The Cambridge Greensand is a geological unit in England whose strata are earliest

Cenomanian The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...

in age. It lies above the erosive contact between the

Gault Formation The Gault Formation is a geological formation of stiff blue clay deposited in a calm, fairly deep-water marine environment during the Lower Cretaceous Period (Upper and Middle Albian). It is well exposed in the coastal cliffs at Copt Point in Fol ...

and the

Chalk Group The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur acr ...

in the vicinity of

Cambridgeshire Cambridgeshire (abbreviated Cambs.) is a Counties of England, county in the East of England, bordering Lincolnshire to the north, Norfolk to the north-east, Suffolk to the east, Essex and Hertfordshire to the south, and Bedfordshire and North ...

, and technically forms the lowest member bed of the West Melbury Marly Chalk Formation.Cambridge Greensand
at BGS It is a remanié deposit, containing reworked fossils of late

Albian The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous Epoch/Series. Its approximate time range is 113.0 ± 1.0 Ma to 100.5 ± 0.9 M ...

age, including those of dinosaurs and pterosaurs.

Description

The lithology is made out of

glauconitic Glauconite is an iron potassium phyllosilicate (mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek () me ...

marl Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. Marl makes up the lower part o ...

, described as a "chalk mud", containing abundant

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

coccolith Coccoliths are individual plates or scales of calcium carbonate formed by coccolithophores (single-celled phytoplankton such as ''Emiliania huxleyi'') and cover the cell surface arranged in the form of a spherical shell, called a ''coccosphere''. ...

and

foram Foraminifera (; Latin for "hole bearers"; informally called "forams") are single-celled organisms, members of a phylum or class of amoeboid protists characterized by streaming granular ectoplasm for catching food and other uses; and commonly a ...

remains, with a concentration of phosphatic nodules and bones at the base.

Vertebrate paleofauna

Birds

* '' Enaliornis barrette'' - "Braincases, vertebrae, pelvis ndlimb elements..""Table 11.1," in Weishampel, et al. (2004). Page 215. * '' E sedgwicki'' - "Hindlimb elements." * '' E. seeleyi'' - "Assorted cranial and postcranial elements"

Dinosaurs

Ornithischians

* '' Anoplosaurus curtonotus'' - "Partial postcranium.""Table 17.1," in Weishampel, et al. (2004). Page 367. * '' A. major'' - "Cervical vertebrae." "Vertebrae.""Table 19.1," in Weishampel, et al. (2004). Page 417. * ''

Acanthopholis eucercus ''Acanthopholis'' (; meaning "spiny scales") is a genus of ankylosaurian dinosaur in the family Nodosauridae that lived during the Late Cretaceous Period of England. A single species, ''A. horrida'', exists. History Around 1865 commercial foss ...

'' - " wocaudal centra." * '' Acanthopholis platypus'' (in part) - "Phalanx, caudal centra." * '' Acanthopholis macrocercus'' (aka ''Syngonosaurus)'' - "Osteoderms." "Vertebrae, fragmentary skeleton elements." * '' Acanthopholis stereocercus'' - "Osteoderms." "Vertebrae." * '' Eucercosaurus tanyspondylus'' - "Vertebrae." * '' Trachodon cantabrigiensis'' - "Dentary tooth.""Table 20.1," in Weishampel, et al. (2004). Page 443.

Saurischians

* '' Macrurosaurus semnus'' - "Caudal vertebrae""Table 13.1," in Weishampel, et al. (2004). Page 270.

Pterosaurs

* '' Amblydectes crassidens'' * '' A. eurygnathus'' * '' Camposipterus colorhinus'' * '' C. nasutus'' * '' Camposipterus sedgwickii'' * '' Draigwenia platystomus'' * '' Lonchodraco machaerorhynchus'' * '' Lonchodraco microdon'' * ''

Ornithocheirus simus ''Ornithocheirus'' (from Ancient Greek "ὄρνις", meaning ''bird'', and "χεῖρ", meaning ''hand'') is a pterosaur genus known from fragmentary fossil remains uncovered from sediments in the UK and possibly Morocco. Several species have ...

'' * '' Nicorhynchus capito'' * "Ornithocheirus" denticulatus * "Ornithocheirus" polyodon * '' Ornithostoma sedgwicki''

Ichthyosaurs

* '' Cetarthrosaurus walkeri'' * '' Maiaspondylus cantabrigiensis'' (originally ''

Ophthalmosaurus ''Ophthalmosaurus'' (meaning "eye lizard" in Greek) is an ichthyosaur of the Jurassic period (165–150 million years ago). Possible remains from the Cretaceous, around 145 million years ago, are also known. It was a relatively medium-sized ich ...

'') * '' Pervushovisaurus campylodon'' * '' Sisteronia seeleyi''

Lepidosauria

* '' Patricosaurus merocratus''

Invertebrates

Ammonites

* '' Salaziceras (Salaziceras) salazacense''C. W. Wright and W. J. Kennedy. 1979. Origin and evolution of the Cretaceous micromorph ammonite family Flickiidae. Palaeontology 22:685-704

References

{{Reflist Geologic formations of England Upper Cretaceous Series of Europe Cenomanian Stage Cretaceous England Marl formations Paleontology in England