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

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

in age. It lies above the erosive contact between the Gault Formation 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 ac ...

in the vicinity of

Cambridgeshire Cambridgeshire (abbreviated Cambs.) is a Ceremonial counties of England, ceremonial county in the East of England and East Anglia. It is bordered by Lincolnshire to the north, Norfolk to the north-east, Suffolk to the east, Essex and Hertfor ...

, 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 (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

age, including those of dinosaurs and pterosaurs.

Description

The lithology is made out of glauconitic

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

, described as a "chalk mud", containing abundant

ostracod Ostracods, or ostracodes, are a Class (biology), class of the crustacean, Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 33,000 species (only 13,000 of which are extant taxon, extant) have been identified,Brandão, S.N.; Antoni ...

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

Vertebrate paleofauna

Birds

Dinosaurs

Ornithischians

Saurischians

Pterosaurs

Ichthyosaurs

Lepidosauria

Invertebrates

Ammonites

* '' 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