Oxford Clay

The Oxford Clay is a special kind of rock formed from ancient sea mud. It lies under much of southeast England, stretching from Dorset in the west to Yorkshire in the north. This rock formed during the time of the dinosaurs, in what scientists call the Jurassic period, especially during the Callovian and Oxfordian ages.

Oxford Clay is made up of two main parts. The lower part, called the Peterborough Member, is rich in fossils and organic material, and is often called lower Oxford Clay. The upper part includes the Stewartby Member and the Weymouth Member, and it contains fewer fossils and more limestone.

You can see Oxford Clay near cities like Oxford, Peterborough, and Weymouth, and it is often found in quarries in these areas. The rock changes from shale to mudstone near the top of the lower layer, and the middle and upper layers are separated by a special kind of limestone in some places.

Palaeontology

The Oxford Clay is famous for its many fossils of fish and invertebrates. These fossils are often very well preserved, and some are found in amazing condition. Animals that lived in the ancient Oxford Clay Sea include plesiosaurs, marine crocodiles, ichthyosaurs, cephalopods like belemnites, bivalves such as Gryphaea, and many gastropods. Dinosaur eggs have also been found in the lower part of the Oxford Clay in Cambridgeshire, England.

Fossil Content

The Oxford Clay contains many fossils from ancient animals that lived in the sea long ago. Some parts of this rock have pieces of dinosaurs called euronithopods found in a place called Cambridgeshire in England.

There are also fossils of flying reptiles called pterosaurs, as well as other sea creatures like ichthyosaurs, plesiosaurs, fish called pachycormiformes, and thalattosuchians.

Ornithischians of the Oxford Clay
Genus	Species	Location	Stratigraphic position	Material	Images
Callovosaurus	C. leedsi	Cambridgeshire	Lower	"Femur."
Lexovisaurus	L. durobivensis	Cambridgeshire Dorset	Lower	A holotype pelvis.
	Indeterminate	Bedfordshire
Loricatosaurus	L. priscus	Cambridgeshire	Lower
Sarcolestes	S. leedsi	Cambridgeshire	Lower	"Partial mandible."

Saurischians of the Oxford Clay
Genus	Species	Location	Stratigraphic position	Material	Images
Cetiosauriscus	C. stewarti	Cambridgeshire	Lower	"Rear half of a skeleton."
Eustreptospondylus	E. oxoniensis	Oxfordshire	Upper	Disarticulated skull and skeleton, with some referred limb elements.
Sauropoda	Indeterminate	Wiltshire Cambridgeshire
Theropoda	Indeterminate	Oxfordshire	Middle
Metriacanthosaurus	M. parkeri	Weymouth	Upper

Genus	Species	Images
Cryptoclidus	C. eurymerus
	C. richardsoni
Eardasaurus	E. powelli
Liopleurodon	L. ferox
	L. pachydeirus
Marmornectes	M. candrewi
Muraenosaurus	M. leedsi
Pachycostasaurus	P. dawnii
Peloneustes	P. philarchus
Picrocleidus	P. beloclis
Pliosaurus	P. andrewsi
Simolestes	S. vorax
Tricleidus	T. seeleyi

Genus	Species	Images
Lemmysuchus	L. obtusidens
Charitomenosuchus	C. leedsi
Steneosaurus	S. edwardsi
	S. durobrivensis
Neosteneosaurus	N. edwardsi
Mycterosuchus	M. leedsi
Metriorhynchus	M. superciliosus
Thalattosuchus	T. superciliosus
Gracilineustes	G. leedsi
Suchodus	S. brachyrhynchus
	S. durobrivensis
Tyrannoneustes	T. lythrodectikos

Economic use

Oxford Clay is soft and porous, making it useful for building roads. It is also used to make the Fletton stock brick, which helped build much of London. One advantage of using Oxford Clay for bricks is that it contains carbon, which helps provide fuel when the bricks are fired, meaning less outside fuel is needed.