Inferior Oolite

Inferior Oolite Group
Stratigraphic range: Aalenian–Bathonian PreꞒ Ꞓ O S D C P T J K Pg N (Middle Jurassic)
Inferior Oolite at Leckhampton Hill, Gloucestershire.
Type	Group
Sub-units	East Midlands Lincolnshire limestone Grantham Formation Northampton Sand Formation Cotswolds Salperton Limestone Aston Limestone Birdlip Limestone Dorset -Lower, Upper Inferior Oolite Formations
Underlies	Great Oolite Group
Overlies	Lias Group
Thickness	0 - 120 m
Lithology
Primary	limestones
Other	sandstone, mudstone
Location
Country	England

The Inferior Oolite is a sequence of Jurassic age sedimentary rocks in Europe. It was deposited during the Middle Jurassic.^[1] The Inferior Oolite Group as more recently defined is a Jurassic lithostratigraphic group (a sequence of rock strata) in southern and eastern England . It has been variously known in the past as the Under Oolite (or Oolyte), the Inferior Oolite, the Inferior Oolite Series and the Redbourne Group.^[2]

The rocks are exposed from Dorset and Somerset eastwards and northwards through the English Midlands to Yorkshire.^[3] It is present at depth in the Wessex-Weald Basin, where it reaches its greatest thickness of 120 m.

The group consists of up to 120 m thickness of oolitic limestones and subordinate sandstones and mudstones laid down during the Jurassic Period. In the East Midlands it consists of (in descending order i.e. oldest last) the Lincolnshire Limestone, Grantham and Northampton Sand formations whereas in the Cotswold Hills it consists of the Salperton Limestone, Aston Limestone and Birdlip Limestone formations.^[4][5] The limestones are rich in organic material. The ammonite Parkinsonia parkinsoni, an index fossil for the Bathonian,^[6] is native to the Inferior Oolite of Burton Bradstock.^{[citation needed]}

Within Dorset, the Oolite is not subdivided into separately named formations, but is simply considered the Inferior Oolite Formation, sometimes subdivided into the Lower and Upper Inferior Oolite Formations. Within the vicinity of Yeovil it is divided into members which are in ascending order the Corton Denham Member, which predominantly consists of blue siltstone is about 2.5 m thick with the transitional top consisting of green Marl, the Oborne Ironshot Member, the term "ironshot" refers to ferruginised Oolite.^[7] The upper portion of which contains intensely bioturbated limestone. Moving Into the Upper Inferior Oolite the Sherborne Limestone Member, which consists of exposed yellow brown fresh grey bioclastic limestone, while the overlying Combe Limestone Member, consists of rubbly limestone and marl, a full stratigraphy of the locality is given below

Ornithopod tracks geographically located in North Yorkshire, England.^[1] Ornithopod and theropod tracks present in North Yorkshire, England.^[9] A supposed dermal spine long thought to be from a stegosaur is actually a caudal vertebra referable to Archosauria indet.^[10]

Dinosaurs of the Inferior Oolite
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Cetiosaurus	C. epioolithicus	North Yorkshire, England.[9]
	Indeterminate	Wiltshire, England.[11]
Duriavenator	D. hesperis	Dorset, England.[12]		"Skull elements."[13]
Magnosaurus[12]	M. nethercombensis[12]	Dorset, England.[12]		"Dentaries, vertebrae, pubis, femora, [and] tibiae."[13]
Megalosaurus[1]	M. hesperis[1]	Dorset, England.[12]		"Skull elements."[13]	Moved to the new genus Duriavenator in 2008.
	Indeterminate	Northamptonshire, England.[14] Somerset, England.[15]			Indeterminate Megalosaurid material.
Thyreophora	Indeterminate[10]	Dorset, England.[1]

• List of dinosaur-bearing rock formations

• M. J. Benton and P. S. Spencer. 1995. Fossil Reptiles of Great Britain. Chapman & Hall, London 1-386
• J. B. Delair. 1973. The dinosaurs of Wiltshire. The Wiltshire Archaeological and Natural History Magazine 68:1-7
• Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. 861 pp. ISBN 0-520-24209-2.