)" (Purbeck) "A large shell (OUMNH J.66966)" (Oxfordshire) [14] | Thalassochelydian sea turtle | ||
| Tropidemys [14] | P. langii | Weymouth | "NHMUK OR44178b, an isolated neural; NHMUK OR45920, right costals 1–3; NHMUK OR45921, a left first costal; NHMUK R2733, a left fourth costal" | Thalassochelydian sea turtle | ||
| Genus | Species | Location | Member | Abundance | Notes | Images | 
|---|---|---|---|---|---|---|
B. megarhinus  | A pelagic teleosaurid. [15]  | |||||
C. gracilis  | ||||||
D. maximus  | A geosaurine metriorhynchid  | |||||
M. brevirostris  | A metriorhynchine metriorhynchid  | |||||
P. manseli  | A geosaurine metriorhynchid  | |||||
T. carpenteri [16]  | A geosaurine metriorhynchid  | |||||
T. coryphaeus [18]  | A geosaurine metriorhynchid  | |||||
Indeterminate ankylosaur osteoderms have been found in Wiltshire, England. [19] Indeterminate stegosaurid remains have been found in Dorset and Wiltshire, England. [6]
| Genus | Species | Location | Member | Abundance | Notes | Images | 
|---|---|---|---|---|---|---|
C. prestwichii [6]  | 
  | "Fragmentary skull and skeleton." [20]  | Iguanodontian | |||
D. armatus [6]  | vertebrae, a massive right femur (thigh bone), ribs and a near complete pelvis. | Stegosaur. Wiltshire remains include specimens previously referred to Omosaurus armatus and O. hastiger. [6]  | ||||
Indeterminate [6]  | 
  | Kimmeridge clay remains considered to represent a possible close relative of Bugenasaura [21] are now regarded as the remains of an indeterminate euornithopod. [6] (The specimen may have had its locality and horizon mislabelled.)  | ||||
O.armatus [6]  | 
  | Reclassified as Dacentrurus armatus because the generic name Omosaurus was preoccupied. [6] | ||||
O. hastiger [6]  | 
  | |||||
Indeterminate ornithomimmid remains have been found in Dorset, England. [6] An undescribed theropod genus was found in Dorset. [6]
| Genus | Species | Location | Stratigraphic position | Material | Notes | Images | 
|---|---|---|---|---|---|---|
B. suffosus [6]  | 
  | "[Seven] dorsal and sacral centra." [22]  | Considered a nomen dubium. | |||
C. humerocristatus [6]  | 
  | Now Duriatitan . [23]  | ||||
Indeterminate [6]  | 
  | Remains previously referred to an indeterminate species of Cetiosaurus are now regarded as indeterminate sauropod material. [6]  | ||||
D. humerocristatus  | 
  | |||||
G. megalonyx [6]  | 
  | Remains previously referred to Gigantosaurus megalonyx are now regarded as indeterminate sauropod material. [6]  | ||||
" Ischyrosaurus " [6]  | 
  | "Humerus." [25]  | Remains previously referred to Ischyrosaurus manseli are now regarded as indeterminate sauropod material. [6]  | |||
J. langhami  | 
  | Partial skeleton  | A primitive tyrannosaur  | |||
| Torvosaurus [28] | Indeterminate | 
  | Tibia (OUMNH J.29886) and maxilla fragment, collected separately | A megalosaurid | ||
Indeterminate  | A tooth from Foxhangers, Wiltshire (NHMUK 46388), phalanges from an unspecified locality in Wiltshire (DZSWS 3009), and a proximal caudal vertebra from Shotover, Oxfordshire (OUMNH J.47134). [28] | Remains previously referred to Megalosaurus are now regarded as indeterminate theropod material. [6]  | ||||
Indeterminate [6]  | Remains previously attributed to one or more indeterminate species of Ornithopsis (incl. O. leedsii) are now regarded as possible indeterminate sauropod material. [6]  | |||||
| Genus | Species | Location | Material | Notes | Images | 
|---|---|---|---|---|---|
| Cuspicephalus | C. scarfi [29] | Dorset | Partial Skull | Missing Crest, lower jaw and dentition | |
| Germanodactylus | indeterminate [30] | Charnel, Dorset | May be a non-pterodactyloid monofenestratan instead [29] | ||
| Rhamphorhynchus | R. etchesi [31] | Encombe, Dorset [31] | |||
| Ctenochasmatoidea | indeterminate [32] | Abingdon, Oxfordshire | Left first wing finger phalanx | 
| Genus | Species | Location | Member | Abundance | Notes | Images | 
|---|---|---|---|---|---|---|
B. swindoniensis  | Plesiosaur of unknown affinities  | |||||
C. megadeirus  | ||||||
C. trochantericus  | Nomen dubium  | |||||
K. langhami  | A cryptoclidid  | |||||
"P." manseli  | Distinct from Colymbosaurus. [33]  | |||||
P. brachydeirus  | ||||||
P. brachyspondylus [34]  | Nomen dubium  | |||||
P. carpenteri  | A thalassophonean pliosaurid  | |||||
P. kevani  | A thalassophonean pliosaurid  | |||||
P. portentificus [36]  | A nomen dubium  | |||||
P. ?rossicus  | A thalassophonean pliosaurid; taxonomic identification of specimens tentative [34]  | |||||
P. westburyensis  | A thalassophonean pliosaurid  | |||||
P. sp. 1  | Partial skeleton, CAMSM J.35991  | A thalassophonean pliosaurid; previously assigned to the nomen dubiumP. brachyspondylus [34] [35]  | ||||
P. sp. 2  | Mandible, NHMUK PV OR 39362  | A thalassophonean pliosaurid; previously assigned to the nomen dubiumP. macromerus [34] [35]  | ||||
Indeterminate  | ||||||
| Genus | Species | Location | Stratigraphic Position | Abundance | Notes | Images | 
|---|---|---|---|---|---|---|
B.extremus  | Dorset  | |||||
G.mordax  | Dorset  | |||||
Indeterminate  | Dorset  | Giant, near complete specimen. Proposed to have been 6 metres long when complete. Housed at the Etches Collection in Dorset.  | ||||
M.trigonus  | Dorset  | Nomen dubium - classified by a single vertebra  | ||||
N.enthekiodon  | Dorset  | |||||
T. etchesi  | Dorset  | The Pectinatites pectinatus ammonite zone  | ||||
Indeterminate  | Dorset  | |||||
 The invertebrate fauna of the Kimmeridge Clay includes: [37] [38]